Cold start engine rap - does anything help?
Tech Contributor
Joined: May 2008
Posts: 3,100
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From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Heel & Toe
Joined: Oct 2008
Posts: 22
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From: roopville georgia
new engine design
Just bought a 2004 C5 coupe with auto and 15K miles. It has a very noticeable rapping when cold. I probably shouldn't have bought the car, but I test drove it when warm and there was no rapping. The engine really has to warm up before the rapping goes away. I'm disappointed the seller never mentioned this.
I'm assuming it's a piston which is a loose fit to its' bore, and I know there are issues about GM piston fitment. I also realize that alum pistons expand/contract at different rates than steel blocks. I've owned plenty of other Chevy cars which made the cold engine noise, but this one seems kinda bad.
Are you guys using any special oils or additives which reduces this rapping?
thanks
I'm assuming it's a piston which is a loose fit to its' bore, and I know there are issues about GM piston fitment. I also realize that alum pistons expand/contract at different rates than steel blocks. I've owned plenty of other Chevy cars which made the cold engine noise, but this one seems kinda bad.
Are you guys using any special oils or additives which reduces this rapping?
thanks
Racer
Joined: Nov 2008
Posts: 378
Likes: 0
the 1997 up corvette engine was a all new engine designed for long life under hard driving ! there are plenty of litature on the LSI engine . the entire engine is the best ever built by general motors ! the pistons have floating wrist pin for long life at hard driving ! the floating wrist pins are the source of the noise everyone hears while the engine is cold . if they continue to rattle when warm you have problems with most any moving parts ? back in the 60's Jahns pistons was one of the 1st to sell these floating wrist pin pistons an they were super high dollar as they were mostly high compression up to 13.5 compression an were indestructive or worth thier money ! these pistons needed to be warm to be quiet as they were clearanced to make more H.P. with less friction. if you let the vette engine warm up the noise will go away . the LSI is the best engine ever built in my opinion . use good oil an warm the engine to normal temp. an hold the pedal to the metal ! it's made to take the R.P.M. duane # 122540 born 3/6/00 SSR # 6363 born 3/02/04 just my humble opinion !!
My 2002 had it. My 1999 does not.
