ten minutes!

willscary · July 13, 2004

After hearing all the "piston slap" stories...I went for it. First a little background...I work for a construction company. All of our trucks are 2000 and newer 3/4 ton trucks with the 6.0L motor. They all sound the same. Sounds like loud lifter noise or ping under acceleration and sounds like a diesel at startup. According to all the sites on the net, this is "piston slap". These trucks have been doing this since they were broken in, and now all have between 80,000 and 175,000 miles on them. All of them work perfectly fine. They don't burn oil or get poor mileage, they just ping under acceleration. While this may be bad in theory, it has not hurt these trucks in any way.

So...my 2003 Silverado was bought used a month ago with 33,000 miles on it and the same engine noises. I took it to 2 dealers who both said it was normal and wrote me a service slip. I then called Chevy customer service. It took less than 10 minutes for the guy to offer me a 6 year/100,000 mile warranty on the motor. He says GM stands behind these motors and have performed tests on affected motors and found them to be reliable for over 300,000 miles.

I know that the company trucks have lasted with no problems, but the added warranty gives me piece of mind. While others want a new motor, I am quite happy with the warranty. If the motor doesn't blow up in the next 65,000 miles, it probably never will. Judging by the track record of our company trucks, there is little chance of that happening anyway.

It sure is nice to feel a little more secure!

One more thing...these first 2000 miles I have filled up 3 times with gas. I am averaging 17.2 mpg in my 2500 2wd regular cab with locker. I put a tonneau cover on it after filling up the last time, and now have 546 miles on this tank. I have 1/8 tank left per the guage. My guess is it will be about 18 mpg! The noise isn't hurting my mileage any!

Chev8.1 · July 14, 2004

Yeah, don't know why people are scared about Piston slap. Just motor telling you take'er easy until I am warmed up. Personally I think problem stems from abuse on a cold engine. This my third chevy with so-called piston slap, the last two went 120,000 plus miles on hard abuse from my right foot.

willscary · July 14, 2004

I have a Chevy prizm (Toyota Corolla clone) that began to cold start knock at about 45,000 miles. I put over 40,000 miles a year on it, and every morning it is quite loud. Fifteen seconds later it is silent. I get 43 MPG in the summer and 37 or so in the winter. It burns no oil. I have read that piston slap happens in many newer makes, not just GM. As long as I don't blow a hole in the block or start to burn fluids, I am ok with it.

snoman · July 14, 2004

I do not think they are scared as much as they feel ripped off as I would. I might expect piston slap in a 10 or 20 year old engine but not a new one in a 30 plus grand truck and before it is even worn out. It should not be there to begin with as it is caused by poor quaility control and sloppy production tolerances plain and simple. No it is not fatal but it is unpleasent to hear in a truck you are still paying for. I have a old jeep truck that has piston slap in it but it did not start until it was about 15 years old and it is 25 now. GM is dodging the bullet here because it would cost stock holder millions in profits and workers a chuck of their profit sharing check too to fix it so they are leting it slide. Even with a warranty when something is really wrong it is sometimes like pulling teeth to get GM to fix it. Give the 30 plus years they made the 350 and that it never had a piston slap problem from the factory and its proven reliabilty, its replacement is not setting the world on fire in consumer confidance.

chevroletmb · July 14, 2004

i work for a large gmc truck dealer and we've replaced more duramax engines than the 4.8, 5.3, 6.0l. yes some people don't like the noise

but i have not seen a single failure caused by it. not even oil consumption.

these engines don't leak like the 5.7 L used to . i can't think of a more reliable motor. so yes they may be noisy, but they will never break down because of it.

Chev8.1 · July 14, 2004

Most piston knock is due to type of piston(hypertonic) used and short skirt on the piston. Hypertonic piston are long lasting piston to help reduce scoring a piston. But they expand more than cast or forged pistons, therefore some excessive piston to bore clearance when cold. The short skirt is for reduce fiction and wear. short piston skirt also does not help the rocking of piston either. But are know to be brittle if adding bunch of horsepower.

willscary · July 14, 2004

Not adding anything. This truck is a work truck and will stay stock except for possibly changing to synthetic oil and a remote filter setup (for a larger filter and easier access). I haven't made up my mind yet.

willscary · July 14, 2004

By the way chevroletmb...thanks for the vote of confidence. As I have stated...I sold "ol' blue" with about 285,000 miles on her. Other than a broken wrist pin, a radiator, and a few starters, she was pretty much original. A '91 cheyenne 8600 gvw 2wd regular cab that I sold for $2500. I replaced her with this, and I sure hope the 2003 lasts as long as the '91 has!