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Owners of some of General Motors Corp.'s most expensive light trucks, including the GMC Yukon and Chevrolet Silverado, say the vehicles they paid more than $30,000 for may be worthless now because of loud, irritating knocking noises in their engines, lawyers tell the Free Press.

Thousands of vehicles, most from the 1999 to 2002 model years, may be affected, say the lawyers, who specialize in lemon law. They say GM is quietly buying back some of the vehicles.

Some experts say the knocking, caused by contact between the engine's pistons and cylinders, may be damaging in the long run.

GM acknowledges the problem, which it said surfaced when it moved to a new family of engines, but says it does not affect engine performance and that it was corrected in later-model vehicles.

The problem is, there's no apparent fix for the earlier models, leaving buyers angry and worried. "I paid almost $35,000 for this truck. The truck is almost worthless," said Greg MacNeil, who purchased his 2001 Chevrolet Silverado two years ago. "In good conscience, I couldn't sell this truck to someone else."

When MacNeil bought the truck, he dreamed it would take him on long trips to northern Michigan.

But when his engine started knocking just two months after he bought it, he barely trusted his black pickup to take him 30 miles to work.

"I've been afraid to drive the truck up north," said MacNeil, who lives in Brownstown Township. "I only take the truck back and forth to work."

Ron Martiny of Oshkosh, Wis., had just returned from Florida in February 2002 when his Silverado's engine started knocking. His dealer told him the sound was normal. But a month ago, GM bought back his $40,000 truck, he said.

It's unclear exactly how many vehicles or how many kinds of GM vehicles have this noise, but customers and several lemon law lawyers say the problem occurs within months after customers drive them off dealer lots.

Lemon law lawyers say they occasionally get calls about engine knock with other automakers' vehicles, but they report an unusually high incidence of this kind of problem with GM vehicles.

"In the last year, this problem became really obvious," said Brian Parker, a Michigan lemon law attorney.

According to dealer service bulletins obtained by the Free Press, vehicles with the engine knock problem include 1999 through 2002 Chevy and GMC pickups and sport-utility models with 4.8-, 5.3- and 6.0-liter V8 engines.

The bulletins say that the noises are not detrimental to the vehicles.

But experts say knocking is abnormal and can damage the engine.

What's all the racket?
GM officials say carbon and the amount of clearance between the piston and the cylinder wall are the primary causes of the knocking.

Usually, when the piston moves up and down in the cylinder, a component called the ring land, which is near the top of the piston, does not come in contact with the cylinder wall. But when carbon forms on the ring land over time, the ring land gets wider and begins to hit the wall. When the two come in contact, the driver will hear the knocking noise, said Chris Meagher, assistant chief engineer for GM's small-block V8 engines.

Spacing is also an issue, because when there's too much room between the piston and the cylinder wall, a greater amount of rocking can occur and can cause more noise, experts say.

GM spokesman Tom Read said GM has addressed the issue by making design changes to the piston in some 2002 vehicles and all 2003 vehicles with the noise. GM has cut the amount of space between the piston and the cylinder so that the amount of rocking is reduced. The changes also keep the ring land from contacting the cylinder wall when carbon builds up, Meagher said.

Read said the knocking issue came about when GM started making a new family of truck engines in 1999. The company, however, promises that the knocking won't cause any damage to the engine because the carbon that has formed on the ring land isn't hard enough to damage the cylinder wall.

"Current analysis of 150,000-mile and 300,000-mile engines that have exhibited cold start noise show no significant wear," Read said.

And despite the controversy, GM's trucks got high marks in J.D. Power and Associates' 2003 reliability and dependability surveys. The Silverado, for instance, ranked second in initial quality in the study's full-size pickup category.

The noise, nevertheless, is irritating to consumers who have spent so much to purchase the vehicles.

"It's embarrassing," said MacNeil, who is suing GM. "If you accelerate, you can hear this vehicle 100 feet away."

There's also a question of durability. While it remains unclear whether this knocking causes damage, lawyers and consumers say the piston's contact with the cylinder wall can't be good.

Knocking, for instance, has been known to cause damage to the piston, and in some cases it has resulted in premature engine wear.

Customers in an uproar
Ron Martiny, who bought his Silverado in February 2002, said he took his truck to the dealer after he noticed the knock and the service manager told him the sound was normal.

Then, in July of that year, the dealer talked to a GM customer assistance manager about the problem and later that month, Martiny got a letter from GM's Chevrolet division offering him a 100,000-mile warranty.

