Engine Knock on 2001

[derk3]

Hello there,

Has anyone had a problem with an engine knock? My 2001 has this knocking sound in the engine. Kinda sounds like a dull lifter knock, but coming from the bottom of the engine. Particularly loud when it is cold outside and just fired up, and faint when warm. The car has been babied from the time purchased brand new. I've scheduled an appointment with the dealership for this week, just wondering if anyone has heard of this. Thanks,

Derrick

[danl72]

I'm not sure, but someone will respond to your post who can help you. Just be patient. Good luck with the dealer. Do you use premium unleaded (92). Some times the engine pings and knocks if 91 or higher is not used.

[derk3]

Thanks for the encouragement. I always use 92 or 93 octane when filling up. I just read a thread about 3 months ago dealing with the gentleman with the blown engine and the legal problems with GM. I'm sure mine is not to that point (I hope not), although the knock has gotten proggresively worse the past few thousand miles. I'll let you know the outcome...

[Rob]

Derrick,

Have you brought the car to a dealership to have them look at it?

[derk3]

Rob,

I have an appointment for Tuesday.

[c4c5specialist]

Hi there, and welcome,
As for your issues, what is the mileage????
How long have you been experiencing this condition???
How long after initial cold start does the noise last, in minutes??
Please let us know what you have, c4c5

[derk3]

Hello again,

It's a C5 with 8000 miles now. There was always a faint "slap" in the engine, but the knock started about 1000 miles ago and has gotten louder since. It will last for about 8-9 minutes, then into a faint knock when it idles at about 1100 RPM. Is this a normal function?

[Black Ice]

I have had this knock from new on my 2001. It starts about 40 seconds after cold start up. It is really noticable for about 5 mins there after. Then its still there hot but really faint. I was told there was nothing wrong with the engine and is a trait on cars with no piston skirts. GM changed the design in 2000. They were to have coated the pistons with something for 2002 to reduce this noise. I must admit every time I hear it on start up Im troubled by it.

[c4c5specialist]

While you issue is not uncommon, your clue here is the getting louder as time has gone on. Here are the details
As the design of the pistons have very little in the way of piston skirt, they do rock slightly in the bore. Now, this is the design, and will not create any problems, but as you mileage grows, so does the deposits within the combustion chamber. So what this does it change the way the piston moves, causing the increased noise.
I would say that they will most likely do a top engine cleaning, and have it soak over night, to see how it does.
Please let us know how you do, c4c5

[Black Ice]

I also had this same problem with a 2000 S10 Blazer. They did many Top engine cleanings. Nothing helped. They ended up replacing the engine and that did the trick. Then different problems came up due to the engine not being installed properly and I ended up suing GM they setteled out of court for 60K

[derk3]

I would sure hope it doesn't come to that. I can't comprehend the thought of a new engine being put in my baby. :( My appointment was moved to next week because of me, but we will see what happens.

[Black Ice]

Oh I would never go through that again. I should have just traded the thing in, it took 14 months to get resolved. I had another 2001 a coupe that had the knock as well but not quite as pronounced. I had Dave Peice (Chevrolet Brand Service Mgr. from Warren Mich.) look at mine and he called it "piston stack up". He explaned that sometimes a block may have a bore that is just a tiny bit to large and the piston put in that bore might be a little off as well (too small) and this is known as "stackup". This causes piston slap and assured me that it will cause no harm. He told me that the 2002s had this problem addressed with some type of coating to the sleeves and pistons. This leads me to think the problem or as GM would like to address it as an "annoyance" is fairly wide spread. We just got cars that are a little louder. (Of course I would get the noiser one)

[c4c5specialist]

Black Ice,
As for the information that Mr Peacy, has provided to you, this is true, however, this is a different concern, as you saw from the post, this condition has worsened over time, due to carbon build up. Normally, stack up does present itself, but does not get progressively worse, it stays at one noise level, and does not increase. However, the principal is the same, piston movement.
As for your Blazer, these are 2 different engines, and should not be confused.
The same condition presents itself, as movement of the pistons in the bore, is aggravated by the carbon, thereby, increasing the noise.
Please do not consider this aggressive, this is just the way this design is, and the pistons, and rings were updated for the 02 model year.
Just a Mr Peacy has said.
Best to all, c4c5

[Black Ice]

Peacie also said it could be a wrist pin problem.

[Black Ice]

So What's the latest??

[derk3]

I had to move my appointment and it's going in Tuesday, we'll see then. I'm not too optimistic given what everyone has said, but you never know!!

[derk3]

Ok, here is the latest on the knock... They say that I have a bad lifter and possibly a vavle problem. They have ordered new lifters and have scheduled to put them in next Wednesday. They need about two days to do it. Whew.....Just the thought of my heads coming off makes me sick to my stomach. :puke He assures me that the best will be working on it (like he'll tell me his worst guy will be on it) and it'll be fine. I guess we shall see. Thanks everyone for the advice and info here.

