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Just for the heck of it while mowing this morning I checked temps of engine and drives with infrared gun.
Here in central Oklahoma it getting hot, when I started it was 82 and 85 when I finished.

I have a Husqvarna 4623 zero turn, it has dreaded kohler courage and hydro gear EZT drives.
At 20 min. Oil filter was at 180* and block was 142*, drives were at 126*
At 40 min oil was 200* block was 155*, drives were 135*
At one hr oil was 212* block 168*, drives were 140* this was after mowing my thickest pat of lawn.
At 1 hr and 20 min when I finished oil was 200*,block 150* and drives were 148*

As of today mower has 87.8 hrs.
I bought mower at Husqvarna dealer 4/26/13, I wasn't sure that we needed a zero turn so I went low end on first one just to see (will never go back to lawn tractor)
Plan to run this as long as it will go just to see how long EZT drives will last, so far no problem with engine or drives.
I'll revive this thread if problems show up.
Mike.

Since 2011 when I first joined you are the only one I have seen to ever publish heat figures and that is great! But tell how you measured oil temp with a gun? No one here has ever said anything about expected surface temps. My Intek runs oil between 240F and 300F measured on an oil temp gauge reading a probe sticking through the drain plug into the sump. Anything above 280F bothers me and I stop and cool down at 300F. This is also mowing at about 85F with 3 full baskets.

Thanks motoman, I don't know how close it is but I was shooting infrared gun at oil filter, I have an extra plug on oil filter housing and have thought of putting temp or pressure gage on it.
The highest temp in 1hr 20 min was 217* on filter, on block I was shooting middle of engine, on drives it was middle of front,
Engine was at full throttle.

"IF" these AC engines run about the same then in normal temp range the filter housing and filter are pulling ? 240F(mine)-215F(yours)=35F off the oil? I know this is a long reach. There are several good gauge kits available on line. And I also have the Lowes pn for the Briggs (Intek) pipe-threaded OD, temp sender OD plug, in brass (one piece adapter). That is for those who do not want to drill and tap their sump plug. My gauge has been on about 3 years without a problem (vibrations , etc). There used to be some finned aluminum sleeves that fit oil filters. Have not pursued them. If available they might pull off another 10-15F? Poor man's oil cooler :laughing:

Another ref point for you . Several summers ago I set up a temp probe on the head. It was the classic VW-type spark plug sender. Results @ 85F ambient: 305F.

Edit 2: Re finned filter sleeves. Scrap the idea. Chatter on several Harley blogs says a waste and no detectable drop in temp with the finned sleeves, even with motorcycle air blast.

I've been running Rotella t15w40 for about 20 years in all my small engines, I don't know if that would keep it any cooler or not, what do you use ?

OIL is like an emotional magnet here...I do not believe synthetic oil runs cooler, but it does work better at low temps . I now run Mobil 1 5W-30 only because it is common to wife's car. It is well established that thinner oil cools better, but (IMO) AC engines and hi po car engines are built with more piston/bore clearance and so do consume some oil. The Intek does require topping after a couple hours-about 2 oz, partly because I have a little leak on one valve cover, but mostly normal consumption. Consumer reports has just gone anal on the "bad cars" which use some oil-I won't comment, but wonder what real world experience their "engineers" have.

Oh I know about the oil and many many views LOL.
Only reaso I use Rotella 15w40 is I had trucking company and when I sold out we had a 55 gal drum of it left so I use it in my pickup and small engines, I've never had a problem using it in small engine.
Just for a test I might put 10w30 in it next change and see what temps are, I have 2 quarts of casterol gtx.
As a matter of fact I'm courious now and will change just to see on next mow ?

gainestruk said:

Thanks motoman, I don't know how close it is but I was shooting infrared gun at oil filter, I have an extra plug on oil filter housing and have thought of putting temp or pressure gage on it.
The highest temp in 1hr 20 min was 217* on filter, on block I was shooting middle of engine, on drives it was middle of front,
Engine was at full throttle.

Click to expand...

....excellent work, fella, I have always used my hands and count 1, 000 1 1, 000.
Yeah, stooopid :laugh:

Point being I could not tell you a temp range beyond "hot" and " bloody hot"!
Your work has convinced me to go buy a gun. We get 40C plus ambients here
and often from 7AM till 5PM.

Thanks

KK

When cooking bacon you can press your palm onto the skillet edge , but not for long. Think of that as 350F. but seriously...the better DVMs have temp probes. This can end your guesswork. I tried making a probe and using the dipstick tube to get sump temp. You are rewarded with a hot oil spattered face from case pressure, but a better idea of how hot these bad boy AC engnes are. :wink:

Edit, Incidentally, Unless your engine is a lot smoother than mine go to electric sender for oil pressure gauge. I tried and failed at least 4 times to keep the little tube and fittings tight at the filter connection and was rewarded 4 times with separation and an oil splattered driveway. The electrics are more expensive and the "can" sender is kinda big but no problems after 3-4 years.

Ok guy's, here is my 2nd test.
Like I said last post I changed oil and filter with 2 quarts Quaker state 5w30 full synthetic that I had for generator.
(I know I said 10w30 but it turned out to be synthetic 5w30)

Now this gets interesting, the ambenent temp was 80* at start and 83* at finish which was only 2* cooler than last time.
20 min. Oil filter=160*, block=127.5*, drives=100.7*
40 min. =166.6* =136.7* =114.0*
60 min. =174.5* =133.7* =117.6*
80 min. =178.1* =138.0* =128.2*
90 min. =178.0* =155.6* =129.1* (this was at finish after mowing Heaviest part of lawn)

Running at about same conditions including grass thickness I'm running about 50* cooler filter temp and block was about the same.
When checking filter I try to always shoot infra red light at center of filter.

I wasn't expecting to see that much difference between regular 15w40 oil and full synthetic.

Now how about some peer review research, see if anyone else can show same result with regular oil and synthetic.

Mike Gaines

gainestruk said:

Ok guy's, here is my 2nd test.