But Martiny said he didn't want the warranty because he planned to drive his vehicle far beyond 100,000 miles. He sought legal help in early 2003, and shortly after the automaker came with a $3,000 settlement. Martiny turned the money down.

According to Martiny and his attorney, Vince Megna, GM finally bought back the truck about a month ago. The company paid Martiny's $20,000 loan balance, plus another $20,000 and took care of his attorney fees.

Lemon law lawyers say this process is typical. GM usually offers consumers a 100,000-mile warranty to settle the matter. And when that's not good enough, the automaker offers consumers some sort of cash settlement for the noise, which can range anywhere from $2,000 to $5,000, according to consumers and lawyers involved in the cases.

When the cash doesn't resolve the matter, GM usually decides to buy the vehicle back, Megna said. Megna said the cases usually don't even make it to court.

"They know when these are filed, they aren't going to win these cases," said Megna, who practices law in Wisconsin.

Dan Powell, who lives near Orlando and owns a 2001 Yukon XL with an engine knock, was so incensed by the knocking that he created a Web site, www.pistonslap.com, which discusses the engine problem and seeks feedback from others with the issue. Powell is also suing to get his money back for the vehicle.

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This is what I have been talking about forever, with our 2001 Silverado!!!!!
 

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Hmmmm,

Suing, wow, kinda childish suing for something dumb like a knocking engine. The old big blocks were notorious for doing it... as long as it stops knocking after the truck warms up, yer all right. Some people are unbelievable. I guess thats why most newspapers are written on a 5th grade level... because aparently thats how majority of people think.

Sorry to sound so bleak, just frustrated sometimes with people. I know I shouldnt bash people like that....

IMO, get over it, let GM pay to get a new engine or replace the pistons and extend out the warranty.

God Bless
 

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Discussion Starter · #3 ·
Originally posted by manofgod_75002@Nov 15 2003, 02:15 AM
Hmmmm,

Suing, wow, kinda childish suing for something dumb like a knocking engine. The old big blocks were notorious for doing it... as long as it stops knocking after the truck warms up, yer all right. Some people are unbelievable. I guess thats why most newspapers are written on a 5th grade level... because aparently thats how majority of people think.

Sorry to sound so bleak, just frustrated sometimes with people. I know I shouldnt bash people like that....

IMO, get over it, let GM pay to get a new engine or replace the pistons and extend out the warranty.

God Bless
Sorry, but I disagree. Our truck has had way more wrong with it than just the knocking. I am on those people with knocking engine side, I agree, you don't pay $30,000+ for a truck that is a piece of you know what! GM gave us the ext. warrenty, but why would we pay $50 everytime! And they are not taking to engine out f our truck, jeez, its only got 20,000 miles! WE want a replacement.. And if you read the whole article, it says that there was to be updated pistons in the Spring/Summer 2002, well its almost 2004, and still no pistons....
 

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If I read the article right, those were to fix the ones just coming off the line. I don't think there's a fix for existing trucks; that's why they're offering to buy them back. Personally, something like this is to be expected when they go to an all-new engine. Yeah, it shouldn't happen, but mistakes are made. We all know GM is guilty of it's fair share of mistakes and then some. NSAP, not to be offensive, but if you don't like it, have GM buy back your truck, and use the money to buy a brand-new one. The new one's should be alright.
 

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Discussion Starter · #5 ·
Originally posted by nightwave@Nov 15 2003, 01:10 PM
If I read the article right, those were to fix the ones just coming off the line. I don't think there's a fix for existing trucks; that's why they're offering to buy them back. Personally, something like this is to be expected when they go to an all-new engine. Yeah, it shouldn't happen, but mistakes are made. We all know GM is guilty of it's fair share of mistakes and then some. NSAP, not to be offensive, but if you don't like it, have GM buy back your truck, and use the money to buy a brand-new one. The new one's should be alright.
We are vurrently working on getting a replacement...
 

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I agree that this thing should not happen in such an expensive vehicle. It's small wonder peeps are going over to Toyotas and Hondas. Doesn't GM test their engines for these things. I love GM cars the best but it is sometimes hard to explain that to people that I recommend cars or trucks to and they get a knocking truck engine, a 3400 with bad pistons or a blown intake manifold and now ecotecs that need to have their cylinders re-lined because of knocking noises! Really this is getting rediculous. Now I realize GM has some good engines such as the 3800 and the northstar v8 but even those have had troubles. My GP was recalled for the upper and lower intakes, and then for the throttle body. Also the oil pan was seeping. Aside for that it was a good engine. Some others weren't so lucky and blew piston chunks up into the manifold cause it was ingesting antifreeze. Well hope GM makes some strides in the Lutz era in this department.
 

