Gas motor oil in Cummins?

[d2500]

If a gasoline syn oil conforms to the API CF-4 standard as stated in the owners manual, can it be used in a diesel engine?



Also, the manual makes it seem that 10w30 is more versitile than 15w40 (temperature range wise), so why is not your first choice?



Thanks in advance!

 

[Pit Bull]

If an oil, synthetic or dino conforms to the API ratings in your owners manual it will work in your engine. I would not settle for any oil that was not rated CI-4 which is the latest classification. The recommended weight oil is 15w40. The 10w30 is for extreme cold conditions. If your truck is broken in and you live in a cold climate you could run Mobil synthetic Delvac 1 5w40 year round and change it along with a good filter (Stratapore Fleetguard) every 7500 miles. I use Rotella T 15w40 year round and change oil and filter every 5000 miles. I park my truck in a heated garage and if it is outside in extreme cold I plug it in. Since I don't work it does not sit out at work in the cold. You can do a search on oil and change intervals etc. and read till you go blind. Good luck.

 

[d2500]

Ok, I get it now...

The "C" in the API designation of CF-4 (as per the service manual) stands for "C"ommercial, or "diesel engine service"...



Duh! Just had to do my research

 

[nickleinonen]

Re: Ok, I get it now...

Originally posted by d2500

The "C" in the API designation of CF-4 (as per the service manual) stands for "C"ommercial, or "diesel engine service"...



Duh! Just had to do my research

on engine oil labels, the S in SJ SG SF etc signifys Spark ignition, the C in the oil label like CI CH CG CF signifys Compression ignition

 

[Pit Bull]

Re: Re: Ok, I get it now...

Originally posted by nickleinonen

on engine oil labels, the S in SJ SG SF etc signifies Spark ignition, the C in the oil label like CI CH CG CF signifies Compression ignition

Nick the S for Spark and the C for Compression is a neat way to remember that S is for gasoline and the C is for diesel but that is not what the S and C stand for. It was in a recent article in the TDR, can't remember if it was C for Commercial and S for Service or something like that.

 

[jwinnie]

I was always under the impression that the "C" stood for compression and the "S" stood for spark also. Goes to show you can't believe everything you hear.

This is straight off the API site: "Gasoline engine oil categories (for cars, vans, and light trucks with gasoline engines): Oils designed for gasoline-engine service fall under API’s “S” (Service) categories. Look for current service

categories SL and SJ. Diesel engine oil categories (for heavy-duty trucks and vehicles with diesel engines):

Oils designed for diesel-engine service fall under API’s “C” (Commercial)"

Here's the link: http://api-ep.api.org/filelibrary/ACF1E1.pdf

 

[RustyJC]

Originally posted by jwinnie

Oils designed for gasoline-engine service fall under API’s “S” (Service) categories.



Oils designed for diesel-engine service fall under API’s “C” (Commercial) categories.

Thus, "S" for spark and "C" for compression. That's the real world translation of the API boilerplate that's been used for years. By API's own description above, it's accurate if not official.



Rusty