piston slap

cbz2500hd · November 28, 2003

I own a 2003 2500hd with 6.0 vortec. My motor knocks cold or hot. I took it to one dealer to get what i thought was a very loose lifter adjusted. They called me back to let me know it was piston slap and that gm says it not detrimental to my motor. People have actually asked me if it has a duramax in it . GM offered me a 100,000 mile 6 year warranty which I refused. I'm afraid to drive this truck on a long trip. Does anyone else have this problem .. My truck has only 8500 miles. I'll bet it doesn't last 30,000. Does anyone know of a fix.

k1500chevy97 · November 28, 2003

good fix . . . trade it in .

it wont stop or get better it will only get worse

gunslinger45 · November 28, 2003

The infamous piston slap issue eh? Well, first of all, I assume you have checked out the bazillion posts on this issue on this website and others and are familiar with the various opinions and experiences out there. These are two questions I would have before making a decision on your path forward.

1) Is the engine using excessive oil right now? If yes, (maybe 1qt/2000 miles) then it would tell me that the piston slap is excessive and is causing damage to the engine. If not, its still an issue, but bodes better for longer engine life.

2) Do you notice the knocking only at idle when cold and warmed up, or is it across a wider RPM band? If only at idle, then the problem is not quite as bad. If it does it across a wider band, than that is very very bad and would necessitate getting a new engine either through a new truck or warranty.

Now I know the bottom line is that this piston slap issue sucks. I have a 2003 8.1L that exhibits the cold start knock that goes away after warming up and I not happy that I cranked out serious dough for a push rod V-8 that sounds worse at idle than a V-8 made about 30 years ago. That being said however, the track record for the modern GM engines, even the 2001-02 engines that did not have the "fix" is still quite good and I have yet to see any documented evidence of reduced engine life from the issue. Yes, conceptually, one would think the problem would cause decreased engine life, but except for a few isolated cases, there is not much out there. However, I have not heard your engine and I don't know how bad it is, so your situation could be different. My opinion on your path forward:

1) Make a lot of freakin noise to GM. Go to the dealer alot, call GMs customer lines, WRITE the company and tell them what's going on. And make sure you do all this in a mature manner. Be assertive, but not an *hole. If the dealer gets tired or gives you attitude, stand your ground and insist you will be back until the issue is resolved and let them know that you are talking to GM corporate about the issue. From what I have seen, if your issue is really as bad as you say, the absolute minimum you should be able to get is a new engine under warranty.

2) Not sure I would have refused the warranty upgrade, assuming it was for free. You basically get some good insurance should the problem increase and actually cause some kind of failure, and you still don't lose your option of #1 above to make noise and still eventually have the engine replaced.

3) I think trading in without having the support of the dealership would be the worst financial decision for you, but obviously be the quickest solution. Some individuals who have made enough noise that were in your same situation got GM to buy the truck back which is better, but you will still lose some money for mileage. However, if you going to have this truck for a while and you can't get passed the issue, than that's something that's hard to put a dollar value on.

Bottom line, make lots of noise, talk to GM in a professional educated manner and get a new engine put in that thing at their expense. Easier said than done, maybe, but its not that uncommon if you're persistent. Best of luck, and I understand how frustrated you probably are.

Gunslinger

cbz2500hd · November 29, 2003

My piston slap occurs during startup but doesn't go away.It is most noticablefrom

1000 to 1500 rpm. I can drive it at that rpm and it sounds like a duramax for miles.

I can here it at higher rpms but it is more faint. I drive half an hour to work in morning at about 70mph and the minute I get back in to range 1000 to 1500 I'm back in the duramax. It's gotten alot worse in the last two months. I don't want to wait til it blows up. And is the new motor going to knock too? Now the lady from GM won't even return my calls. Does not use oil yet.

gunslinger45 · November 29, 2003

Well, the fact that it is evident at other RPMs than idle and you say it has gotten worse says that the problem is unacceptable in my opinion. Most of the CSK issues out there are only evident at idle and go away after warming up, so I think you have an extreme case. Have you asked to speak to the dealership owner? I just can't believe that if the sound is that evident at 1500 rpm a service guy who I hope has gone on a ride with you would not think something was very wrong. As for if the new motor will be as bad, I would put odds against it. The GM V-8s are noisy at cold startup, but in general, most of the noise goes away from most of the engines after 5 minutes or so. You may just be the recipient of a bad apple. Besides, if the new engine is just as bad, but you got it replaced with the warranty, then all you are charged is your time and convienience (non-trivial at I times). So I would keep pushing for the new motor, or of course if you can swing a good deal on a trade in, and it will make you happy in the end, then go for it. But if you stick with GM, than you get no more guarantees that you'll get a better motor than if you just have it changed out under warranty. So I still think that's your best bet. Its sucks you have go through such an uphill battle just to get what you paid for. Keep us updated.