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Discussion Starter · #7 ·
Originally posted by ponchoman49@Nov 15 2003, 09:27 PM
I agree that this thing should not happen in such an expensive vehicle. It's small wonder peeps are going over to Toyotas and Hondas. Doesn't GM test their engines for these things. I love GM cars the best but it is sometimes hard to explain that to people that I recommend cars or trucks to and they get a knocking truck engine, a 3400 with bad pistons or a blown intake manifold and now ecotecs that need to have their cylinders re-lined because of knocking noises! Really this is getting rediculous. Now I realize GM has some good engines such as the 3800 and the northstar v8 but even those have had troubles. My GP was recalled for the upper and lower intakes, and then for the throttle body. Also the oil pan was seeping. Aside for that it was a good engine. Some others weren't so lucky and blew piston chunks up into the manifold cause it was ingesting antifreeze. Well hope GM makes some strides in the Lutz era in this department.
My GP was also recalled for the same reason... <_<
 

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My LS1 has never had a problem with piston slap. It makes a very faint knocking noise when it's cold, but in about 15 seconds or so that goes away.

I'm lucky I guess.
 

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It seems that too many people start using the words "lemon" and "defect" in the wrong manner these days, compared to prior times before the legals were really keyed into these things. Just my observation.

Sure, typically a piston "knock" or "slap" would be due to excessive piston to cylinder wall clearance, but a friend built a 426 Hemi with used pistons and approximately .008" clearance where the factory spec was about half that. No durabilitiy problems at all.

In the days of the original LT-1 350s and forged pistons, most of them had a cold piston knock when the engine was first started. Forged pistons needed about .004" clearance so that when they warmed up, they'd be correctly clearanced. No durability problems there either.

In the model years prior to about 1970, most of the Chevy pickup truck engines were also set up with about .004" piston to cylinder wall clearance. This was explained as "you run them looser for the more heavy duty applications" by a Chevy dealership service manager back then. I initially thought it was a bs explanation until I found the looser piston clearances in a Motor Repair Manual, whereas the car engines were set up with the normal closer piston clearances.

But when normal engines of that era with cast pistons had piston knocks, it was usually due to other issues (i.e., "galling" of the piston skirt) which did require disassembly and replacement of pistons or a replacement short block assembly.

I know that many people start screaming and hollering about any engine noise that seems "abnormal" to them. I suspect that if you remove the full engine cover on most overhead cam and other port fuel injected engines and hear all of the injector noise, it might be interesting. In the specific case of the GM Vortec engine family, GM has made several changes to the pistons and ring packages since the engines were new--and they still are.
In the case of the carbon buildup, there is a service bulletin out which addresses carbon buildup on the upper piston rings with respect to oil consumption issues. That same procedure might be used on the Vortecs too, if necessary.

But what really ought to be addressed is why with the "cleaner burning fuels" we have today, there is any carbon buildup at all in these fully computer controlled engines? Are most of these issues from metro areas with reformulated fuels or in other places? These might be questions that no one will answer anytime soon.

In some cases, it seems that people are blowing things out of proportion as to their alleged "loss of value" and "loss of confidence" with respect to their vehicles. I might wonder if these consumers might be having "buyer's remorse" for some reason and are keying on the engine noises way too much? The fact that GM is offering them a 100,000 mile engine warranty should tell them there will be no problems. The fact that some have replied that they desire to keep their vehicle well past that number of miles tends to indicate that they might well be having second thoughts about spending a significant amount of money in the first place.

Many see the buyback as an admission of guilt. In reality, as "consumer miles" are different from "proving ground" miles, buying back the vehicle or putting in a current production engine engine with all of the upgrades is the only way for GM to get a better handle on the problem or to determine just how much of a problem there really is and to what degree of seriousness. Also, if there's some other vehicle related problem that magnifies the engine sound, having the complete vehicle is the only way to do a full engineering analysis without keeping the customer's vehicle out of service. Hence, buy it back and put them in a newer vehicle.

If you check out the www.pistonslap.com website, you will find that Ford had some piston noise issues too. Many called these engines "defective" when they were fine other than the noise issue. Sure, they could be expected to be quiet, but some are not and a non-durability noise does not really justify the word "defect" or "lemon" as the utility of the vehicle is not affected. If a piston cracks and causes engine damage, that would be a defect which resulted in component failure similar to if a connecting rod bolt broke.