[Black Ice]

Oh please keep us informed. I have this same noise. I would like to see how this works out for you. I may be next!!!

[Hib Halverson]

c4c5specialist is right.

Some pre-02 Gen III passenger car engines have a problem with "cold piston knock". It has to do with the shape of the piston, the piston-to-bore clearance and how that clearance changes as the engine warms.

It is not a problem, just an annoyance.

All the symptoms listed here speak of a noise that is louder at start-up than it is after the engine warms. That is typical of cold piston knock and NOT typical of detonation or "spark knock".

The piston design used in the LS1/6 engines was changed for MY02 to eliminate this problem. Details of that can be found in an article on the 02 LS6 in the new GM High-Tech Performance that should be out about now. Information on the new piston can also be found at:http://www.c5registry.com/2k2z06/

[Black Ice]

Very interesting Hib, My 2001 was made in mid May and GM claims the pistons were changed in Mid April and I still have the knock as well.

[Black Ice]

Hib I like the way GM says there is no duribility problem with the "ring thing". What a crock of Sh-t. What they did not mention is all that oil passing through there flapping rings are going to wreck the sensors the cat's, plugs and other components down the line. is GM going to cover these things for oil fowling after the warranty is up?? I see a class action lawsuit here somewhere....

[c4c5specialist]

While I can understand to an extent, Black Ice, and the fears that you have voiced, I cannot concur.
PCM diagnostic function checks for slow, or non response of o2 sensors, for which there are numerous codes.
Also, non functioning of catalytic converters, which will also be tested on the next appropriate drive cycle, and set a few more codes. If any sensor, or converter degrades, due to carbon contamination, would it not show up before the end of the oil consumption test?? Of course it would. These codes for these failures are classified as a type 'A', which per EPA guidelines, MUST turn on the SES light, on the first failure. Thereby, storing a failure record in the PCM.
Your converters are covered by a 8 yr, or 80000 miles warranty. Once your converter lights off, at about 450-600 degrees, all excess carbon is burned off, as a result of the increased oil consumption. If it was to coat the converters, your p0420 or p0430 would set for converter efficiency. As long as you have not modified the converter assembly, or added cam, heads, or nitrous, you will not have an issue.
YOu will find that most, if not all of the ring replacements, have occured under 20k. After we do a ring replacement, we MUST DO A FULL DIAGNOSTIC DRIVE, in order to confirm that there are no further issues, and that the vehicle is repaired correctly the first time.
From the facts above, there will a few cases, where the service may be lacking, however, for the 99% of repairs, you will not have any issues further.
These are my reasons for feeling that the idea of any kind of lawsuit, unless because of poor service, would not be proper in this instance.
Best toyou, c4c5

[Black Ice]

Well just the FACT that GM changed the ring design tells me there was something wrong with the 2001 design. I can not believe that oil blowing by the rings would not cause some long term damage to components and sensers down the line. The original design intent was not for the motor to ingest a quart of oil in 800 miles. I think GMs arrogence to this matter is reason enough for a class action suit. I don't know of any other 2001 auto in the 50K+ price range that burns a quart of oil in 800 miles. DO YOU???

[c4c5specialist]

Hi there,
The first Z3 carried engine problems and all were recalled, and engines installed.
911 had breakin issues, and pistons/ring packages were installed.
As for arrogance, I dont think so, as when the first documented cases were found, engineers were quickly on the scene, attempting to determine the correct course of action. I know, I was right in the middle of it.
All redesigned parts must go through EPA validation BEFORE THE FIX IS ISSUED. They cannot issue a correct repair before such time as the repair has been verified. They must follow legalities, as must we all in the repair field.
These are simply facts, and I ask that they be taken as such, c4c5

[Black Ice]

THIS HAPPENED IN THE C5s FIFTH MODEL YEAR!!!! Why?? and now the owners get stuck holding the bag!! Most Chevrolet Dealers can't manage to make small repairs correctly let alone an engine tear down. I went through this with my 2000 blazer. This kind of engine problem should not surface in a platforms 5th year. PERIOD!

[Black Ice]

At least BMW admitted a problem and replaced engines. GM chooses to blame the consumer for driving a sports car to aggressively, and says using a quart of oil in 1000 miles is normal. HOGWASH. I have owned SEVEN C5s including the 01 oil burner. NONE of my other C5s used oil not even my very early 1997 vin 1100. My 2001 LS1 based Tahoe has 3000 miles on the last oil change it has used LESS then 1/4 of a quart of oil. GM needs to RECALL all 2001s for a re ring. I am working on this with my lawyer, Look for my class action law suit soon.

[Rob]

Well....now I have to ask. You've owned 7 C5s......were they all "oil burners"? If you had similar problems with all the C5s you owned, why did you continue buying a car from that platform each time? I'm just kind of curious because personally speaking, if I purchase the same product 2 or 3 times, and all 2 or 3 times, the product fails, I wouldn't buy that product a 4th, 5th, or 6th time after that.