Gunslinger

raventai · November 29, 2003

cold start knock/piston slap is very common in the GM vortec series, My 8.1 has it also, I started at 250 miles and has made it 50k no loss of performance or any problems (not any related to CSK anyway)

still having the knock after warm up is uncommon but not unheard off, I would think that you have a particularly bad case of it

although it may not cause any real problems it really pisses me off and I wish I had lemon lawed my '01 when I could have, mainly because the truck has lost a lot of resale value, GM got a lot of money out of my and gave my a nasty sounding motor and refused to fix or extend my watrrenty

“no really I swear that is not a rod knock, that is the normal condition ”

I know it is ok but try convincing someone else to buy it

HDROCK · December 1, 2003

I hate to hear it bud..... My truck has it I took the warranty and figured that I will just wait and see what it does. Probably want to atleast take the warranty if you cant get them to do anything else, cause it will make it worth more at trade in. I would encourage you to look at the website www.#####.com I really was hoping that GM's promise that it would be fixed in 2003 was true guess not

This really makes me mad that we have new trucks that make these noises

HDROCK · December 1, 2003

I just posted but the website got like blocked out; not sure what happened the website is pistonslap dot com.. Check it out there is a story from the Detroit Free Press about this problem and the class action law suit against GM

jezushadlonghair · December 14, 2003

CBZ, I just came across this topic and I was wondering what you said to the dealer to have them offer an extended warranty? My father's HD has the same problem and an extended warranty would put him a little at ease. Thanks.

cbz2500hd · December 14, 2003

I took it to a dealer because I thought I had a loose lifter and they(the dealer) diagnosed it with . They told me it is normal and that it would not hurt the motor but if that was not good enough they gave me a gmc truck customer assistance #.

I called the number and then they (gmc) verified the problem with the dealer and then they asked me if I wished to accept a 100,000 mile - 6 year warranty. They say it's not anything to worry about yet the name of the warranty is called "injured component warranty". Thats fine and all if all you expect out of your truck is 100,000 miles. What about resale value? I'm taking it back to the dealer tues. If they tell me it's normal I'm getting a lawyer.

422 SS · December 15, 2003

You don't have to settle for the "it's normal crap".Keep all documentation and contact an attorney.I successfully sued GM over my 500 mile to the quart oil burning 8.1.It took a year but was worth it.I don't know where you live but Ohio has the best lemon-law in the country according to my attorney.If GM told you their not going to do anything more for you they won't.Once I was told at the dealer it was normal for my new truck to burn that much oil they became irrelevant and I decided to seek my own recourse.Contact a lemon-law specific attorney and see what happens.

HDROCK · December 15, 2003

I have a 6.0 with 35,000 miles, I took the warranty because I figured it was better than nothing. It really sucks that our new trucks have these noises, I guess GM knows that its much cheaper to let some customers take them to court then to replace everyones engine.

Here is my question my dads 2000 5.3 Suburban had it, my 2001 2500HD 6.0 has it and Iam hearing about people with 2003 models who have it. This has been a problem now for 3 years and they havent done anything about it.

WHY HASNT GM FIXED IT

December 17, 2003

HDROCK, Needle Rat here! Trying this forum for the warm start knock I'm having. Posted about it under engines. MCT is the only place to date I've had any decent responses from.

Regards,

Jeff

swl2126 · December 22, 2003

Gunslinger,

You mentioned the 2003 "fix". Do you know what that is?

December 25, 2003

In regards to this being normal no way. When GM puts out a press release that the issue was resolved in late '02 and all 03 and newer yet turn around and say it's normal is absolute BS. I included this in a letter to GM I sent last week. I stated I purchased the 03 as they stated the issue was resolved. My problem is a warm start knock which they have no idea about. My dealer told me last week that they just received a memo about the slap and that they are to replace all pistons with the new design they now have and not to replace only the offending ones. He did not remember which engines/years it applied to but is going to check it out and get back to me. What I wonder is if it is normal and does not cause any problems, they why are they working on a "fix". Wouldn't a "fix" mean something is not normal/not correct/broken? Mine has already had the rear end re-done, front & rear brakes & rotors replaced, I just noticed my heated mirror no longer heats (passenger side), the OnStar mic had to be replaced, the PCV was making an obnoxious whistle and was replaced. I only have ~ 2500 miles at this time. Built on Monday or Friday? I'm thinking more like Saturday by the cleaning crew!

Jeff