And then there are the still recurring head gasket situations with Chrysler's 4 cylinder engines. What is suspected to be a simple oil leak turns out to be a head gasket that lets oil leak from a somewhat non-critical area. In many cases, more of a nuisance than anything else--kind of like some piston noises.

Just some thoughts,
NTX5467
 

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Originally posted by manofgod_75002@Nov 15 2003, 03:15 AM
The old big blocks were notorious for doing it... as long as it stops knocking after the truck warms up, yer all right.
Give me a totally new design in the GM Inline-6 engine family - or the new CTS 3.6L over these 30-50 year old "redesigned" engines any day. Smooth, modern, and designed from the ground up on computers - that's what I like.

And people wonder why I tire of seeing GM go back to the V8 well so often.

This whole flap does remind me of the Toyota engine "sludge" problem, though:

http://yotarepair.com/Sludge_Zone.html
 

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Discussion Starter · #11 ·
I myself am not affiard to call our truck a Lemon... ;) Here is everything that has been wrong with it:

Hesitation upon accleration
knocking in engine
Power-Seat motor needed replaced
Oil Leaks
Rocker Arm broke
The heads were pulled at only 5,000mi!!!!!
the back bench seat makes a lot of noise when driving
the back brake rotors needed replaced after 2,000
the crossover pip and 2 sensors were replaced


Practically, everything on that truck is different, with the expection of that lovely Vortec engine... <_<
 

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Depending on the state in which you live, you have specific time frames for reporting and filing for a claim under the consumer protection acts.

In NJ, you have to have 3 or more repair attempts in the first 18mos/18k miles, and report your claim with in 24mos/24k miles from the time the vehicle was placed in service. The vehicle must also be used for personal use only.

The 3 repair attemps must be for substanitally the same repair, and one that affects the safety, drivability and/or value of the vehicle.

If the repair was done and the problem is not *currently* on your vehicle, the manufacturer and the dealer have performed thier duty to you as the consumer.

You might not be happy about having a problem, but that is what a warranty is about.

:blink: If you don't want engine noise, buy an electric golf cart. :blink:
 

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Discussion Starter · #13 ·
Originally posted by JDogg@Nov 16 2003, 09:09 AM
Depending on the state in which you live, you have specific time frames for reporting and filing for a claim under the consumer protection acts.

In NJ, you have to have 3 or more repair attempts in the first 18mos/18k miles, and report your claim with in 24mos/24k miles from the time the vehicle was placed in service. The vehicle must also be used for personal use only.

The 3 repair attemps must be for substanitally the same repair, and one that affects the safety, drivability and/or value of the vehicle.

If the repair was done and the problem is not *currently* on your vehicle, the manufacturer and the dealer have performed thier duty to you as the consumer.

You might not be happy about having a problem, but that is what a warranty is about.

:blink: If you don't want engine noise, buy an electric golf cart. :blink:
The hesitation, knocking, and seat noises can't be fixed.... GM has told us that those are normal, and as we told them, if that is normal we wish we would have got an ABNORMAL truck.. :lol:
 

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My car is making this terrible loud growling noise whenever I tap the accelerator.

It's coming from the back, I think my car might be a lemon.

I know I should have gotten that toyota...
 

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Originally posted by TAFreak@Nov 16 2003, 07:37 PM


I think my car might be a lemon.

I know I should have gotten that toyota...
:lol:
 

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As an owner who has experienced a "buy back" first hand on my 2000 Silverado Z71 Extended Cab. I can attest that my truck was a lemon. It was in the dealer for problems over 75 times in less than 2 years and 21,000 miles. Everything on that truck broke. From the Engine failure before the first oil change to the rear end locking on dry pavement, transmission replacement at 16,000. Some might say sense it was mechanical problems that it was probably driver abuse, but that could never explain door hinge failuers, SES light 14 times, Rear window leaking like a waterfall, bed welds coming lose, BOTH pwr window motor failed, Horn stopped working etc. I could list on and on and on. :angry: So in my opinion anyone who shells out $30,000 and has this much trouble should be able to call the truck anything they want, LEMON,FACTORY DEFECT,POS, FRIDAY @ 5 Special....

I traded for a 2001 2500HD while this truck has not had the major problems that the other truck has, it has been to the dealer probably 15 or so times for problems such as the seat belt breaking,AC Compressor Failed, Idler Tensioner Failed, Extended Cab Check link replacement, Cruise Control Module Replacement,etc
and yes it has the Piston Slap. General Motors did give me the 6yr/100,000 mile warranty which I appreciated that way when I sell it I can pass that on to the next owner so maybe he wont be so worried about it blowing up.

