After reading through quite a few threads on oil changes, UOA's & VOA's, it appears that there are a few owners of C5 'vettes complaining of piston slap. My friend has a 2002 GMC pick-up with the small V8 and his truck also has noticeable piston slap. The service manager at the local GMC dealer said GM's been using pistons that have a reduced or a shorter skirt. Now, my question is what's the reason for using these pistons? And, will using a heavier weight synthetic, like M1 15W-50, make any difference?
Piston slap
- Thread starter zeke
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My experience with slap happy pistons is that a higher viscosity oil does quiet them.
Dan, this begs the question: Do engineers @ GM think that piston slap is favorable to a little less gas mileage? Perhaps this design inspiration didn't come from the engineers - I suppose it was probably the bean-counters
One other thing: If the higher viscosity will improve the piston slap, what about that age-old problem of wear in the cam lobes? Didn't GM warn about this with 10W-40 use?
Let's not forget that many LS1 F-Body owners with heavy slappers disassembled their motors only to find wrongly matched pistons to the particular clearences in a few of the cylinders
As long as the slap quiets to nearly silent after the engine warms, there should be little to no decrease in engine longevity. I know a few people with 3.1/3.4L GM engines with over 150K that still run great, other than piston slap and intake gasket replacment every 50K
My 1997 Lumina 3.1 has 85,000 miles on it. Piston slap for sure and it quiets down after a minute. However, I have never replaced the intake gasket.quote:
Originally posted by Drew99GT:
I know a few people with 3.1/3.4L GM engines with over 150K that still run great, other than piston slap and intake gasket replacment every 50K
Define piston slap, to quote an ex-pres. I know that piston slap on a cold start is a pretty common complaint on LT1 Chevy V8's in Corvettes, Camaros, and Impala SS's in the mid 90's. It goes away as soon as the oil begins to circulate.
The solution I suggested was a pre oiler. This is a device that you turn on prior to hitting the starter to build up oil pressure in the engine. Remember the old oil commercial that went something like, 'Starting your car is the WORST thing you can do to an engine.' What it was saying was true, the first few seconds after starting an engine is the hardest,because there is no oil protecting the metal surfaces. Look for pre oil or pre lube on your Search engine. and see what I am talking about. Actually the pre oiler comes on automatically when you turn the ignition on.
The solution I suggested was a pre oiler. This is a device that you turn on prior to hitting the starter to build up oil pressure in the engine. Remember the old oil commercial that went something like, 'Starting your car is the WORST thing you can do to an engine.' What it was saying was true, the first few seconds after starting an engine is the hardest,because there is no oil protecting the metal surfaces. Look for pre oil or pre lube on your Search engine. and see what I am talking about. Actually the pre oiler comes on automatically when you turn the ignition on.
WEll, I would be very upset if my $40,000 dollar car slapped like it had 300,000 miles on it when new!!
I don't think a pre oiler will solve piston slap as this continues (the noise) until the metal expands and the slap stops which is usually several minutes. A pre oiler would be useless for this.
What solved my piston slap was the use of Schaeffers #132 and LC, 8 ounces of the mixture seems to have cured it.
What solved my piston slap was the use of Schaeffers #132 and LC, 8 ounces of the mixture seems to have cured it.
Chrysler had this problem in the early 1990s in 4.0 Jeeps and they replaced the engine if the slap was bad enough. Wife has a 1999 with 55,000 miles and no slap, so they must have worked out the problem. Toyota also had a piston slap issue at about the same time. My advise is not to worry about it unless the slap doesn't go away after a few minutes.
You are lucky!quote:
Originally posted by CJH:
My 1997 Lumina 3.1 has 85,000 miles on it. Piston slap for sure and it quiets down after a minute. However, I have never replaced the intake gasket.quote:
Originally posted by Drew99GT:
I know a few people with 3.1/3.4L GM engines with over 150K that still run great, other than piston slap and intake gasket replacment every 50K
How many years with the Dexcool?
2 years. The problem is that dexcool is rumored to have problems with holding up-but it does not attack the gaskets. Supposedly thats why GM came out with it.
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