[Edit data]

Now how about some peer review research, see if anyone else can show same result with regular oil and synthetic.

Mike Gaines

Click to expand...

Excellent work there Mike.
I am up for it, I have some thermistor driven test gear archived....digital outputs.
Two immediate problems I forsee is "dino oil" is very difficult to get, locally.
And it is our winter here, for what that is, and so mows are pretty ordinary, time wise.
Up to an hour is possible, at load.

Stay tuned

KK

Thanks kk, I wouldn't think the outside temp would matter much as long as you check each time you start at the same temp.
I was using HD 15w40 the 1st time, guess I should check 10w30 Dino next, I also got a good price on Rotella t6 5w40 synthetic that I will be running full time after next test on 10w30 Dino.
This is costing a bit of money but I have my interest peeked and really want to check this out.

Mike..

Thanks, If we could get more to contribute we might even find some manufacturers are (apparently) better at fan / shroud, fin cooling , than others. Kaw vs Briggs vs Honda vs Kohler.
Problem is uniformity of procedures and measuring devices.

Ok just went to dollar general and got 2 quarts of Castrol GTX.
I changed oil on Kohler Courage 23hp on my Husqvarna Z Turn I've Been testing all along, it now has Dino 10w30.
I did take new filter off and drained it for several minutes.

For anyone courious I'm recycling all oil I'm using, I take it to Autozone.

Next run will be on 7/16 or 7/17 that will be one week, I'll watch temp close and start at 80* to 82*

Stay tuned :thumbsup:

Mike..

After I changed oil to Dino 10w30 I went and mowed over my septic tank and lateral lines took about 8 min. Air temp. Was around 90* so that's 5* warmer that have been running and checking.
When I finished I shot infra red at filter it was 175.8* and block was 125.8, that's as hot on oil as I got after 90 min.
last time.

Full run and temps this Thursday

Mike, Good work, the temps are really low compared with my (liquid) oil in the Briggs Intek. Interesting ... What gun brand are you using in case any of us try what you did? It is always possible that electric driven sensors (like my Beedee) can vary with (tractor) input voltages, heat and even calibration. I did find that a DVM probe of sump oil was 10 degrees cooler than the Beedee gauge once. This is also analog dial (Beedee) vs digital DVM readouts. Will we find that the Kohler runs cooler??? Even ? assembled in China?? They do make motorcycles and lots of cars.


Edit. Just refreshed that you run a zero turn and I run a big box special. Cynical thought, are riders simply designed to burn up and rebuy...naaw, they wouldn't do that , would they?

The guns name of manufacture is (General) it is a small hand held model # 20140402278
I bought it at Lowes about a year ago.
I've checked it to several known temps and it's right on the money.

As far as what I get take that with a grain of salt as to the accurate temperature just what I'm getting on this unit.
I'm always trying to point gun at same spot to a good average.
Some day I might get a sending unit and try that going straight to the oil.

As far as my mower it is the one of the cheapest zero turn you can get its a RZ4623 made in 2013
I hope we can get some interest and a few others will do what I'm doing.
That way we might see a real difference in oils.

Object moved
Trying a link.
If it works this is what I'm using.
It worked for me, took me to eBay showing the little infra red gun I have.

motoman said:

Mike, Good work, the temps are really low compared with my (liquid) oil in the Briggs Intek. Interesting ... What gun brand are you using in case any of us try what you did? It is always possible that electric driven sensors (like my Beedee) can vary with (tractor) input voltages, heat and even calibration. I did find that a DVM probe of sump oil was 10 degrees cooler than the Beedee gauge once. This is also analog dial (Beedee) vs digital DVM readouts.

Click to expand...

Precisely why we (?) should be posting methods, despite the extra work.
I am going to use both gun and transducer type sensing. When I get me gun, I
am well away (remote) from markets. I will use what I have for now.

Will we find that the Kohler runs cooler??? Even ? assembled in China?? They do make motorcycles and lots of cars.

Click to expand...

Over the India experience the Chinese at least follow some industry standard, albeit
they are known to steal the info at the design phase :}

Edit. Just refreshed that you run a zero turn and I run a big box special. Cynical thought, are riders simply designed to burn up and rebuy...naaw, they wouldn't do that , would they?

Click to expand...

Heh.... I feel a solid class action coming on. Cashed up residents are getting into
tractor and ZTR rides in droves. The units are not priced at gumball (limited chew)
levels, they are a significant investment and sold (promoted) as such. To have a
dealer tell you your machine is "worn out" at four years old and less than 300 hours
of real work - in offering a trade up - is *fskn* insulting.... to your intelligence and the
manufacturing industry per se.
Then again, when I look at just how Kawa put together their rocker cradle I am pushed
to consider your cynicism very seriously as being the actual fact of the matter.

I digress.....

KK

You guys motivated me so I broke out my KE thermometer , mowed, and took some readings. Remember I have a full sized oil cooler on the Intek with electric fan. I usually turn it on at 280F on the Beedee oil temp gauge. Today 82F mowing without bags out the shute on tender green grass. Trying to stay somewhat in the order of Mike's figures...

Engine oil was cooled with fan from indicated 300F liquid oil to 220F

Values : Oil filter (big fram) 110F
Sump case (block) 162F
Sump Plug (sensor 169F
Oil temp gauge 220F (liquid oil)
Oil cooler fitting 118F
Dipstick tube oil 180F *
Rocker cover 140F

*Dipstick tube oil=fished wire probe down into sump, which is a couple inches back of the sump plug.

The oil gauge sensor is like a small pencil and soaks in the oil pool, the KE thermometer pickup is a small 1/2-sized BB on a wire.

