GM ENGINE KNOCK

rayt2

No I have'nt heard of a knocking engine failure (yet) either nor do I want to be the first. The point still being GM is decieving the customer. Look back at the track record of the 3.1 engine knock on http://www.gmpistonslap.cjb.net website, they did have problems. Unless you trade the truck in how ya going to explain for a private sale that the knock is normal to a potential buyer? I would'nt be the one to buy a truck w/a noisy engine, common sense would dictate.

Thru letters to states attorney generals and the media we as a whole can haul GM's [non-permissible content removed] to the carpet so they have to address and correct the issue. Look how long it took for the exploding gas tank issue to get settled, but it did get settled thru media and the states pressure on GM.

Ray T.

ryanbab

i just listened to the sample knock on the site. DAMN that was loud. Mine is nowhere close to that. That doesnt sound good at all.

everhart

That's the problem some people have a very light tap & others have a full blown BANG. I'm just glad mine doesn't have either. A friend of mine has 15- 2500HD & LD trucks 2000, 2001, 2002's all 6.0's some are quiet as a church mouse & a few are very noisy. He does have a 2000HD 6.0 with 89,000 miles on it with cold start knock & pings under heavy acceleration, he told the dealer he was going to drive it till it breaks but so far it hasn't.

nomoregm

... As I understand it, catastrophic engine failure is not necessarily the main concern (unless you're Dale Earnhardt [Jr.]). Rather, performance and longevity is the worry with knocking engines. Such things as horsepower/compression loss, abnormal oil consumption, abnormally high (and in some states illegal) emissions, fouled plugs, carbon build-up, etc.--again, I'm not a tech but you don't need to be a rocket scientist to know that engine parts banging together audibly and blow-by is not desired and more than mere "annoyance" (GM). Also you don't have to be a Harvard lawyer to see that GM's claim of knocking engines being normal is indeed baseless.

As a Subaru representative stated (with bias) when they had their piston slap problem on the 2.5 liter, "You might only get 175K out of it instead of 200K miles" (from www.LS1.com's petition--go to the Subaru link). I would reply, you might get 75K instead of 200k and the truth is perhaps somewhere in the middle. The point is we shouldn't have to HEAR our engines grinding themselves down to a premature death, with a reduction in performance, etc., etc.

I think a better question might be, how many knockers have tested low in compression and horsepower (on a dyno) and higher on emissions than the non-knockers. Those specs are easily verifiable and perhaps our best evidence of at least, false advertising by GM (remember the Ford Mustang Cobra debacle?). At some point I will have mine tested. I'll let you know. If anyone else has already--tell me more. Thanks to all.

tomh12

Excellent post. I agree that reduced performance, increased emissions, high oil consumption, fouled plugs, and compression loss would be an unacceptable condition(I call that "failure")....BUT, at what point does this get blamed on the piston slap/knock, as opposed to "normal" wear. And, how would you ever prove the engines to be compared have been exposed to the same maintenance and use conditions? Sample size for testing would have to be very large to rule out individual variations. I guess there must be engines that are a lot worse than mine and if I had one maybe I'd feel differently. As is, I still consider this the best truck/drive- train I have owned.
Tom

teadie1

HEY ryanbab, PLEASE POST ADDRESS OF SIT EWHERE U CAN LISTEN TO PISTON SLAP NOISE. teadie1

nomoregm

TEADIE1: Listen here: http://emer.homedns.org/ls1knocksound/knock.wma

TOM: My 01, 350 Camaro has only 7K miles. IMHO, I shouldn't have any dramatic decrease in HP/compression or increase in emissions compared to a new engine. From all I've read, it should be at its peak performance having broke in completely. Most knockers are in the same range and many are much less. The only standard I'm aware of as far as engine longevity is, "If it knocks, it either needs oil or rebuilding". But I agree your point is arguable and perhaps GM's position is, sue us and let a judge decide. Which is why all of us are losing sleep here and will likely never by another GM--the trust is not there.

I think, if you can isolate the knock to one or two pistons (in my case, #8 only) and those pistons are showing an appreciable loss in compression, it would be difficult for GM to deny in any tribunal. Difficulty is getting them to court. Our job is to get them into the court of "public opinion" and let others know just how worthless a GM 3/36 warranty is. All of the other makes which I'm aware of, Jeep, Ford(with some prodding), and even the Japanese (Subaru), took care of customers (replaced engines) with their similar piston slap issues.

