30W Diesel Oil OK?

TomBrooklyn

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Is 30W diesel oil OK to use in lawnmowers and other 4 stroke small engines that call for 30W oil?
 

Rivets

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Short answer, yes. In our shop our bulk oil is diesel and unless requested that’s what we use when setting up all equipment or when charging oil.
 

hlw49

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Yes, diesel oil is different from gas engine oil. Auto engines are water cooled and run at a lower temperature than air cooled or diesel engines. They took most of the zinc out of auto oil years ago due to the fact catalytic converters don't like it and it stops them up. Zinc is a lubricant especially for the valve trane. Since the diesels run hotter because diesel engines fire from the heat of compression and don't use catalytic converters. Diesel oil works well in the small air cooled engine as well.
 

TomBrooklyn

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...Auto engines are water cooled and run at a lower temperature than air cooled or diesel engines. They took most of the zinc out of auto oil years ago due to the fact catalytic converters don't like it and it stops them up. Zinc is a lubricant especially for the valve trane....

Interesting. Could it be diesel oil is actually superior to auto oil for small air cooled engines? :)
 

TomBrooklyn

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...In our shop our bulk oil is diesel and unless requested that’s what we use when setting up all equipment or when charging oil.
What kind of shop and equipment is that? :)
 

Rivets

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Family run small engine repair shop, been around for 65+ years. Grandson and Granddaughter now have ownership. Original owner still comes in to check how things are going. Sell and repair 90% of todays engines. Product lines we carry include, but not limited to, Stihl, Echo, Toro, Simplicity, Kubota, plus Polaris.
 

bertsmobile1

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Interesting. Could it be diesel oil is actually superior to auto oil for small air cooled engines? :)
No
Mower oil is blended specifically for air cooled mowers that do not cause a very heavy particulate load into the oil and burn very lean
It has a superiour anti-oxidization and anti-corrosion additive package because for 99.9% of the time the engine is cold & not being used and like motorcycles run with a very small quantity of oil.

Diesel engines oils have a substantially different package designed to withstand extreme scuffing pressures , very high carbon build up and if it is truck oil continous operating as truck & trains are operating at least 50% of the time & some would approach 90%. And usually have massive oil tanks

Now the commercial realities come into play
Trucks have sumps that are measured in gallons and many of them would be changed monthly
Mowers have sump measured in ounces and at best get changed once a year if that
Thus the volume difference between the two is massive so diesel oil is usually 2/3 the price of mower oil and always supplied in bulk quantities
I used to deliver to a city council workshop and they used Rotella in 2 viscosities in everything, including 2 strokes & chain bars .
The reasoning , No one complains about smoke from the 2 strokes and they are used every day , engine oils are changed on operating hours to the second and it is hard work for employees to stuff a 44 gallon drum in their work bag .
 
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