Edit. One wonders about the 40F delta between the gauge and the dipstick oil reading...Actually, the KE works like a wall thermostat sender and only the tip should be heated. I heated the length of the wire that was in the dipstick tube. I'll go with the Beedee gauge of 220F

Thanks motoman, Well at least I see with your ke thermometer is getting readings close to what my infra red gun is showing :thumbsup:

After looking at oil cooler and filter surface temps it looks like the cooler really works . But once the oil dumps into the sump it's like a volcano. When I first looked at the temps it was to see how hot the head gets because of a pushed guide. Since the engineers who really know don't respond here we have to make assumptions ourselves. Mine is that the oil cools the engine , but the head is almost entirely on its own (air) with fan and finning. Some cooling must take place as the "cooler" cylinder (s) and block draw off some head heat to be cooled by the oil. Whadda ya ALL think and know??

I have noticed that once hot (300F) the oil will cool down to 250F in about 5 minutes with the fan on at idle. Then it stays below 280F while mowing for about another 5 minutes , but gradually creeps back up. My fan set- up is not optimal.. It will not keep the temp steady down while mowing in summer , typ 85F, but will control excess heat with 5 minute breaks.

It is not a coincidence that analog oil gauges (sweep pointers) are all calibrated up to 300F. My gauge ends at 320F. (shutting up, for now):laughing:

Edit. If heat is drawn down into cylinders it says blown head gaskets are not good. Reduced contact area and heat flow.

Ok test #3
Temperature was 82* at start and 86* at finish.
This time oil is Castrol GTX 10w30 regular Dino.

20 min. Oil filter= 147.9*, engine block= 151.1*, drives= 118.4*
40 min = 172.0*, 146.6*, 123.9*
60 min = 165.3*, 141.1*, 123.4*
80 min = 163.0*, 144.6*, 125.7*
90 min = 176.0*, 170.4*, 125.2*

Will drain this oil to use in my pickup.
Next week when I mow it will be Rotella T6 5W40 full synthetic, I'll be running the T6 from now on.
Stay tuned next mow will be 7/23 or 7/27

Thanks gaines. On another thread there is a "glowing red" exhaust pipe which Il Eng has said he has seen usually in a darkened area. I requested the head temp while pipe is red.
Incidentally, you mentioned upper limit of AC aircraft head of 500F. I ran accross this before and could not reconcile it with the temp of 390F where aluminum begins to soften. Could the aircraft warning limit be for "immediate" action which makes sense with airflow of ?200mph? accross the hot head which would quickly cool it. On the other hand even the best AC small engine flow is much less (I do not know). I do know that before carbon steel changes state to its hardest it must be held for some time at the high temp for the change to occur (and then be quenched). Perhaps the lawn mower engines once at 390F or even a little below cannot recover quickly (cool) and some soften ??? Or maybe the wrong "mix" in a casting makes it more prone to soften? Also anyone please comment on the upward movement of the valve guide when it moves.... How about this: isn't an overheated head immediately shut down and allowed to slowly cool the same annealing technique used with steel (to soften to machine it)?

I know, I know, few really care. Rave on motoman. :laughing:

PS Earlier I said cyl draws heat from head. It may be wrong and the cooler cylinder heat migrates into the head. Who cares etc

Heads on aircraft engines are cast iron depending how lean you run engine the head temp will range from 250 to 450+
Once you land you run engine 1000 to 1500 rpm to cool down. You can watch it cool pretty fast, in time you land till shut down is about 15 min and head temp will be 150 to 180.
FYI flying at 75% power which is max contiounious power setting small piston run at 2300 rpm

Well the cast iron perhaps explains the 500F limit (instead of ? 375F ? for aluminum). I thought some AC engines had al heads?

Today I looked at oil temp gauges available. Seems like they have improved since I put on the Beedee. I saw some stepper motor sweep style with a linear scale out to 320F (more temp points spaced evenly, easier to read) A couple also had LED readout with the pointers. The mix ranged from China at $25 , through straight led digital read around $90 out to fancy race stepper motor units @$200. IMO the Japan sourced (few) and one lone US unit (really??), plus a Taiwan gauge are the only safe bets for lawn mower application (vibration, heat,accuracy). All use a similar sensor which screws into the pan drain plug (adapter required).

More info than requested, right?

I rebuilt Lycoming and Contential 4 and 6 cylinder engines for Piper dealer in Norman, Ok from 88 till 90
I just looked it up the Lycoming 0235 engine heads are cast Aluminum alloy,the case halfs (splits down middle with left & right side) Were Aluminum the jugs are Crome Nickel Molybdenum steel (I just looked it up) so I guess my memory wasn't too good about it being cast iron :confused2:
Oil temp ran about 150 to 180, and max head temp of 500*F is right.
For continuous operation manual says keep head temp between 150*F and 400*F, so it must be the alloy they use in casting that lets temp be so high.

This is a great thread for someone wanting to understand the cooling on air cooled engines !

gainestruk said:

I rebuilt Lycoming and Contential 4 and 6 cylinder engines for Piper dealer in Norman.....
[...]
This is a great thread for someone wanting to understand the cooling on air cooled engines !

Click to expand...

Owning a past close relationship with aerotechs I have always held you guys in high regard (respect)
as at anything above maybe 500', below 60Knots, the last thing anyone wants happening is for those
pigeons to die in their cage!
Yes, I am skerred of Al.alloy anything around Air Cooled so much so that such engines in 'stationary'
use I have always idled down when the load comes off, yer just carnt trust the build...IME.

KK

Still on aircraft...a while back I did read a lot on the small aircraft sites. One engine design had overheat of the valve gear. Finally, they ran an oil jet across the guide/head and did pull off heat (don't remember but maybe 20+ F). Discussion centered on "morning sickness" which is sputtering and missing at start up . Apparently scares airmen and mechanics and can be sticking valves in guides which can lead to bent pushrods. Anyway my Intek only sees a mist across the guides and cannot be a cooling factor. I even doubt there is much if any oil flow back to the sump with the horizontal cyls and rough , blocked passageways. That brings up the question of why a guide seal?

