I have a 2000 coupe, automatic, LS1, 26,000 miles. The oil has been changed religiously every 3000 miles. I live in a cold climate(Buffalo)

The lifters make an awful racket when the engine is first started cold. If it sits for a couple of hours it is cold enough to make the same noise. I believe that the noise seems to be getting louder. I was originally concerned about piston slap .. but I think it is the lifters on the passengers side that make the most noise. The noise completely disappears after 5 minutes or so.

I left the car with the local dealer(Glen Campbell Chev) overnight. The dealer tells me that it is a carbon buildup on the upper engine and they want to do a clean out. I guess it involves adding two quarts of something to the engine running it for 20 minutes, letting it sit overnight, and running it again and draining it. Of course, Chevrolet considers this "routine maintenance" and I would be responsible for paying the $200. I told them that I considered routine maintenence to be anything I could do in the driveway and this procedure was not routine maintenance. The dealer who sold me the car 10 months ago (Corvette Palace in Austin, Texas - Great People) have never heard of this.

Anyone have any thoughts or ideas? The GM warrenty people and the Universal warrenty people(contract on car) do not want to replace the heads or whatever has to be done. That is what I think the problem is. Meanwhile, this has depreciated the valve of my vette considerably. I would have never bought it had I heard a racket like this when I was looking at the car.

Any thoughts .. ideas .. help ... thanks,
Dave

 

Good luck, it sounds like piston slap. GM knows and calls it "normal"

www.pistonslap.com

 

Great ....

You have to love it .. all this money for the great American sports car and you get an engine that sounds like it belongs in a garbage truck!

I still love the car lol

 

What type (brand) oil fillter are you using. It may be a poorly designed anti-siphon valve and it is allowing all the oil to drain back from the block, heads, lifter galley etc. when the engine is shut down. This means that on a cold start, (time since shut down, VS cold outside temperatures) the oil must be picked up by the pump, pressurized, and send through the galleys before it reaches the lifters. This results in lifter clatter for a few seconds, it also may be accompanied with a slight rod or bearing knock depending on the actual wear characteristics of any particular engine.
Fram has a poorly designed anti-siphon valve, as well as some other brands. Mobil, Wix, Champion, Amsoil, and AC all have better anti-siphon designs and materials.
Also, the better brands seems to flow better on cold starts, so that's another consideration.
Try changing the brand of filter, or if you are already using one of the better brands, change only the filter, top off the oil level to account for the filter change and try that for a few days. If your problem goes away, you solved the actual problem, not just the symptom.

 

I have the oil changed by the dealer ,, that is Mobil 1 . I dont know what filter they put in.
However, it is more than a few seconds .. it is 5 minutes until the engine is good and warm before the clatter goes away

 

I'm curious as to how you can destinguish lifter noise from pistonan slap??
FWIW unless you have changed springs/cam(which tend to be noisy)
very few people on this board has an issue with lifers. One of the few components in the valve train that is never/rarely replaced.

 

Try this, let the dealer know you'll pay the $200 for the service and if the noise is there after the de-carboning (lifter noise) tell them you want the $200 refund and fix the original lifter noise fixed under warantee.

 

I sometimes have the same issue with my car. When telling my technician about it, he gave me the exact same explanation, and the exact same potential fix. However, he didn't advise me to get it done. He basically said that it doesn't hurt anything, and the carbon will just eventually build up again.

 

Your dealer is probably right. Carbon buildup is a common issue with the LS1. It's not really a problem, but it's easily corrected. I believe the clean-out procedure is outlined in the Tech Tips section, if you can find it. By the way, it can be done in your garage or driveway.

 

I have it and mine also take more that a couple of minutes to go away. The car seems to run great. If it effects the running of the car, Ive never noticed it. But, we can agreed, we dont like the sound. I bet the LS2 and LS7 wont have it. Maybe they made a correction in those motors "since it's normal".

 

Thanks All -----> I appreciate the time you all took to give me advice. Love this board!!

I noticed yesterday that the clatter does not appear right away it takes several seconds to begin and will continue until warm.

thanks again

 

That is piston slap. Its fairly common on the LS1's. The cure is worse than the disease with the dealers involvement.

Carbon build up causes a knock under acceleration not the symptoms you are having.

I agree the noise sounds like a bad hydraulic lifter because of the tapping sound but I also agree that a bad lifter is very rare on the LS1.
Also a tapping lifter does not just go away after warmup.

 

I just don't know what to do .... about all I do know is that I dont like the noise and it definately takes value off the vette.

The vette runs strong. I dont notice any loss of power. Perhaps I will just sit on it for a while ..... maybe something will break and then the issue will be obvious ...

Damn ... you would think I was driving a Ford........

 

My car makes that noise, I accidentally drove through a lake (not literally) and sucked up a lot of water. As far as I can tell I bent a piston rod and its taps real loud, but that was well over 5k miles ago and shes still running strong. Im waiting for it to break and just replace the whole motor. Best of luck with that though.

 

Visit a website called....hmm....www.pistonslap.com I think it was. Do a search on here if that isn't it. I don't think it is a lifter either.