Lifter noise on 2002 Coupe

[WolfeBros]

I am getting some lifter noise on my low mileage (4,400) coupe.
Noise appears about 30 seconds after a cold start and will sound until the engine reaches normal temperature. At that point it seems to diminish. If I shut the engine down and let it cool down just a bit....the noise comes back again. It sounds to me like just one lifter in the right bank. It is a fairly solid tapping noise that can be heard fairly easily inside the car. It also varies with engine rpm. Just had an oil change (Mobil 1 ) and was hoping that maybe this would help but it did not. Any ideas, suggestions? Is this common? Car is still under warranty. I just bought it two weeks ago so I don't know if it always made this noise. Thanks.

[froggy47]

Try a new oil filter (good one), maybe the anti drain feature on yours is bad.

Let the dealer adjust them , it is no big deal . Nothing in the engine is getting hurt . Mine chatters for 1 minute or so than gone , but I run mine about once a week so I expect it .
Thanks,
Joe

[theplayer]

I bought a 2002 coupe a month ago with the same problem. The orginal owner of the car told me he took it to the dealership and they told him the knock was normal. I did a little research and found that there was documentation on the knock problem and that there was nothing to worry about. So I bought the car. After having it for a while I decided to do more research on this "normal" knock. I found out that it can't be good whatever it is. It's called piston slap or cold start knock and it's a common problem on a lot of GM autos. I have coworkers who have GM trucks with 5.3 liters that have the same problem. It knocks when you start it and goes away after it warms up. Its not lifter knock. It is caused by incorrect tolerances in piston to bore ratios. If the tolerance is just a little off you will get the knock. That's why some engines do it and some don't. I took my car in and the dealership did pretty much nothing. First they told me that I didn't have moblie 1 syn in my car because it didn't look like syn oil and they changed the oil. The oil was darker than normal but that is a sign of piston trouble to me (blow by). I also have black deposites coming out of my tail pipes. After I told them I wasn't satisfied they called GM techline and GM told them that I had carbon build up or a piston tolerance problem. Frist of all the car has 8000 miles on it. If it did have carbon build up than that is a symptom of a problem not the problem. So they did a top engine clean with some chemical to eliminate the carbon. After that they told me to drive it for 300 miles and if it still knocks (which it still does after 150 miles) to bring it back. Service manager said that I might have piston slap and if I do then new pistons are in order. They hooked my car up to the computer and when they killed number 4 and 7 cylinder the knock stopped. That right there tells me that those are the two pistons that have incorrect tolerances in them. I am not going to let them rebuild my engine though. If that is the problem than I consider my engine a factory defect and I am going after a new engine under warranty. I would take your car in a see what they tell you about the knock. Check out this site too www.pistonslap.com I have read all kinds of stuff about people with the knock problem. Sometimes GM offers then an extended warranty and sometimes people get new engines and sometimes they get blown off. If I have a problem I won't settle for anything less than a new engine. They will do what you want if your not satisfied. I am going to an independent machanic tomorrow to get his opinion on my knock. I'll post what he tells me about it. Does any other corvette owners have this "knock" problem?

[theplayer]

Whats your take on this C4C5specialist?

[froggy47]

I almost bought a red z06 that had this & excessive oil use problem. It was a lemon law buyback. I decided to pass though, because the lemon title stayed w/ the car (even if fixed by dealer) and value would have gone down.

[Lucky7's81]

I'm ASE certified master technician and work at Gordon Chevrolet in Jacksonville FL. Let me start with the lifter noise after cold start. It is normal. There is nothing to be concerned about. Now, for excessive oil consumption there is a bulletin that addresses an o-ring that was probably cut when installed when built. There is also an updated engine calibration to address engine knock and fuel gauge going to empty while driving.

[froggy47]

ttt

[WEFs02]

My '02 Vette has had occasional lifter noise on cold startup since new. My '99 Sierra 5.3 developed piston slap at about 20k miles and it is a totally different noise. Injector "click" sounds close to lifter noise.

[Lucky7's81]

You are correct sr. Right now in the southeast region we are experiencing big problems with trailblazers valves sticking open. Last week we had 3 that turn over and have no compression in one or more cylinders and the head has to come off. One of the composit intake runners was melted shut comming off the motor. We don't have any major engine problems with vettes, silverados, tahoes. Lifter noise will not affect the longevity of the motor.

[theplayer]

I wish my noise was lifter noise but both the service manager and an outside master machenic said that it is not lifter noise. If the noise is there at start up and then disappears after warming up it's probaly not lifter noise. If it sounds like it is coming from the block than it's piston slap. Different engines have this problem in varying degrees. It could be a light sound to an annoying knock depending on how bad the tolerances are off with the knocking pistons. Sadly I had to learn all this the hard way. My first car purchase was a corvette with engine problems. The master mechanic I had look at my car told my to try to get a new engine under warranty. Now I am going to have to go through the service ladder to try to make that happen. Has anybody else had to deal with this issue of a knocking engine. Also how does a car fall under the lemon law?

[WolfeBros]

I can tell you that the engine knocks until it gets to normal temperature. 190 degrees or so. This is a few minutes of driving. I have never heard a lifter knock this long after starting. Usually a lifter type of noise will knock until the oil pressure gets up. I guess I better start complaining and get this thing documented. I will not settle for any BS. I want it fixed. This is now beginning to sound like a piston slap case. damn

[c4c5specialist]

HI there,
My TAKE on this is simply fact.
Fuel formulations today are at the worst they have been in 20 years.
Take that into account, and the 93 or better octane that is used on c5. This octane will produce more carbon deposits than lower octane fuels.
So, with the short skirt pistons, and the fact that the carbon interference, create the noise.
Now, the 02 to present date should not really be producing this condition, due to the updated teflon coated pistons.
If carbon buildup is the concern here, you can tell relatively quickly. Simply adding a bottle of 12345515 to the fuel system, and drive to 1/4 tank. If the noise is still there, your problem is NOT carbon tick. If the noise is diminished, or goes away, then you know that carbon buildup is the condition.
HOnestly, NO,, this has NEVER caused a reliability issue with Corvette.
As a sidebar, there may be other issues with the car mentioned here.
ACCURATE diagnosis is critical to finding the root cause.
Allthebest, c4c5

[theplayer]

WolfeBros:
It sounds like you and I have the same problem. Mine will knock from start up to operating temperature of 190. If it was lifter knock it would go away quicker. Both the service manager and a second opinion master mechanic told me it was piston slap or carbon buildup.
As far as the carbon buildup I now know that that is not my problem. They did two treatments to my engine and the car still knocks after 150 miles. The car knocked early on so I knew that carbon probably wasn’t the issue. The car only has 8300 miles on it now anyway.
I would definitely take your car in and get it looked at. Don’t let them BS you like they did me at first. If they tell you its normal like they did to the original owner of my car and others I know that have the same problem don’t believe them. I don’t care what they say it causes damage in some way. If it is normal than why doesn’t every car knock? They will probably want to do a carbon treatment first. If that doesn’t work than its piston slap and requires a rebuild to fix. They told me that I would need new pistons but I want a new long block. I don’t want to drive around a corvette with a rebuilt engine in it. I would take your car in and have it looked at for sure.

[Hib Halverson]

The noise described sounds like cold piston knock.

As c4c5specialist says, it is an annoyance not a reliablity/durability issue.