I guarentee if an aircraft engine sputtered at start up that plane would stay on ground till I found out what the problem was, aircraft engines use 2 magnetos one running spark plugs on top of cylinder and other mag runs plug on bottom of cylinder and the bottom one tends to get lead deposits.
On your preflight check you run engine up to 1500 rpm and on your ignition switch it has both, left and right setting
You check left then both then right with a max of 50 rpm drop between the two.
I hear about people using LL100 which is low lead 100, but it has a lot more lead than regular gas you put in your car or mower.
I've had to taxi back to parking and take out bottom plugs and clean the lead deposits off before I can fly, I don't know how the high lead fuel would affect newer small engine, I don't think it would be bad for them but might require more spark plug cleaning.

On the valve guide seals I kinda wonder if that might be a way Briggs is using to make sure a little their no oil change engine uses a little oil by not having a seal so you would need to add fresh oil every now and then ?
I haven't looked at service manual to see what they do or do not have.

<motoman> lost his way so I repost his latest info on the topic.
Following along no worries, just got nothing growing here, need rain ;-)))

KK


Hot day, hot oil

A couple of us were sharing heat readings , but I lost the thread location.
So here it is to find.
Last Sat 96F.
Mow weeds out chute 30 minutes.
Craftsman dyt4000 Intek 24.
*Oil cooler and fan fitted.
*Oil filter 117F
Cooler fitting 189F
Sump drain plug 183F
Rocker cover 210F
Exhaust header413F
Oil temp (liquid) 280-300F
From Beedee gauge . See pics Idling 5 minutes with fan on oil cooler
reduced oil temp 50 degrees F.

*Attached Images
*592.JPG*(103.9 KB, 1 views)
*594.JPG*(98.8 KB, 1 views)

Ok guys, here is my 4th run with different thickness oil (last time, will run this grade from now on)
Outside air temp 83* at start and 87* at finish which is about the same as I've been doing.
This run is with Rotella T6 5W40 full synthetic.

20 min oil filter=153.3*, block=158.0*, drives=119.8*
40 min = 149.7*, 159.2*, 120.2*
60 min = 176.3*, 171.5*, 140.1*
80 min = 173.4*, 181.9*, 130.2*
90 min = 186.9*, 196.8*, 130.6*

Here is a run down from lightest to heaviest weight oil

5W30 synthetic ----------------10W30 Dino---------------5W40 synthetic--------15W40 Dino (these were from memory)
20 min=160.0*,125.7*,100.7*/ 147.9*,151.1*,118.4*/147.9*,151.1*,118.4*/180.0*,142.0*,142.0*

40 min=166.6*,136.7*,114.0*/ 172.0*,146.6*,123.9*/172.0*,146.6*,123.9*/200.0*,155.0*,135.0*

60 min=174.5*,133.7*,117.6*/ 165.3*,141.1*,123.4*/165.3*,141.1*,123.4*/212.0*,168.0*,140.0*

80 min=178.1*,138.0*,121.2*/ 163.0*,144.6*,125.7*/163.0*,144.6*,125.7*/200.0*,150.0*,148.0*

90 min=178.0*,155.6*,128.1*/ 176.0*,170.4*,125.2*/176.0*,170.4*,125.2*/

Looks like 5w30 got hot faster and was hotter than 10w30 Dino and 5w40 synthetic.
The 15w40 Dino ran the hottest.
Now how about someone else trying it ?
I will show temps again with 5W40 synthetic, but I'm not planning to try any other weight.

gainestruk said:

Ok guys, here is my 4th run with different thickness oil (last time, will run this grade from now on)
Outside air temp 83* at start and 87* at finish which is about the same as I've been doing.
This run is with Rotella T6 5W40 full synthetic.

20 min oil filter=153.3*, block=158.0*, drives=119.8*
40 min = 149.7*, 159.2*, 120.2*
60 min = 176.3*, 171.5*, 140.1*
80 min = 173.4*, 181.9*, 130.2*
90 min = 186.9*, 196.8*, 130.6*

Here is a run down from lightest to heaviest weight oil

5W30 synthetic ----------------10W30 Dino---------------5W40 synthetic--------15W40 Dino (these were from memory)
20 min=160.0*,125.7*,100.7*/ 147.9*,151.1*,118.4*/147.9*,151.1*,118.4*/180.0*,142.0*,142.0*

40 min=166.6*,136.7*,114.0*/ 172.0*,146.6*,123.9*/172.0*,146.6*,123.9*/200.0*,155.0*,135.0*

60 min=174.5*,133.7*,117.6*/ 165.3*,141.1*,123.4*/165.3*,141.1*,123.4*/212.0*,168.0*,140.0*

80 min=178.1*,138.0*,121.2*/ 163.0*,144.6*,125.7*/163.0*,144.6*,125.7*/200.0*,150.0*,148.0*

90 min=178.0*,155.6*,128.1*/ 176.0*,170.4*,125.2*/176.0*,170.4*,125.2*/

Looks like 5w30 got hot faster and was hotter than 10w30 Dino and 5w40 synthetic.
The 15w40 Dino ran the hottest.
Now how about someone else trying it ?
I will show temps again with 5W40 synthetic, but I'm not planning to try any other weight.

Click to expand...

W0W..!.. I saaaaaay W0W.
U set a high benchmark, brother!
It needs to rain here but meanwhile I am:ashamed:

Good work. The thinner oil circulates faster and (hopefully) unloads heat faster . But where it unloads, the question. Without an oil cooler it only unloads on cyl walls and sump casting. Casting sits on a big gauge steel platform (on al feet -at least on my Intek/Craftsman). Once heated this big slab of steel will not cool down quickly. Guess I should take a reading of the steel platform to compare with the sump.

OK, (choir disregard this old familiar theme)... The aluminum air cooled heads as critiqued by an airplane guru...(paraphrase): The aluminum heads have an extaordinary task. Before machining they are heat treated @ 1000F and quenched to T6 (hardness). During operation the exhaust side of the head is extremely hot while at intake fuel and cold air incoming create a huge temp difference. Heads are subject to cracking if cooled too rapidly . This is the cause of valve seat problems. Over temp problems start at around 325F and (other sources ) soften at 390F. This causes valve guide problems. On the subject of valve guide seals...while oil flow can aid cooling , seals may be necessay to stop excess oil at the valve and guide interface. The high temps can cause coking (deposits) which can cause sticking of the valve, bending the pushrods.

