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Has anyone noticed increased oil consumption in their push mowers while using 10W-30 rather than straight 30W? I am a stickler about using only 5W-30 in my auto engines but when it comes to small motors I really don't pay much attention to which one I use, between the two others. (10-30&30) The manuals caution not to use 10W-40 and I have never understood the reason why that weight would be any different from 10W-30, seems like it would better protect an engine in really hot weather.

It's not the weight. It's the API rating. 10W40 does not meet the requirements for small engines. And SAE 30 is on the way out as being recomended. 10W30 & 5W30 are the recomended oils now. The reason is the additives and how well they lubricate.

indypower said:

It's not the weight. It's the API rating. 10W40 does not meet the requirements for small engines. And SAE 30 is on the way out as being recomended. 10W30 & 5W30 are the recomended oils now. The reason is the additives and how well they lubricate.

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The newest push mower I purchased last summer, with a Briggs 6.75, has an engine manual included that says below 40 degrees 30W may cause hard starting, but that weight may be used up to and over 104 degrees, and 10W-30 can be used in temperatures as low as zero, but use in temperatures about 80 degrees may cause increased oil consumption, with a ceiling illustrated of a naximum of about 98 degrees, and for 5W-30, the temperature range is very narrow, 40 DEGREES AND BELOW ONLY. (emphasis added) It does say any motor oil with an API rating of SF, SG,SH,SJ or higher may be used.

I have NEVER seen 5W-30 okayed for use in any air cooled small engine except for wintertime temperatures.

Regarding multi-vis oil,

The first number (10w in 10w30) is how well the oil flows cold. (it will flow the same as cold 10w oil). The second number is the hot flow. You don't want to use 5w30 in a push mower, it'll just burn up, because it's so thin.

Straight 30w will be thick as honey when it's really cold (that's why it isn't reccommended for winter use), but thin right down at operating temp. The advantage, as you saw, is that it'll take a lot more heat.

10w40 is too thick at temp to lubricate properly and help with heat dispersion. Air-cooled engines are picky like that.

I always use 10w30 in the winter in all my stuff, (but my car) and straight 30w B&S oil in the summer. When the temp doesn't get below 60 at night, you don't see a lot of advantages to multi-vis.

Hope that answers your question.

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

ILENGINE said:

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

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True. But, if it's an older engine, the toerances aren't as tight, and 5w30 will tend to be way too thin. Also, A slinger system doesn't like wimpy oil, whereas a full-pressurized system can get the oil to the critical bits using thinner oil. Also, older B&S used solid lifters, and a thicker oil will keep them from clattering in the heat.

I guess it depends on the vintage of your push mower, JD.

ILENGINE said:

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

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The manual I got my info from does show 5W-30 synthetic in the chart, but nowhere in the written information (a quarter page) does it say a word about that oil.

twall said:

True. But, if it's an older engine, the toerances aren't as tight, and 5w30 will tend to be way too thin. Also, A slinger system doesn't like wimpy oil, whereas a full-pressurized system can get the oil to the critical bits using thinner oil. Also, older B&S used solid lifters, and a thicker oil will keep them from clattering in the heat.

I guess it depends on the vintage of your push mower, JD.

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My pushers, the oldest ones are 2004-05 vintage, recommended grade is straight 30W bit 10W30 is the alternate, that's why I was wondering about oil use because I pretty much use that multigrade.

Like I use...

10w30 is the reccommendation for cold weather use, and Straight 30w is for the summer. I always use B&S 30w, because it has a lot of additives to keep 'er goin longer.....

Briggs and Stratton has approved the use of 5w30 synthetic oil in all of there engines. Winter or Summer for all temperature ranges. The 5w30 synthetic wasn't approved by Briggs until a couple of years ago or so and is retroactive to older engines.

ILENGINE said:

Briggs and Stratton has approved the use of 5w30 synthetic oil in all of there engines. Winter or Summer for all temperature ranges. The 5w30 synthetic wasn't approved by Briggs until a couple of years ago or so and is retroactive to older engines.

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I'm still leery of it.......especially in a worn engine. I'm not a fan of the rod being OUTSIDE the block....! Sounds like B&S wants to sell more engines......LOL

I have been running synthetic 5w40 in all my engines for many, many years now, in all my engines, gas and Diesel... large and small..
For the last couple years it's been Rotella T6, 5w40, annual oil changes... :smile:KennyV

KennyV said:

I have been running synthetic 5w40 in all my engines for many, many years now, in all my engines, gas and Diesel... large and small..
For the last couple years it's been Rotella T6, 5w40, annual oil changes... :smile:KennyV

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Kenny, I have considered using synthetic oil but the cost scares me off, I generally change the oil in my push mowers just before I store them in the fall, and then again mid mowing season in late July, when I also resharpen the blades. Since I have to tip the push mowers on their side to remove the blade to sharpen it, it's not big deal to drain and change the oil at the same time. Since the mowers have no filter, it's easy to do the oil changes.