Have you noticed that GM won't compression test any of the customers with complaints? They don't drive the car or stethoscope it. They stand next to it and go, "Oh yah, GM says that's normal"--("Go away--the Wizard sees no one!"). I think I'll request it nest time I talk to customer service. If they say no, I'll want that in writing.

There's nothing wrong with liking your vehicle, that's America. But I find myself rubber-necking all the Japanese vehicles as I drive by their dealers lately....

The petition is growing. Sign up here: http://emer.homedns.org/ls1_knock/index.asp

losangelesemt

Well I admire the fact that you seem to be one of the few GM owners that will actually acknowledge this is a problem and not make a million excuses why its not. I personally think GMs lemon trees are ripening and abundant in yield. For everyone thats gonna bring in "mine doesn't do it" .. " its the best truck I've ever had" .. well thats fine and best of luck to you guys and your trucks. To the many others with GM knock/slap/rattles etc. who don't find this acceptable, good for you and good luck with any future claims.

Nomoregm .. I think your name sums it up as best as I ever could

tomh12

If you have gone so far as to isolate the knocking piston in your 350, why have you not done a compression test and emissions test? Or have you? If so, what did it show? (If you have previously posted this, I apologize for missing it.)
I will admit that the "knock" may affect the resale value whether there is any actual damage or not. Therefore, I wish you good luck.
Tom

mrb11

Has anyone experienced the knock disappearing in their 7.4L?
Knock started at about 5K miles on my new 1998. At about 30K miles it disappeared and has not returned since. I now have 34K miles on the truck. I did nothing different to the truck. I burn the same gas, and use the same oil and filter as always. The dealer never touched the engine.
I've no cold or warm start knock. Can a knock heal itself? Any explanations?

selkirk

I have a 2000 Silverado 2500, 6.0L engine with about 34,000 miles on it. I haven't had the cold start knock, but have an intermittent rattle on moderate acceleration when fully warmed up. It sounds like rolling small rocks around in a can. This started about 5000 miles ago. At first I thought it was ping, but I don't get it on heavy acceleration and have heard it a few times while decelerating (i.e. descending a grade). Anybody have some thoughts on this?

bigorangefan

It has been a while since I have posted on these boards, hope everyone and their family's are well.
Iam in the market for a 2500hd crew cab 4x4 duramax either GMC or Chevy. What is the going price over invoice? I live in So Ca but do not mind going out of state for a good deal. It seems to me about a year ago there was a post about a GMC dealer in Oklahoma who was selling for a few hundred over invoice. Any help would be very much appreciated.

Thanks/Chris

nomoregm

Dear Big, do yourself a big favor. Buy a Tundra. Same money, thrice the reliability and a warranty with teeth. Have you read any of the posts here? If you like diesels, buy a GM gas model--they sound the same. Seriously, I think you'll agree that none of us here can recommend a GM product to a family man such as yourself. Bring a copy of this web page, http://www.angelfire.com/tx5/gmpistonslap/index.html, and this one, http://emer.homedns.org/ls1_knock/index.asp to your GM dealer and tell them we sent you. Then walk away with your hard-earned money and go straight to your nearest Japanese truck dealer. And thank God that "someone saved your life tonight". If you must buy American, get a Ford. Thanks--and you're welcome.

nomoregm

If I had the time and/or resources, I would do the tests myself but you'll agree that GM would love to find that I had an independent tinker with my car's "warranted" engine. It's not my job.

Pursuant to my BBB complaint, I'm waiting for a GM-promised call from a regional service rep. which is several days overdue. I'll request those tests from him. You'll be the first to know.

Frankly, I wasn't worried about resale that much until this problem surfaced. I wanted to keep and maintain the car so I could someday give it to one of my kids. Now I feel like I just want out. But I'm not going to let GM do this to us. American products don't hold their value (compared to foreign makes) under any circumstances. This is just one of the larger reasons why....