Ideas for owners manuals (in my dreams)..."CAUTION , if dash oil temp gauge is over 240F do not shut off tractor. Go to shade and idle until oil temp reaches 240F or below. Never wash or cool warm engine with water." I know, I know, owners don't always even keep oil level, much less watch a gauge. Maybe if they were flying. Fantasy time for longer tractor life.

Edit: Add to owners manual. "Avoid any grass bagger system. Added weight and engine load drives up engine temperature . Use a sweeper."

Yep paying attention to gauges would be a challenge for some owners, BUT it takes on a whole new meaning when you are 3000' above ground and your life depends on keeping track of how engine is doing

Adding my .02 cents to this.
Bride mowed the yard today and I recorded the following temps using a Cen-Tech model 96451 Infrared temp gun, I shot the temps from about 3 feet away from each point.
Air temp was about 65 F at time of mowing.
Before start after 10 minutes of mowing at shut down (20 minutes after start)
Oil Tank 79 F 147 F 156 F

Oil drain plug 78 F 162 F 198 F

Oil filter 78 F 164 F 190 F
(center of bottom)

small X is the aim point center of filter and the Hex bolt to the right of filter are the aim points



Don't know why the chart keeps collapsing on it self.

I pointed my gun at middle center of front of block and center of oil filter like you, looks like you are getting about the same readings as me.

I had same problem with charts, had to try a couple of times till I got it all to line up.

Thanks for the added data. I am using a KE thermometer which allows a person to place the little round bead pickup directly on the the metal. Seems like the one reading that is similar so far is the sump plugs @ 180-195F in outside temps of 60-90F + Keep it coming. Especially head temps if possible.

All interesting folks but do any of you actually know what the ideal operating temperature of the oil or the engine is ?
In general a thinner liquid will transfer heat a lot faster than a thick one which is why you quench alloy steels into oil or in some cases molten salt baths.
Far more important than the temperature of the oil is its film density and strength as the film between the rod & journal is all that stops the engine going bang, big time.
As an aside the local blue smoke mob down here uses a cast iron crank & barel on the Poewertorque engine.
Every time a revision is made, they remove remove cooling fins as better methods of thermal evaluation and in particular thermionics has revealed that the barrel had too much cooling which was causing local cold spots.

Way back when I was young & stupid but of course knew more than all the professional engine designers , I fitted oil coolers to all my bikes as that was very fashionable particularly if you thought you were a red hot rider ( wern't we all ? ).
Anyway as the years went on I found myself keeping company with some people who actually knew about oils and after a few visits to the test labs, all the oil coolers came off, and suprise , surprise, the bikes actually went better without them.

A big big problem with infrequently used engines is moisture condensation in the cases and your oil must get hot enough to evaporate this water.
A low viscosity oil oil will transfer heat fasther than a high viscosity oil but the lower oil has a substantially lower film strength so must be pumped a lot faster in order to maintain a boundry lubrication on moving parts.
One of the main reasons Honda small engine start so easily is the fact they use 10W 30 to 10W 50 oil and at ambient temperature the oil offern next to no resistance. It also has next to no lubrication.

So whole what you are doing is interesting, don't be fooled by the cooler must be better camp, often it is not.

Professionals who see scores and scores of damaged engines , please respond. From this home hobbyist it appears that the low end air cooled engines are most all on the edge of overheat. By that I mean driving the head into 390F + territory where the alloy softens. The liquid oil probe/gauge on my Intek will (too) quickly go to 290-300F, but the oil cooler pulls it down to about 240F if 5 minutes. Someone suggested months ago that factory reps do not want oil to exceed 270F . Seems to me it does in many cases.

Do commercial engines have oil coolers? Bert, how 'bout flashing the sump plugs on the units you see. So far the whopping big sample of ?3? which we have shows these plugs at around 180-195F. IF (big if) the difference is 50F for the liquid oil here is a rough approximation of oil temp for those who do not have oil temp gauges. How many forum inquiries per month on "overheating," valid or not? Will these "overheating" low end rigs last longer if heat and oil level is controlled? I think the answer is yes.

My Briggs came with a oil cooler.
I change the oil every 100 hours. As recommended for this engine.

Does it make the engine last longer?
I do not know yet. Only at 1247 hours.

Carscw said:

My Briggs came with a oil cooler.
I change the oil every 100 hours. As recommended for this engine.

Does it make the engine last longer?
I do not know yet. Only at 1247 hours.

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Not sure if it helps LOL, I'd say it's done pretty good with 1247 hrs :laughing:

Can you get some temps posted running at full temp of oil cooler, filter and block say at the drain plug ?

gainestruk said:

Not sure if it helps LOL, I'd say it's done pretty good with 1247 hrs :laughing: Can you get some temps posted running at full temp of oil cooler, filter and block say at the drain plug ?

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I don't have a temp gun.
Never had a need for one.
It must help some.
The oil does not start to change color till around 60 hours.
But my Koehler pro's oil does not change color till around 50 hours. Without a cooler.

I run royal purple 20w 50 in everything. Because I got a pallet of it at a auction.

I very rarely see an engine suffering from strait overheating.
Most common failues in the order of occurrenc at my shop.
1 by a very long way, old engines siezed from lack of oil ( around 6 to 7 per season )
2 new engine ( OHV ) seized from running along a slope and again. oil starvation . (4 to 5 usually)
3 Inteks with blown head gaskets, now I do not pull the engine down to look at the inside of the piston to see if it has been running too hot but no signs of overheating at the top end or piston crown. ( 4 to 6 each year )
4) Courages with the infamous Kohler crack (2 usually)
5) Courages with loose top plate bolts causing seizure 1 or 2
6) courages with loose bolts not blown from lack of oil 1 or 2
The mowing season around here is 30 weeks / year
Mid summer temperatures 90 to 100 ( F )
Average block for my customers would be about 2 acres
About 1/3 of my customers have a bio cycle dunny so lawns get a lot of nutrient rich effluent and thus glow thick & fast.

