Hey Guys,

Found some interesting reading outside these boards. What is the viability of GM 4718 and CH-4 approved oils on Gasoline engines? Yes, meeting API SL specs is very easy and it is not really a good way of judging oil.

Just curious because there is very few oils that I see that actually mention these test approvals.

Regards,

Oz

CH-4 is a diesel spec--not really pertinent to use in gas engines.

The GM 4718 spec, best I recall, came out when GM started putting Mobil 1 into Corvettes--and, best I know, requires a synthetic to meet it.

Yes, I know CH-4 is primarily used in the Diesel group. However, since most Diesel oils that I've seen are Sx licensed (Mobil Delvac 1, AMSOIL 3000, Shell Rotella, Petro Canada Duron, etc.), I'd figure the Cx standards are far more rigorous since most Sx oils are only rated up to CF in the commercial ratings dept. And CH-4 rated oils typically have SJ or SH ratings. This is what I need confirmation on...I guess

Regards,

Oz

European ACEA A-3 standard seems to be slightly better than SL.
The A3 spec I like is the HTHS >3.5.
The jury is still out on the necessity of this parameter,
but it indicates better hydrodynamic lubrication at high temp.
Xw30 oils have trouble meeting A3 Xw40 oils only meet it if they are 0w40 or 5w40 (fuel economy part of A3).

see link
http://www.bobistheoilguy.com/states%20of%20lubrication.html

If hydrodynamic lube is overcome then barrier or boundary layer lube is used.
For that I would look for an oil with good levels of ZDDP and Moly.
Mobil 1 is using less ZDDP but promises good protection with Super Syn

You probably know that, but that is what I've been searching for in wear protection.

[ August 01, 2002, 12:30 PM: Message edited by: jjbula ]

Do you know how GM 4718 might be superior to SL?