I'll remind you, at least three other car makes with piston slap issues replaced those engines for customers who persisted. I've done the research. GM has taken the position that they will do nothing until it starts hurting thier bottom line--believe it. Knocking motors is a defect. Both your grandma and your baby sister will tell you that.

joe3891

has a sludge problem and may fix your engine or may not,if not your out $5000.

seelig

why else do you think we bought Chevy instead of Toyota?.......besides the fact that Toyota doesn't make a fullsized truck.

xyz71

I got "the" letter Saturday - extending the engine warranty to 6 years or 100,000 miles. Even though my engine does not knock, it was worth a 5 minute phone call. This is more than fair in my situation - now if I had a loud knock that lasted 1/2 a minute or more I would want it fixed - screw the x coverage.

jaguar0027

upon cold startup... How did you guys get yours? I assume the dealer had to 'document' it first which should not be a problem.

Did you call GM customer assistance for the ext warranty or some other number???

Thanks

bigblackmotor

We originally had some Netscape compatibility problems and have tweaked the site significantly in the last week. We now have a .wav file where you can listen to the slap if you so desire. If you have the dreaded GM PISTON SLAP, Come join us! http://www.gmpistonslap.cjb.net

nomoregm

Keep up the good work. Regarding the previous posts, I wish my knock lasted only 15 seconds. I might also have taken the extended warranty. I knock for 15-20 minutes and still hear it hot. As far as the Toyota sludge problem, all makers deny claims, initially--warranties are not giveaways. But you failed to mention that Toyota is making good on those engines apparently after some aggressive press coverage, Automotive News, Etc. Go to:

 http://www.9wusa.com/consumer/consumer_article.asp?storyid=4725

Perhaps the American press is more aggressive with the foreign makes--especially at war time.

But we Americans still wait for our great American car company to do the right thing. Further, this is a GM Knock Site. Stay focused. All makes have problems (some more than others) and relative internet forums. Any mention of other car maker's problems here should be specific to how the company ultimately reacted regarding the warranty. Do the research before you speak. Perhaps Toyota wanted to maintain their number 1 status. GM, however, is content to sell to a large number of apple-pie loving lemmings like me who continue to buy substandard products. GM's warranty is corporate silly-putty that's controlled by lawyers and accountants on behalf of shareholders. Integrity it seems, is selling at too high a price for GM's Executive Board. GM's reliability ratings are consistently lackluster. Yet we continue to buy. They rub that American flag in your face and tug like vultures at our patriotic purse strings. They should be ashamed.

We won't be fooled again.

seelig

thanks for posting the link........it's about time someone came in here with some great info such as you have.

thx

roger350

Seems like a while back someone was talking about a particular brand of fuel system cleaner they were using with some success, instead of doing the GM top end soak treatment? It wasn't one of the gas station brands, but ceveral people swore by the brand, and said after a few treatments, there knock went away, or was less pronounced? Does anyone remember what that stuff was, and where you can get it? Thanks.

rayt2

The product was BG, alot of the dealers recommend using it for fuel system maintenance (some will use it against you if you haven't used it reguarly). You'll have to scroll back for the website that was posted previously, I don't know it off hand.

Ray T.

4x4man

As Ray mentioned it is BG 44K. I had great sucess with this product. I can get it at Napa Auto Parts, and have seen it available at some dealers. However like other things at the dealer, I would expect it to cost more from them... At Napa I can pick up a can of 44K for $19. I can go about 2000 miles knock free per can (remember I have the carbon knock, not piston slap). Kinda crazy how there are different types of knocks on these Vortecs....nothing like getting added "features" for free, huh??

The website to BG products is: http://www.bgprod.com/autofuel.html

Bob

obyone

Marvel Mystery oil. Also that Techroline stuff from Chevron.

joe3891

So what is a Tundra?

obyone

is called full sized by Toyota. Doing a comparison, the Dakota compares closer to the Tundra than a Tundra to a full sized 1/2 ton. well its Toyota's second attempt. Hopefully they will get it right the third time.

nlt

I just spent the last 2 days reading on the post.
I personally love my truck. I have a slight tick notice in the engine. I have a 2001 5.3. So I will be calling GM. I also have a 2000 TA with the LS1 5.7 IT purrrrrs.
I love my Truck. It has 14,000. I'm so frustrated for all of with the load knocking. I'll do my part to help you all.
I would have bought a Tundra but I'm not 5 ft tall.
I had a Ford. Traded it in for a GMC.
And if you own a Dodge. Well what can be said about you!
My point is that all you who are posting who do not own GM truck. Get out of here!