Please note I am not trying to poo poo what you lot are doing, I find it most interesting.
I used to be a foundry metallurgist so calculating internal metal temperatures based upon an external reading was stock and trade for me.
It is a lot more complicated than most would think & I had a state of the art thermionic remote pyrometer which measures the colour of the heat radiating out of the metal, not just the infra red heat and the two can be a long way apart.
All metal oxides are refractory, including aluminium and the thickness of the oxide can make a very large difference to the readings.
Other things that will introduce system errors are variations to the viewing angle and the distance the readings are taken from. the air temperature , humidity wind speed.

If you want to get readings that are consistant so you can evaluate the effect of using different oils or other variables you really need to take contact readings with glued on sensors.
You also need to take your readings on days with the same relative humidity and air temperatures.
An internal oil reading using something installed into the drain plug and/or dip stick tube will be useful as that will allow you to correlate external metal temperatures to internal oil temperatures.
A long meat thermometer mounted through a small hole in the dip stick would work .
You used to be able to get a similar device for OIF motorcycles which replaced the original dip stick.

I have a husqvarna with a 26hp kohler engine-2015. Do you know where to get a temp probe, analog or digital readout gauge, and where to locate the sensor to give me a liquid temp reading like an automobile? I mow over 5 acres and usually stop halfway and open the hood to cool off the engine. I mow heavy stuff so I would like to know the temp of the engine so it does not look like thermite was poured on it. thanks alot!!

Look by your oil filter and see if it has a plug in the housing, if so you can take it out and go to auto parts store and see if they have a sending unit that will fit, the gage needs to go up To at least 250*

I was using a small temp gun that fit in my pocket and it was easy to turn around and shoot temps without shutting down or getting off my Z turn.

Yes, auto stores do offer oil temp gauges with probes. When I had my Intek apart I looked carefully for a safe place on the aluminum pan to drill and tap and decided it was too risky so I settled on the sump plug. Those with a drill press and some experience can center drill and tap the sump plug to 1/8 NPT without drama. Or you can find a nice brass plug with a 1/8 NPT hole already in place. I think it was Lowes plumbing in a plastic baggie, but not cheap, $6 + , I think. Going this route will slow down oil changes a bit because the electrical spade or round contact is held on to the probe with a small machine screw which is removed each change, but small price to pay.

If installing a oil pressure gauge my experience with mechanical senders has been poor. Those are much cheaper, but a probe placed in the oil filter housing caused me much grief as I could not find a setup which could reduce vibration enough so it would not dislodge the press-on plastic line routed to the dash gauge. Very messy. The electric sender on mine has worked without a problem for years, but is more expensive. You may have to drill and tap the driver side of the oil filter housing. Don't remember but perhaps 1/2 " NPT. It is not rocket science but just drill where you can expose the electric can probe to oil pressure.

I think many auto stores have a selection of gauges which should hold up. I once used JC Whitney with good results from Taiwan stuff. Not long ago I looked at the digital read outs. They are appealing and some very trick , but most appear mainland China which scares me . Upper range is great included data logging reports for PC review etc, but VERY expensive. I made an oil tube sensor for my KE thermometer and it worked . The results are taken from liquid oil not far from the oil sump plug. I got tired of oil splatter on my face and have not used it in a while. I think the readings were slightly below those of the sump plug probe. Bla bla bla:laughing:

And while adding some more operator information might be useful, if you actually look at it regularly and notice it is outsie the normal operation range, they are really just worry boxes.
REmoving the cowls at regular intervals and cleaning off the dirt dust & debris would be a more worthwile use of your time.
All mower companies test the engines for running temperatures in extream conditions as do the engine suppliers.
I have never seen a mower with overheating problems that was full of oil with a clean engine block.
Now if you want to tinker then look at moving all of the stuff that makes it difficult to remove the covers to access the bare block so it is quick & easy to do.

On a few mowers I have moved the Baldwin type air filter to the ROP, bolted the finger guard to the cowel, cut down the debris screen to pass strait through the hole in the cowel and moved the fuel pump to bolt onto a spare mounting hole on the block.
On some I replace the cowel mounting bolts with wing nuts so the cover can be whipped off in a few minutes.
So now it is simply unscrew the mounting bolts, unplug the rectifier and the cover comes strait off. A quick blast with the air duster and wack the cover back on.
Then instructions for the customer to clean it weekly which most do since a 2 hour job needing 6 tools has now become a 10 minute fingers only job so it gets done.

Honestly I love gauges and I worry too much. It is like a manual car with no tach...my early cars had that and their automatic counterparts had a tach....whatever. I clean the heatsinks and shrouds, but I still want to know the temp as I mow a lot in one session. Just trying to prolong an investment. How do you determine the optimal temp of the engine oil at full throttle while mowing?

Berts and IL ENG and I have a long running conversation over heat and the low end ac engines. Once again let me state I am ref point only when it comes to statistical fact as I have only owned one mower , the Craftsman dyt 4000 with Intek 24. You should never predict a political outcome here. Now stated, any universal truths from my babbling may be suspect.....BUT I will state adamantly what I have found with my unit. That under load in summer the oil temp runs up fairly quickly to 250F (which would be ok if stablized there), then to 280F regularly as the 3 bin grass containers fill up. At ambient here at around 85F I see indicated 290F-300F on the Beedee gauge and have posted pictures in this forum. When around 300F I stop for 5 min and let the fan run which reduces the oil temp 50F.

IL ENG has suggested my unit is unusual or needs rejetting. I am at 1800 ft, but plugs read ok , never burnt a valve. Yes I am a tinkerer and have enjoyed the gauges. Again I say an OIL PRESSUE gauge is useful and not a worry. Once accustomed to its reading it can suggest if your oil level is low-jump off immediately and check the stick.
The Intek runs 35-40 psi hot after 12 years on 1 acre mowing and hauling, 5W-30 Mobil 1. An owner running one of these big box unit SHOULD worry about it self destructing. I have said an ideal gauge would include a rubber hammer to bonk the owner on the head if necessary. A cheap red light can be easily rigged up with or besides the gauge.