My whole point is that Iam a Die Hard Chevy Truck Fan but when I traded my 1989 with 151,000 miles for my 2000 Silverado I was expecting a better truck then I had. Iam not so sure if this 2001 is a better truck than my 1989 model but, I know it is better than my 2000 which was not much more dependable than a broken stick !!!

If anyone from Chevy who is apart of building the next Silverado reads this I have some information for them. There is going to be a revolution in the Truck Industry the Japaneese are about to make their full scale assault on the Full Size Truck Market. If the New Nissan Titan will run 100,000 trouble free miles with minimal squeaks,rattles, etc You will lose customers !!! I know some of us die hards(me included) will still belly up to the Generals Table and take it with no lube, but there will be others who just wont do it. Your next Silverado Design had better be good because it going to have alot more competition then your current one !!

The 1999 Silverado Brochure said replacing a bench mark is never easy, but we built a better truck then the C/K series. Here is a news flash from a guy who has had both... Try Again You Didnt Do it !!!

I will now step down from my soap box :(
 

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Discussion Starter · #17 ·
Originally posted by HDROCK@Nov 16 2003, 07:28 PM
As an owner who has experienced a "buy back" first hand on my 2000 Silverado Z71 Extended Cab. I can attest that my truck was a lemon. It was in the dealer for problems over 75 times in less than 2 years and 21,000 miles. Everything on that truck broke. From the Engine failure before the first oil change to the rear end locking on dry pavement, transmission replacement at 16,000. Some might say sense it was mechanical problems that it was probably driver abuse, but that could never explain door hinge failuers, SES light 14 times, Rear window leaking like a waterfall, bed welds coming lose, BOTH pwr window motor failed, Horn stopped working etc. I could list on and on and on. :angry: So in my opinion anyone who shells out $30,000 and has this much trouble should be able to call the truck anything they want, LEMON,FACTORY DEFECT,POS, FRIDAY @ 5 Special....

I traded for a 2001 2500HD while this truck has not had the major problems that the other truck has, it has been to the dealer probably 15 or so times for problems such as the seat belt breaking,AC Compressor Failed, Idler Tensioner Failed, Extended Cab Check link replacement, Cruise Control Module Replacement,etc
and yes it has the Piston Slap. General Motors did give me the 6yr/100,000 mile warranty which I appreciated that way when I sell it I can pass that on to the next owner so maybe he wont be so worried about it blowing up.

My whole point is that Iam a Die Hard Chevy Truck Fan but when I traded my 1989 with 151,000 miles for my 2000 Silverado I was expecting a better truck then I had. Iam not so sure if this 2001 is a better truck than my 1989 model but, I know it is better than my 2000 which was not much more dependable than a broken stick !!!

If anyone from Chevy who is apart of building the next Silverado reads this I have some information for them. There is going to be a revolution in the Truck Industry the Japaneese are about to make their full scale assault on the Full Size Truck Market. If the New Nissan Titan will run 100,000 trouble free miles with minimal squeaks,rattles, etc You will lose customers !!! I know some of us die hards(me included) will still belly up to the Generals Table and take it with no lube, but there will be others who just wont do it. Your next Silverado Design had better be good because it going to have alot more competition then your current one !!

The 1999 Silverado Brochure said replacing a bench mark is never easy, but we built a better truck then the C/K series. Here is a news flash from a guy who has had both... Try Again You Didnt Do it !!!

I will now step down from my soap box :(
I deffinatly understand what you aare going through!!


By The Way: the 2003+ Silverado's are MUCH more relible and not soo "junky" ;)
 

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GM said they were going to build a more durable small block than the first generantion?

The real problem is in the short piston skirts used in these engines, and I think that the problem will always be there, even with new pistons installed, so whats the answer?

what really concerns me is the fact that GM is saying that it is "normal" because it is not but it is not known if it will effect the durability and I haven't yet seen any engines actually fail because of this yet.

so GM own up to this problem and show that you care about your customers.
 

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Discussion Starter · #19 ·
Originally posted by doh@Nov 17 2003, 09:47 AM
GM said they were going to build a more durable small block than the first generantion?

The real problem is in the short piston skirts used in these engines, and I think that the problem will always be there, even with new pistons installed, so whats the answer?

what really concerns me is the fact that GM is saying that it is "normal" because it is not but it is not known if it will effect the durability and I haven't yet seen any engines actually fail because of this yet.

so GM own up to this problem and show that you care about your customers.
Good Point! :D By the way, some experts say that the problem makes the trucks age quiker than it is projected to... <_<
 
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