I know synthetics are made to prolong oil change intervals but I'm sticking with conventional oil for now.

my gas mowers get very little use... And they have drain plugs.
So in April I will put forks on my loader and lift them up, drain oil remove and sharpen blades...

every thing gets a change at the same time... easy to remember... :smile:KennyV

KennyV said:

my gas mowers get very little use... And they have drain plugs.
So in April I will put forks on my loader and lift them up, drain oil remove and sharpen blades...

every thing gets a change at the same time... easy to remember... :smile:KennyV

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I have 5 pushers, ages dating from 2001 to 2010, and NONE have drain plugs, (that I know of) the engine manuals all say to tip the mower on it's side to drain. I wonder sometimes if they recommend that because the mowers don't have drain plugs, or if they think fewer people will injure themselves messing around draining oil from underneath. Later today I am going out and check to see if any of my mowers has a drain plug...

Hmm, just found the manual for the oldest one, a Craftsman...manual shows a drain plug in the engine parts diagram but same manual recommends tipping to drain oil....:confused2:

There is nothing wrong with tipping them over to drain... Many small engines have the drain plug on the side right below the fill port... I just have the forks on at the time for lifting the decks to sharpen or replace blades... & I can bring everything up to eye level ...
:smile:KennyV

KennyV said:

There is nothing wrong with tipping them over to drain... Many small engines have the drain plug on the side right below the fill port... I just have the forks on at the time for lifting the decks to sharpen or replace blades... & I can bring everything up to eye level ...
:smile:KennyV

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Kenny, I cannot frickin' believe this but out of five pushers, two of which are Yard Man, one is Craftsman, one is a Brute, one is a YardPro (Husqvarna)...ALL OF THEM HAVE A DRAIN PLUG....!!!

The drain plugs are shown in the parts section, but in all five manuals, NONE OF THEM say one word about the drain plug for oil changes, they all show illustrations and have instructions about draining the old oil by tipping the mower on it's side. On the Yard mans the drain plug is a recessed 3/8 inch drive socket plug, on the Brute and YardPro you have to remove a part of the front drive belt shield near the blade to access the drain plugs. Next time I change oil on my pushers I am going to lift them up onto sawhorses and see how easily I can access the plugs. I made one pair of sawhorses really high for when I have to work on mowers, not as fancy as a FEL and forks but they serve the purpose.

JDgreen said:

Kenny, I cannot frickin' believe this but out of five pushers, two of which are Yard Man, one is Craftsman, one is a Brute, one is a YardPro (Husqvarna)...ALL OF THEM HAVE A DRAIN PLUG....!!!

The drain plugs are shown in the parts section, but in all five manuals, NONE OF THEM say one word about the drain plug for oil changes, they all show illustrations and have instructions about draining the old oil by tipping the mower on it's side. On the Yard mans the drain plug is a recessed 3/8 inch drive socket plug, on the Brute and YardPro you have to remove a part of the front drive belt shield near the blade to access the drain plugs. Next time I change oil on my pushers I am going to lift them up onto sawhorses and see how easily I can access the plugs. I made one pair of sawhorses really high for when I have to work on mowers, not as fancy as a FEL and forks but they serve the purpose.

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My snapper has "oil fill/drain" labelled on the dipstick, but there's a plug underneath that's easy to get to. I always use that.

twall said:

My snapper has "oil fill/drain" labelled on the dipstick, but there's a plug underneath that's easy to get to. I always use that.

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This is the straight scoop --- air cooled engines have hot spots usually near the exhaust valve on the engine head. These hot spots will break down the VI ( viscosity index ) improvers over time. The byproduct of this chemical breakdown is a type of varnish, which is not a lubricant. To make a conventional ( not synthetic ) 10w30 oil it would use a 10 wt. base oil, detergent package, and VI improver. This oil will flow like a 10 wt. oil at low temperatures and lubricate the load beering surfaces like a 30 wt. when at operating temperatures. When the oil comes in contact with the hot spots the VI improver starts to break down until the oil becomes a 10 wt. oil. A 10 wt. oil will not give the engine adequate boundry lubrication and clearance to the bearing and crankshaft thus the connecting rod breaks and it's by-by engine. Period. A 10w40 oil is the same formula 10w30 with more ( 3 - 5% ) VI improver.
A straight 30wt oil contains no VI improver, therefore no breakdown. However the oil will act like molassas if you try to start an engine on a cold winter day. Synthetic oils use ultra pure components that require a small amount of VI improvers to meet the 10w30 grade. Also higher horsepower air cooled engines use pressurized lubricating systems which have larger oil sumps for better temperature control.
The bottom line -- use straight ( conventional ) 30 wt , 40 wt , or synthetic 10w30 , 15w40.
Do not use a conventional 10w30 ,or 10w40
The cost of the oil is a lot less than replacing the engine!!!