The oil temp gauge speaks for itself. The sensor soaking and running in liquid pan oil is very enlightening. I have referee tested the gauge with my KE thermometer and did find it a little high. So perhaps indicated 300F is "only" 285F. Who wants that? Why do the better class mowers have oil coolers? Peace and brotherhood.:wink:

Using a temp gun the most I ever got was 212* at oil filter, so it's hard to tell if that is wrong I would need to use motomans probe to see what I got.

I would say what ever you get go out and get test temps just running and then mowing, that way you can see if it suddenly goes up you know there is a problem and need to shut down to cool.

I have faith in hand held heat temp gun and use it to make sure I don't go over say 215*
I do mow less than ingigo my yard takes about 1hr and 20min start to finish. As much as you are mowing ingigo I would suggest you get something to check temps, also every month or sooner take shroud off engine and make sure engine Finns are staying clean also every time you check oil make sure screen is clear of debries so air can freely flow thru engine, I would also keep oil at full mark all the time, the oil helps cool and more you have the better it does.

motoman said:

Berts and IL ENG and I have a long running conversation over heat and the low end ac engines. Once again let me state I am ref point only when it comes to statistical fact as I have only owned one mower , the Craftsman dyt 4000 with Intek 24. You should never predict a political outcome here. Now stated, any universal truths from my babbling may be suspect.....BUT I will state adamantly what I have found with my unit. That under load in summer the oil temp runs up fairly quickly to 250F (which would be ok if stablized there), then to 280F regularly as the 3 bin grass containers fill up. At ambient here at around 85F I see indicated 290F-300F on the Beedee gauge and have posted pictures in this forum. When around 300F I stop for 5 min and let the fan run which reduces the oil temp 50F.

IL ENG has suggested my unit is unusual or needs rejetting. I am at 1800 ft, but plugs read ok , never burnt a valve. Yes I am a tinkerer and have enjoyed the gauges. Again I say an OIL PRESSUE gauge is useful and not a worry. Once accustomed to its reading it can suggest if your oil level is low-jump off immediately and check the stick.
The Intek runs 35-40 psi hot after 12 years on 1 acre mowing and hauling, 5W-30 Mobil 1. An owner running one of these big box unit SHOULD worry about it self destructing. I have said an ideal gauge would include a rubber hammer to bonk the owner on the head if necessary. A cheap red light can be easily rigged up with or besides the gauge.

The oil temp gauge speaks for itself. The sensor soaking and running in liquid pan oil is very enlightening. I have referee tested the gauge with my KE thermometer and did find it a little high. So perhaps indicated 300F is "only" 285F. Who wants that? Why do the better class mowers have oil coolers? Peace and brotherhood.:wink:

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Joe average will only look at the gauge when the mower starts to check it is working then ignore it till the engine starts to seize.
Ask any one who services engines about how many low oil seizures they get from a mower with no oil leaks.
I bought 200 keyrings when I took over that are 3" round so they fit over the dip stick and when I deliver a mower that is where I put the key and encourage owners to keep it there so it "won't get lost" and "will always be handy"
The little ploy seems to be working as serial engine seizers have not been back for a while.
Next trick will be to print the tag on cloth so they have something to wipe the dip stick on.
At least once a week in season I get a desperate " I got off the mower to....... and now it won't start" and these are always mowers with oil sensor cut outs hooked into the starting circuit.

Now if you enjoy doing it then more strength to your arm but get on to the oil company and check what is the temperature range of the oil you are using.

"the engine seizers"..I love that one. Oil operating ranges have been beaten to death here and everywhere. It's the cooling thing.

yes gaines. I always stripped my Briggs down and busted out the air compressor to really get in there, and did it often. the air cleaner it key too, with the right amount of oil on the prefilter. with hydrostatic you can slow down to put less load on the engine without altering the throttle. The Kohler I have now has no pre filter and seems more modular...less tools. I do not like that but I have not had a problem working with it with at all, it runs cool. I think the key is like the transmission , a fan and good airflow. I would love a little fan under my hood...until then I just find shade and open the hood.

The fan I put on my Intek 24 rig is off a Nissan and does not cool the oil cooler during movement, but does quickly draw off 50F at idle, no load. Better fans are out there and quite compact. I have seen that several of factory oil coolers are without fans, relying apparently on semi static air circulation . We know from car use of trans coolers a good blast is required during operation to work well.

how well does anyone think those fans on the transaxle do much?

Here's an idea I floated a while back that many of you are familiar with. The tempil stick-a propriety name for the temperature crayon used by welders. You can get these in a wide range of temperatures for around $10. They are accurate to 1%. To use just draw a little line on the metal surface and watch if it melts. If so you are at or above the dedicated temperature. I would buy one at around 310F to check on head temps away from the exhaust header (s).

Oh...BTW you will look very natty as these come with a clip and can be worn on a pocket protector for that final touch. Bert, I believe you should attach one to the "engine seizer's" rigs along side the red tags on the dip stick tubes.:laughing:

I got a set of them some where, haven't used them since I got the Dillon gun
OTOH profit margins are not quite that high so we might leave it at a 54c key ring.
I have noticed some green, red or purple dollops of what I originally thought was paint on all the new Briggs engine I have fitted this year and now you have me thinking as it was on the same place on the head bolts.
So maybe B &S have decided to fit some tell tales on their engines.

the dollops...verrrry interesting. So if a dealer sees melt he will check for rodent nests, weed clogging and then......da da.. will immediately write a big check or replace the offending equipment.


An aside Bert...I just read about Australia's water. Seems like you should buy up some rights and stop getting callouses wrenching...

ingigo, why not take a reading with the fan and then one witihou...assuming you would not damage anything

Tempil stick! What a genius idea. Keep it simple stupid technique, love it. I am getting those as soon as I can! Thanks motoman!

