deisel oil vs. gas oil

[jkh]

Can anyone tell me the difference between deisel oil and gas oil? My brother-in-law has a chevy 6. 5 and in the owners manual it says 10-w-30 for temps below 32F but it doesn't specify deisel oil. I've always used deisel oil in deisel engines but I would like to know the technical difference. Thanks.

 

[baby.driver]

Diesel oil sticks to the rings better in high compression. Disperses soot better also.



Jay

 

[eGarwood]

Be carefull here. There are two ratings on any reputable oil, SAE and API if not DON'T use it. SAE stands for the Society of Automotive Engineers. They test oils and have minimal specs for for the numbers contained in these ratings; SAE 10W-30 stands for the weight ratings of the oil at given temperatures. 10W means that at the high extreme of the oils temperature rating it will act like a 10 weight oil (fairly thin able to flow easily) and 30 is the low extreme 30 weight a(little thicker). The numbers are useful when you change your oil, example: in the winter use a 10W-30 and in the summer use a 15W-40. This will help to maintain the proper balance between the oils flow characteristics and it's ability to stick to/lubricate parts, at different ambient temperatures. Equally important are the API ratings. API stands for the American Petroleum Institute. These ratings relate to the ignition characteristics of the related engine. 'S' for spark ignition(gasoline) and 'C' for compession ignition (diesel). I have two quarts of oil in front of me at the moment: one is specifically engineered for gasoline engines, the other for diesel. I am not going to name brands but they are both 100% synthetic. The gas oil is a 10w-30 with an API of SJ, CF. The first set of letters in the API are SJ you already know that the S designates it for Spark/Gas. The second letter 'J' is an indication of the date that particular standard was met. (the higher the letter in the alphabet the newer and better the standard. ) The same applies for the second API rating for this oil. CF, C for compression/diesel and F for the date of the standard. SOOO this oil can be used for both Gasoline and Diesel engines requiring a minimum API rating of SJ, CF respectively. The same goes for the deisel oil I have here. It's a 5w-30 with an API of CH-4, CF, CF-2, SJ. It is also O. K for use in gas and diesel applications. In closing you'll have to look in your buddies owners manual to see what API rating GM recommends for their engine. I hope this helps explain some of what you were wondering, and I hope I didn't confuse you more. After proof-reading what I wrote I am confused now and I pretty much understand it. :{ Ed3