prophet@umcp-cs.UUCP (Dennis Gibbs) (01/08/85)
<> In the January 1985 issue of Popular Science, there is an article about how to help cure/reduce pre-ignition and detonation. Within the article, there is a statement that General Motors (GM) will now void the warranty of any new GM car if the owner uses any oil with a 10W-40 viscosity rating, and has an oil- related engine problem. GM also recommends that GM cars out of warranty should not use any oil with a 10W-40 rating. They say that the additive in these oils has a tendancy to cause the piston rings to stick (I am recalling this explanation from memory, I may be wrong). As a matter of fact, one GM official in their Fuel and Lubricants group said that 10W-40 oil should "Never have seen the light of day". 10W-40 oil is the most popular selling viscosity range of oil, and in the past GM, along with most other car companies, have recommended it. Could it be that perhaps this is true? What about other makes of cars? Also, what about oils such as 20W-50? Should people with makes of cars other than GM avoid the use of 10W-40 oil? Or is this a compatibility problem that exists only with GM cars? Any info would be appreciated...Also, has any GM car owner received anything in the mail concerning this problem? Dennis -- Call-Me: Dennis Gibbs, Univ. of Md. Comp. Sci. Center. UUCP: {seismo,allegra,brl-bmd}!umcp-cs!prophet CSNet: prophet@umcp-cs BITNET: GIBBS@UMDB ARPA: prophet@Maryland