tep

Thanks for the support with the http://www.gmpistonslap.cjb.net website guys. For some of you who have not taken the time to look at all the info available on the site, my 8.1 Liter is using oil at the max 1Qt for 2K miles (except for the fact it is a vehicle over 8500 GVWR which has no "NORMAL" maximum oil consumption standards). A recent borescope inspection found deep vertical scratches in the cylinder bore of #8. I ran a compression test and found #8 to be 10 PSI lower than any other cylinder. Someone above touched on compression testing which is so easy to do. If you couple that with a borescope inpection (which isn't typically as easy to get done) you have the hardest most solid evidence for driving it home on GM. Demand compression testing and borescope analysis at your dealer. They may find ways to deny doing it but, we are hanging GM's fraudulent butts out to dry. We will find a way to drive it home on GM Senior Mnagement!!!! Come by and participate in the fun!!

nwjetboat

Sorry for the late post, but the replacement date for my 7.4 was 4/10/00.
As for your advice to big on buying a Toyota, that isn't an option for us that use campers and pull boats. As for Ford, go check out the Ford-Diesel.com and read the 50 page thread on the cackle and idle knock, not to mention if you tow and use an auto tranny expect it to go out every 15-20K miles. They all have problems, it is how they handle them.
In my case GM did the right thing. It most likely can be attributed to an aggressive and fair minded service manager, (mine was).

losangelesemt

" My point is that all you who are posting who do not own GM truck. Get out of here! "

I know it may come as a shock, but there are knowledgeable people in these threads who can contribute, and guess what, they might not own GM trucks.

txyank1

I read and post on Ford, Dodge and PT Cruiser threads but I don't own them. BUT, I'm interested and I don't go in to stir things up. I'll admit sometimes it's difficult to keep your fingers off the keyboard.

nlt

I am really speaking to the people who slam GMC.
Because they don't have one.
Anybody posting something helpful is always welcome. I apologize
My comments are not directed at the jerks who just want justify their own trucks.

buddyandannie

I am also experiencing the engine clatter generally during acceleration. It is being serviced today and I am curious do see the results. They were suggesting a top engine soak to help solve the problem. At 22K miles, this is absurd and to suggest that it will need this treatment routinely is unacceptable. I took in in about 6K miles ago and they claim they couldn't hear it but to use a mid-grade gas. I suppose this is the Great GM Feeling they advertise. Please respond if you have also experienced this problem and any cure, excluding additives every 2000 miles.
Steve

sonjaab

I have a 01 6.0 ....No spark knock using
the cheapest gas I can find. Sometimes
when towing in the summer I have minor
pinging...But a tank full of premium gas
solves that problem ! As far as cold start
knock it is very minor to me cuz I live in
Frozen New York and most of my vehicles
do it in the winter ! Yea I had the Chevy
dealer put it in writing too ! You know
the story "NO PROBLEM FOUND" from mr dealer !
As far as warm engine lifter knock......
Its not the lifters but fuel pulsing thru
the fuel rails and injectors. But It sure
sounds like noisy lifters tho. Mechanic
at GM dealer gave me his stethoscope to
listen to the noise and he was right !
..........Geo

allchevy

I'snt it interesting how none of our GM engines knocked,rattled,clattered,pinged or idled rough when they were on the dealers lot??
This kind of premeditated engineering bandaid reeks of cover up at the highest level.
The sad thing about dishonest Enron style corporations and their cover up support teams is that it costs hard working Americans so much to clean up the mess when it's over.

seelig

i share your experience with pinging on my wifes '01. took it in and they said it was normal and that they all do that........ok, so now lets take a drive in my '00 rado that doesn't ping. after that i asked the shop foreman which truck was going to be fixed?....the '01 that pings (they all do it), or the '00 that doesn't ping. if they all ping, then my '00 must be defective right, cause it doesn't ping. they are currently researching the problems with the wifes '01.
pinging is not normal, and it will cause engine damage. GM really needs to get their act together, or they might just end up with more than a bloody nose on this one.

sonjaab

I hear ya ! But ALL big companies
gotta cover their butts.
Toyota and the sludge deal in motors.
Ford and faulty ignition switches
and lets not forget those pinto gas tanks.
GM sidesaddle gas tanks too...
But you know how it goes....
The working man or woman PAYS !!!!!!!!