[Black Ice]

I have owned 1 1997 2 1998 1 1999 1 2000 2 2001s. Only my 2001s burn oil. none of the other cars including 13 C4s ever burned oil.

[c4c5specialist]

GM engineers were trying to save gas mileage, and give us better performance, that is why the lower tension in the second compression rings. They try to give us better mileage, and your upset??
And it is not onlythe fifth year, the bulletin applies to cars back to 99. The major issue is that engines consistantly run over 3200rpm, will start to cavitate, and therefore, use oil. GM builds alot more vehicles than BMW or Porshe. The situation really presented itself with LS6, due to the higher peak torque, and horsepower curves.
And if GM didnt want to fix the issue, there would not be a bulletin for Camaro, Firebird, and Corvette. Your Tahoe is LS1 based, however, not the same. Camshafts, compression, calibration, and torque peak, gearing, and final drive are totally different, so you do not have to rev to 3200 consistantly to gain powerful acceleration
I would suggest that you sell your Corvette, and buy something else, as I feel you are being unrealistic. Everyone makes mistakes, even multibillion dollar corporations, and I dont know what you were fed at the place where you bought your car, but noone was blamed on this, but the rings, plain and simple. Your case is obviously different, because you were blamed, not the car. That was wrong, and I concede that.
However, give it some thought, as this is not something that I agree with. Due to the facts that I have listed. c4c5

[Black Ice]

I buy a $52,000,00 car it burns 1 quart of oil in 800 miles and Im unrealistic?? YES!!! Multibillion dollar Cos. DO make mistakes my point exactly. That's why I want all 2001 C5s to be recalled to REPLACE the rings or at the owners option take a 100.000.00 mile warranty on the engine and its components. GM will not admit there is an oil consumption problem. GM is openly blaming the consumer for there driving habits causing this problem. I want a court to examine the facts. I have employed an "Expert" to monitor oil usage on several (8) 2001s over a long period of time for court documents. What I can tell you so far over this 4 month period it isn't looking good for GM. Look for a class action suit headed for the courts in about 6 months. Oh yea better start getting ready to do a LOT of LS1 ring jobs :)

[c4c5specialist]

Sir,
If this is the case, that GM is directly blaming the customer for this issue, I will be interested to see exactly what documentation comes out of this suit, as to the GM document, which states this.
Because I, for one, have never seen any documentation that GM denied this and blamed it on anyone. And I have not heard one GM representative state anything about customers causing this issue.
Even the service bulletin, which has been release, says nothing about customer fault for this condition. It states that engines routinely run over 3200 rpm for extented drive times, nothing else. If GM didnt admit oil consumptions issues, why is there a published technical service bulletin??
And how did this go from piston movement issues, to ring overhauls???
c4c5

[Black Ice]

Please see Hib Halverson's informative article in the C5 registry. You can go to the link in this thread Hib listed it I think on page 2.

[c4c5specialist]

Sir,
In the remarks made by John Juriga, he states that this issue is caused by light load higher rpm usage, like not taking the car out of 2nd gear in city driving. He states that imbalance within the cylinders creates the condition, due to oscillation of the piston rings, under these type of driving conditions.
It is also stated that it mostly is due to driving styles, not that the customers are responsible for the problem, which aggravate the condition, to 600-800 miles to a quart. On those cars with this type of consumption, we were told to contact technical assistance. Now, we are instructed to install rings per GM TSB,01-06-01-023.
There was never a statement made that the customers are the reason this is occuring, nor that GM does not acknowledge the condition. On the contrary, they were working on this condition back in Jan and before. BUT, they had to be absolutely certain that the fix was correct, and that the consumption would be back up to the 1 quart in 2000 miles, which the rings do exactly that.
Not only based on the information on the internet, and within the GM, but on my personal experience.
With 15 ring jobs under my belt, all 15 cars have exceeeded 1 quart in 2000 miles, and every one is happy. This fix is it, and I stand behind the results, here, and across the Corvette community.
Best to you, c4c5

[Black Ice]

Isn't saying the customers "driving style", blaming it "Partly" on the owner? It really sounds like it to me. I still think its GMs duty to make ALL 2001s right. All 2001s then have the potential to burn oil with different owners/drivers. I will continue ahead to get all 2001s recalled for this problem, via a class action suit. We are also testing several cars to see if they meet EPA standards while drinking oil. I will leave you my E mail address Firstaid4film@aol.com. Thank you for your opnions and insights. Ross

[c4c5specialist]

Ross,
The key here is to learn from one another, and constant dialogue helps make our love of Corvette that much better.
Besttoyou, c4c5

[Black Ice]

Now there is a thread in the Corvette Forum about the knocking noise on 2002s!!!!!!!!!!! I thought GM fixed this... Yea Right.

[corvette0901]

After reading all the messages regarding the oil consumption and the ring replacements, can anyone tell me if they have actually been through this and what are the risks if I do this or don't do this. My dealership out here concerns me a bit and the thought of them performing what I call heart surgery on my first corvette leaves me very uncomfortable. Heavy Sigh