10w40 is more prone to break down against the high heat of an air cooled engine, and turn into an engine destroying goo.

Never use 10w40!

Craftsman owners manual allows 5w-30 which I use. It throws out a little which is good in my opinion. Interesting what JD says about the hot spot near the exhaust valve on AC engines. I have (in this forum) attempted to measure the temp of the exh valve guide casting on my 24 Intek, but could not get a good heat transfer to the K probe. I have measured 312F with a head probe under the spark plug. My theory (forum browsers tune out) is that the "creep" temp of 390F was reached on my rider which pushed the exh guide into the head. Since adding gauges and an oil cooler I know when it's too hot to keep mowing (sump oil 290-300F).

Oil is like politics...but my read says go with thinner oil for cooling as there is more throughput per unit time. The Intek holds 30PSI at indicated 290F oil, but is not runaway (it stabilizes with the cooler). The read also said the additive pak that goes away with heat/time affects the thinner and that is visible by the time I change the oil (5W-30 Chevron) which is much thicker than new. Perhaps it is the additive pak people are referring to when they inevitably say "breakdown" without defining it.

Don't know about the politics or semantics involved, but a cooked engine destroyed due to 10w40 breakdown is one that you won't forget.

The engine usually has adequate oil level, and oddly enough either the rod or the lower bearing is the one that seized. The messy goo in the crankcase is hard to remove, straight gas and brushes usually is the best, but why? As the bottom sump/bearing is toast as well as the crank.

The oil industry may have improved the 10w40 oil in the last 10-15 years, while they were not throwing the world in a recession {that approached
the "Depression" word}, and if they have, I don't know about it.


But 10-20 years ago, 10w40 multi-viscosity breakdown was a common
problem........

So I still advise against it.

fish, definition , please, of "breakdown"

The misinformation is only going to be exceeded by decades Old, partial information...

Breakdown occurs when the life span of the oil is used up it loses lubricating properties no? I've never heard of oil sludge unless someone hasn't changed oil in like 20 years...

Fish said:

Don't know about the politics or semantics involved, but a cooked engine destroyed due to 10w40 breakdown is one that you won't forget.

The engine usually has adequate oil level, and oddly enough either the rod or the lower bearing is the one that seized. The messy goo in the crankcase is hard to remove, straight gas and brushes usually is the best, but why? As the bottom sump/bearing is toast as well as the crank.

The oil industry may have improved the 10w40 oil in the last 10-15 years, while they were not throwing the world in a recession {that approached
the "Depression" word}, and if they have, I don't know about it.


But 10-20 years ago, 10w40 multi-viscosity breakdown was a common
problem........

So I still advise against it.

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I agree. I can't remember exactly when in the past, but GM claimed that they would not honor warranties if 10w-40 oil was used.
Bruce

exotion said:

Breakdown occurs when the life span of the oil is used up it loses lubricating properties no? I've never heard of oil sludge unless someone hasn't changed oil in like 20 years...

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It was the viscosity improvers added to the oil to get it from the 10 weight up to the 40 weight when hot that would break down in extreme conditions and cause sludge, varnish, and loss of protection. That's why synthetics would withstand heat better, they required less viscosity improvers to reach that viscosity spread. Generally speaking, the closer those numbers are to each other, the more resistant they are to shearing and breakdown, for example, 5w20 is a thin oil, but rarely shears down out of spec. Same with 10w30. But take a 5w30, and by the end of an oil change interval, it might shear down to a 20 weight oil anyways. Technology had improved so much in the past 15 years or so that this isn't really much of a problem any more. I've been running regular oil in my stuff for the past three years with out a problem now and in fact, i'm using Valvoline maxlife 10w40 in my lawnboy right now and it hasn't blown up yet and honestly, unless your using a more expensive "boutique" oil like amsoil or redline, your "synthetic" oil isn't really a true synthetic anyways, just a highly refined group 3 or 4 dino oil. The big companies like Pennzoil or Valvoline used to make true synthetics until everyone caught on to what castrol was doing with their syntec line, there were lawsuits involved and the government wound up ruling in castrols favor, now no one makes a true synthetic since honestly, the higher end Dino base oils work nearly as good,b and its cheaper for them to produce.

Sludge is also formed by insufficient operating temperature. Strange I would talk about not enough temp, but the oil contains condensation (water) which should be driven out by oil temps of 200-220F. I take a lot of care not to make short runs with my beloved Intek. Another reason to have an oil temp gauge . As a lowly homeowner it takes patience in fall or faced with only a few hauling tasks to get to operating temp, but I strongly suggest it.

I have a V6 Fiero , 1985, engine never apart. Have always run 10W-40 in it.