whatsachevy

My '01 Chevy 2500HD 4X4 EC SB 6.0/4.10 started pinging around 5-6K (if I remember right). I tried 89 octane and it helped slightly but the pinging was still there (even without a load). I took it into the dealer around 7K and had the service manager go for a ride with me. He agreed that it was not normal. He said the computer needed reprogramming. He did ask me how long it had been doing this. A top soak is usually recommended if it has been pinging for a longer period of time. Pinging creates a carbon build-up in the cylinders which the top soak is supposed to take care of. He told me if it was his truck he would not do a top soak if it had only been pinging for about 1K, but he would do it if I wanted him to. I declined the top soak and had the computer reprogrammed. Since then, I have burned nothing but 87 octane with not even the slightest pinging (now around 14,700 miles). My service manager has always been pretty honest with me from what I can tell. He helped me get the 5yr/100K extended warranty on the engine. There has been some talk of the warranty letters not being worth anything. I asked him about that, and he told me I have his word that he will honor the letter if I ever need to have engine work done. I think, from what I have read here, your dealer and service department make all the difference in the world how you are treated by GM when it comes to problems.

obyone

And also understand that the service manager is an employee of a company who's policy and decision making that he still has to follow no matter what he says. That is, of course, if he values his job.

txyank1

really good (IMO), co-operative. Service Reps. I've dealt with don't stay around. Guess they're too Customer oriented!

bigblackmotor

For folks who are interested, there is now a borescope photo of cylinder bore damage caused by piston slap on a 2001 8.1 Liter GM engine with only 14K miles in addition to the .wav file of the sound at http://www.gmpistonslap.cjb.net

This is the only knocking cylinder which is approximately down 10 PSI on compression when compared with the average of the other cylinders. The engine knocks at all temperatures (although louder at cold start) and is now using approximately 1.2 qts per 2K miles of oil. Borescope inspections of the other non-knocking cylinders showed only the original factory machining.

rayt2

Great documentation on your site, http://www.gmpistonslap.cjb.net

Keep up the good work, eventually GM is gonna have a hell of a lot of explaining to do to the public on this one, and the states attorney generals who have been contacted by dissatisfied loyal customers.

Ray T.

allchevy

Today I asked the Environmental Protection Agency for a emission waiver for the slapping knocking, blow by, polluting engine in my new Chevrolet Silverado.The reason I will need it,I explained, is because General Motors is not interested in fixing the undersize loose fitting pistons that cause the wear problem.

ryanbab

A waiver cause your truck is polluting?

This seems to be getting way out of hand

smith53

sounds like he lives in an area that requires emissions testing. the area i live in requires them also but temporary waivers( 1 year) are granted if you spend a specified amount of money trying to get the vehicle to pass..

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markbuck

I had a '99 4.8L 1500, put close to 40000 miles on it, pulling a fairly big trailer. Fought some engine ping, but solved with higher octane gas.

Traded it for a CC 2500HD with a 6.0L. Now at 20,000 miles, pulling same trailer. Same light ping problems, but not experiencing any engine knock/piston problems.

Previous several vehicles were Fords, Isuzu's, Mazda's.... Currently VERY HAPPY with my experience with GM's new LS1 motors.

So, guess I'm sorry for yawl, but I can't help but wonder if proper breakin, warmup, doesn't have something to do with your problems........

ryanbab

I live in an area where you have to be emmission tested (5 yrs after you buy a brand new car)

I HIGHLY doubt a knocking ticking or otherwise engine would cause you to fail

rayt2

Mark, Proper breakin was never an issue with my knocker, I gave it 500 tender break in miles, changed the oil/filter then drove it as I would any other vehicle. The knock didn't develope till around 17k miles, it now lasts longer during the cold start-up then in the beginning. But hell I got that good ole letter from GM for extending my engine warranty. That & a quarter I can make a phone call to someone who cares! LOL

Ryan, You won't know if emissions are effected till the test is done now will we ??? Only thing we have as positive proof (at least on one engine) is the borescope results showing the scoring of cylinder wall.
Like I said before I'd like to keep this truck till 2010, just not sure if engine is gonna hold out till then. But then again maybe GM will have been put on the carpet and forced to address the issue once & for all. I still love everything else about this truck otherwise.

Ray T.