I am trying to find a way to better see the gasoline level in the small opening with the hash marks located below the front of the seat. Most mowers use them now as it is just an opening to see the bottom of the gas tank, telling you when to stop mowing and go home. Anyone have any tricks? Can I dye the gasoline with food coloring or it there in any thing on the market I could use? It is not a huge issue but would be nice to just glance at the level instead of stopping to stare at it. Thanks!

Glue a plastic mirror on the mower so you can see it from the seat.

Seems like I remember someone installing an auto type gas gauge a while back.

ingigo said:

how well does anyone think those fans on the transaxle do much?

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the people that build the hydrostats think they do. It comes up in my hydrogear update every year about broken blades and we are always told if they could operate properly with one less blade they would build the hydro with a fan with one less blade.

An auto gauge...how did they route it thru the tank? I love to know the temperature best, because I have no means of checking temp besides the tempil sticks.
That takes too much time, I have 2 big nice round gauges on the tractor...amps and an hour meter.
I think there are more important things to monitor, but that takes dreaded sensors the company has to buy. I miss the older tractors in many ways like that.



I have never seen a broken blade and why would one extra fan blade on the transaxle matter much at all? I love a 3 blade deck if you know how to arrange the blades and keep it clean.
I just do not understand your comment ILENGINE. It seems even the mid size, larger tractors are going to hydrostatic now.

I think if you could take heat images of the surface of the transmission you would see heat layers kind of rolling off which a fan clears away.


The tempil sticks are apparently widely used for temp readings on transmissions.

ingigo: Here is my sermon on gauge installation: The oil temp gauge installation is not that difficult, although it would seem so for a newbie. You already have a hole in your dash--take out the hour meter. The hole is probably 2 to 2- 1/8" dia which is standard for many gauges. That hole will mount the oil temp gauge which will be held in by two thumb or hex screws backside. At the oil pan you have a drain plug. You buy an equivalent plug at Lowes that also has a 1/8 npt (the thread) hole already in the center of the drain plug. Screw the oil temp sensor into the new drain plug. Screw the drain plug into the pan (the gauge sensor will then sit in oil). WIRING: the little kits show where to wire. There will be a 12volt contact (borrow 12V from the existing tractor wiring plug-(if afraid of this have some do it for you) , probably a ground (frame) contact, and the contact from the gauge to the little contact which sticks out from the sensor you screwed into the drain plug. Aside from a little fiddling with the insulator washers on the sensor screw, that's it.

Yes, hour meters are useful. If you have a hole saw in 2" dia and enough room on the front side of the dash , cut out a new hole for a 3rd gauge. Do not cut without making sure you will NOT ruin existing wiring. My Craftsman has plenty of room for 2 gauge holes.

If you are still leery that is ok. Any aftermarket auto or motorcycle shop could make this installlation in about an hour. The kit probably $50. The labor , maybe an hour for a pro. If you are a newbie give yourself a day. sounds like you will enjoy such a gauge.

When (if) my Craftsman ever dies I plan to do a pic installation and will share. Again, way more that anyone asked for.

BTW Why is a sensor "dreaded?" Also is IL ENG blades the fan blades, not the cutting blades?

Thanks motoman!

A "dreaded sensor" means it is very easy to install an electrical gauge an hour meter, but fluid temp sensors are "dreaded" by the company because they cost more both parts and labor. the other ? is that I was talking ONLY about the transaxle cooling fan. It was stupid of me to think 1 less blade would not matter. I have a lot of aeronautical background knowledge and any imbalance reduces cooling and the thrust of air dramatically. I apologize for this. Balance those mower blades too!

I can do everything to install the oil temp gauge motorman, but I have one BIG question. The 1/8 tapped hole in the new drain plug. Will the sensor screwed into the hole leak oil? should I put some high heat threadlock on the threads? There is a separate valve to drain the oil, so I have 2 low oil plugs waiting to be tapped.

ingigo, Both the original oil drain plug and the hole for the oil sensor are National Pipe thread (all I have seen). This means the threads are cut tapered so at a point there is interference between the mating threads of the oil plug threaded hole and the sensor OD threads (I know you know this, partially being said for other newbie viewers). This interference "mostly" results in a leak proof seal when torqued with a short handled wrench (guessing...up to 35 lb ft?). There are times when such pipe threads will leak under pressure where sealer or teflon tape can be used. Since this app only sees crankcase pressure I have not had a problem just metal to metal . (Everything else leaks, not the plug :rolleyes) The Lowes plug is brass and I think the sensor is steel. Sounds like you will have a carefree set up that will not require disconnecting the sensor wire for oil drain. I simply place the brass Lowes plug in a vise and tightened the sensor down. For oil change that assembly is disconnected from the send wire and the big hex plug removed. Again if a person does not want to buy the ?$5 plug is is fairly simple (with a drill press) to make the hole in the oil plug and (carefully) tap the 1/8NPT. As for expense to the mfgr...if we pay $50 at retail the parts gotta be half that for a mfgr. But of course there is a labor charge, drawing changes, manual language ,,,on and on. Plus as the pros here point out mfgrs probably simply gave up cause like Berts' customers , the "engine seizers," most won't read the guages. I have watched mine and treated the lowly born Craftsman Intek like a queen, and so far have only caught her cheating once.

Wow, that's good info and a lot of it.
How much $ does the pre tapped oil plug run? I do not have a drill press anymore, or a tap set.
Once installed the plug will never be removed, so I can permanently seal it. I think Teflon tape would just melt quickly.
I would have to use high temp red Loc-tite. What else it recommended to seal a hot threaded connection?

Just try metal to metal to start. I have had the cheapo HF teflon tape hold up to hot oil temps. Go to lowes spcialty plumbing pegboard with baggies. I think you will find the fitting around $5. If you get a bottle of lock tite you will pay a lot and it will soon expire its shelf life.