No, when tearing down an engine, when you find a burnt smelly, sticky goo pasted over everything that straight gas will barely even cut, it is
from broken down oil. Usually I find out that the user uses 10w40, many folks don't know. Many times the bottom bearing seizes, even when the engine is full of oil, sometimes the lower rod on a twin.
Whether or not the oils have changed or not in the last 10 years, I don't know, but I doubt it.

Of course synthetic is another topic altogether, but as far as the worst offenders of multi-viscosity breakdown is dino 10w40.

No is very strong. Let us define a little. Sludge , I guess can be seen as several things. So called varnish also. Overheated oil, ? 300-340F? will cause deposits ( perhaps a better term). Fish , I know you have seen many where I have not, but AC tractor engines are notorious for valve train failures also. Some of that is allegedly caused by deposits in the valve guides which cause the valve to seize momentarily and bends pushrods, causing them to drop out. I have personally seen sludge in auto (water cooled) engine valve covers where it was thick as mayo due to short runs and insufficient warming. Actually both sludge and varnish are really undefined and catch-all words like "pain." I am not surprised at seized and broken big ends sitting in what appears to be sufficient oil level....er, where were we? motoman

You must be a bit younger than I am. You are focusing more on the OHV age than I am I guess. With the onset of OHV engine's, they had to
undergo a decade or so of working the bugs out, and I don't blame 10w40 on their inherent problems much if at all. Luckily most folks us either
30 weight or 10w30, so this discussion doesn't come up much, but when it does, guys get kinda pissy about it, because Dad or Grandpa always
used 10w40 or something like that, usually with a certain brand in mind.

This site is kind of fun, I understand flack about my thoughts on 10w40, but the guys that want to argue the pushmower/flywheel point is
hilarious.

JDgreen said:

Has anyone noticed increased oil consumption in their push mowers while using 10W-30 rather than straight 30W? I am a stickler about using only 5W-30 in my auto engines but when it comes to small motors I really don't pay much attention to which one I use, between the two others. (10-30&30) The manuals caution not to use 10W-40 and I have never understood the reason why that weight would be any different from 10W-30, seems like it would better protect an engine in really hot weather.

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I dont get your manual, my manual in a 2013 unit, says use syn. 5w 30 for all year use,. they must be making the motors better now,.

Fish said:

You must be a bit younger than I am. You are focusing more on the OHV age than I am I guess. With the onset of OHV engine's, they had to
undergo a decade or so of working the bugs out, and I don't blame 10w40 on their inherent problems much if at all. Luckily most folks us either
30 weight or 10w30, so this discussion doesn't come up much, but when it does, guys get kinda pissy about it, because Dad or Grandpa always
used 10w40 or something like that, usually with a certain brand in mind.

This site is kind of fun, I understand flack about my thoughts on 10w40, but the guys that want to argue the pushmower/flywheel point is
hilarious.

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thank you but i am in the over 80 club,had to switch to a tractor, damn mower was to fast for my legs ,

JDgreen said:

Kenny, I have considered using synthetic oil but the cost scares me off, I generally change the oil in my push mowers just before I store them in the fall, and then again mid mowing season in late July, when I also resharpen the blades. Since I have to tip the push mowers on their side to remove the blade to sharpen it, it's not big deal to drain and change the oil at the same time. Since the mowers have no filter, it's easy to do the oil changes.

I know synthetics are made to prolong oil change intervals but I'm sticking with conventional oil for now.

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I went and read Valvoline site and they say sysnthetic oil is not designed to prolong intervals,

tybilly said:

I went and read Valvoline site and they say sysnthetic oil is not designed to prolong intervals,

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Have always been suspicious of that claim. The same amount of dirt and stuff gets in the oil....

tybilly said:

I went and read Valvoline site and they say sysnthetic oil is not designed to prolong intervals,

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I Did not recommend extended oil change interval ... I recommended using a good "Diesel" rated full synthetic engine oil... In all engines, gasoline and diesel... I do annual oil changes on all because No one engine ever gets that much use in any given year... I've been doing that for decades on many different engines. If you have any doubt as to how your engine oil is working, spend a few dollars and have a used oil analysis... that will tell you Exactly how your oil is working and if you are changing at the appropriate time. :smile:KennyV

I use Hd 40 in my push mowers, and it works out ok,

I have seen engines seize in the lower bearing, and the rods be in fine shape, have also seen the lower rod seize, and the one above it fine too, and the oil level is
fine. The smell is unforgettable, when it breaks down, and it is hard to cut with anything when trying to clean up the parts.

I use the Super Tech HD30 on the used pushmowers and riders I sell. Honda engines gets 10w-30 oil. I use amsoil sae30/10w-30 synthetic small engine oil on my personal riders. Switching to synthetic on my personal pushmowers this season.