diesel oil

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Mar 22, 2008 | 08:33 AM

92fordman

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diesel oil

is there any differece in diesel oil to gas motor oil i was wanting to run shell rotella in my truck its a 5.0 and its starting to use oil i was told that you couldnt use diesel oil in a gas motor because of the heat differece or somthing like that.

Mar 22, 2008 | 09:14 AM

YoGeorge

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From: Detroit

If it's rated for gas motors, it's fine...

Quote:

Originally Posted by 92fordman

I have a '91 BMW 318is with a 1.8 liter four, and the factory oil recommendation is for 15W-40. Because of its availability, the car has spent most of its life running Rotella (although I've been putting automotive 10W-40 into it in recent years for winter storage for a bit easier winter starting--10W-40 used to scare me more than it does now).

If the diesel oil is rated "SM" or "SL" or an otherwise gasoline motor rating, it'll be fine. I've recently learned that the diesel oil may have additional zinc (or other stuff) in it that is a help with flat tappet camshafts. Again, don't put in an oil that is *that* much heavier than the factory recommendation...

The differences in diesel to gas oil is that the diesel has other additives to help with soot, diesel fuel dilution, etc, but nothing in there to hurt a gasoline engine.

Mar 23, 2008 | 05:49 AM

jschira

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From: Mansfield, TX USA

Quote:

Originally Posted by YoGeorge

If the diesel oil is rated "SM" or "SL" or an otherwise gasoline motor rating, it'll be fine. I've recently learned that the diesel oil may have additional zinc (or other stuff) in it that is a help with flat tappet camshafts. Again, don't put in an oil that is *that* much heavier than the factory recommendation...

The differences in diesel to gas oil is that the diesel has other additives to help with soot, diesel fuel dilution, etc, but nothing in there to hurt a gasoline engine.

Zinc, in the form of ZDDP, is a very effective anti-wear/detergent agent that is also very cheap. ZDDP contains zinc and phosphates.

ZDDP can also foul cat. converters, so it has slowly been eliminated in gasser oils. Diesels, until recently, did not have cats, so ZDDP was an acceptable additive.

As diesels now have cats, ZDDP has all but been eliminated from diesel oils too.

And you are correct, diesel oils have higher detergent and soot control additives than gasser oils. This is why diesel oils are a little more expensive.

BTW - The high ZDDP, and other additive loads in older diesel oils (rated CF-4 or CG-4), make then excellent oils for antique cars.

Mar 24, 2008 | 01:28 PM

jimandmandy

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From: Running Springs CA

Chevron Delo 400 LE (CJ-4) still has 1200ppm zinc. So, yes it has been reduced, but still a lot more than "energy conserving" grades of gasser motor oils.

Since your profile lists Florida, 15W-40 wont hurt a thing. I ran 15W-40 Delo in a 5.0 down to +20F (rated for +4F) without any starting issues.

Jim

Apr 4, 2008 | 12:36 AM

69-highboy

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These classifications are arranged into two different groups, one for automotive gasoline engine service and the other for commercial diesel engine service. The former is listed in "S" or "Service" categories (presently SA through SM) and the later is listed in "C" or "Commercial" categories (presently CA through CI-4 PLUS).

Typically the automotive category will only show the “S” service category in the donut (see Figure 1) while the “C” category will have the C category followed by the S service category. Hence a donut for a diesel engine oil meeting both API CI-4 Plus (diesel) and API SM (gasoline) is shown in Figure 3.

They way I learned it "S" stood for spark ignition, and "C" stood for compression ignition.