prophet@umcp-cs.UUCP (Dennis Gibbs) (01/08/85)
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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
--
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