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Engine knocking / Tapping noise

313K views 319 replies 184 participants last post by  regionvoices 
#1 ·
I have an 02 trailblazer LS. Whenever It starts, its a smooth idle, but the engine sounds like it knocking really bad. It tends to go away during long trips. I;ve tried using better gas, but I noticed no difference. Is this noise normal or what? Thanks!
 
#2 ·
coastie22 said:
I have an 02 trailblazer LS. Whenever It starts, its a smooth idle, but the engine sounds like it knocking really bad. It tends to go away during long trips. I;ve tried using better gas, but I noticed no difference. Is this noise normal or what? Thanks!
Well, some of the '02's had a bad cylinder sleeve. Have you had your TB checked for this problem? What is the vin or serial # and someone here can check and see if your vehicle falls within the problem range.
 
#237 ·
IMO, since he did mention a smooth idle, and that the problem went away eventually (probably after warm-up), it could be an oil related problem. I have read that changing the oil filter to a better one allows more oil past the bypass valve when cold. Using synthetic oil may help too.

As for the initial noise, is it a tap or a knock? A knocking engine sounds like a person is hitting the insides of the engine with a hammer. A tapping is like much "lighter" in sound.

If he has a bad sleeve, I don't think he would be able to go on any long trips, as he mentioned he did. What actually happens is that the sleeves in the early I6 motors sometimes would actually slide down in the bore, allowing the top of the piston, and the rings, to come out of the top of the sleeve, and obviously cause all sorts of damage. The engine would be "blown", and no trips of ANY length would be possible.

I have a VERY early '02 (bought in July of '01), but luckily had no problems with this. I did receive the letter from GM about the possible replacement engine if I had this problem, but there is a time/mileage limit to it.

Hope this helps.
 
#3 ·
I was reading throught the forums and i saw the info about the vin numbers and the special policy number?I called Chevy and the said I might have the problem so i have an appointment monday. If this is the problem she said I could get a new engine. Do you know what the symptoms would be for this. I'm getting ready to move to alaska and a new engine wouldn't hurt my feelings to bad. Thanks!
 
#4 ·
:undecided I am having the same problem as coastie22, I made an appointment today. It sounds like a bloody Diesel engine for about the first 10 to 20 Minutes, before it warms up.

Here is my vin, do you think you could let me know if I am in the same boat.

1GNDT13S322525905

Russ
 
#5 · (Edited)
For all of you out there contemplating whether or not your engine has a cylinder sleeve problem, I have seen the results...pretty much looks like a hand grenade went off inside the motor. Here's what happens:
1). Engine running along fine...smooth, no noises, everybody's happy.
2). All of a sudden, a loud @*!$^~*+(!!# noise occurs. (the length and degree of this noise is determined by the prevailing engine RPM.
3). The engine immediately stalls and may or may not crank.
4). You get this shaking, empty feeling around your heart that travels into your intestines and to the tips of your fingers....The phrase, Oh" fu#k! may exit your mouth and the reality of what has just happened settles in.
5). Line 1 through line 3 takes about 10 seconds to occur.

What has just happened is a cylinder sleeve just decided to slide down the cylinder casting (engine block). There is now a gap of about 1" - 2" between the deck of the block and the top of the sleeve. As the piston travels up the cylinder, the top compression ring snaps out of the sleeve. At the end of this stroke as piston travel starts downward, this same compression ring snags on the top edge of the fallen cylinder sleeve. The compression ring comes to an abrupt stop, but the piston doesn't. This tears the top ring land and portions of the piston top off the piston. This debris sits at the top of the piston until the next upward stoke occurs. This time it's a little different as the debris on the top of the piston becomes an interference. This inability of the piston/rod (crankshaft) to rotate, stops the engine. If it all lodges in place, engine cranking will not occur...kinda like a stick in the spokes. Cranking the engine thereafter, if it cranks, is like pressing the "puree" button on the mixmaster.

Said in a nutshell, there is usually no forewarning of ill-running symptoms. Failure occurs hard and all at once.
 
#7 ·
Yes EnvoyGuy...you are right. It could be possible that some noise(s) may be present prior to complete failure. I like to call these noises before the failure...foreplay. My last post involved (4) failures I was part of. All the operators did not experience any "foreplay". The "****!..What was that noise! condition occured in all instances. 1 of the 4 experienced a no-warning failure during cold engine cranking. I guess it is best to say there is eminent failure and failure...failure which I was describing. I did review the warranty repair order regarding the engine replacement on your particular Envoy. There was no towing charges billed to GM at that visit, so I presume your vehicle was driven into the dealership...
 
#8 ·
Well i got it back. Of course all they went by was the noise. No borescope at all!And they wouldn't when i asked them to.They said no GM motor had that problem over 15,000 miles! They said they've never had to deal with it so they basically said, yea, we hear the noise, no clue what it is, but its not normal, have a great day!They have a special policy that they almost refuse to enforce.
 
#9 ·
Hey Mine in today too... They said that the noise is normal at Start Up. When things are warming up the rockers and lifters make noise. (or something like that). I dunno, maybe the I6 is louder then the V6 or V8 Engines that I have owned... But I swear the damn thing sounds like a diesel when its cold.. :undecided
 
#10 ·
It does sound like a diesal(sp*)but at least we all have it in common, so maybe its normal. I complained to corporate that they didn't borescope it. They shouldn't tell me the noise doesn't sound normal and then not check further. If you hear something wrong, find out what it is so you can eliminate the possibility of the "bad engine" O well, we'll see what happens when they follow up on the complaint.
 
#12 ·
coastie22 said:
Well i got it back. Of course all they went by was the noise. No borescope at all!And they wouldn't when i asked them to.They said no GM motor had that problem over 15,000 miles! They said they've never had to deal with it so they basically said, yea, we hear the noise, no clue what it is, but its not normal, have a great day!They have a special policy that they almost refuse to enforce.
BS!! Go to another GM dealership with the truck. Mine had the problem at 17,500 miles. Sounds like the dealer just doesn't want to work.
 
#213 ·
your dealer is full of crap....my buddy had a 06 civic w blown head that wasted the motor...the dealer swore this was an unheard of problem..denied him...even under wrnty....said he caused the probs....so his wrnty was void.....i clean a honda dealership at night aft all r gone....and the service bays r full of civics w blown heads and paper wk for new motors.....so he called corperate and got a new motor and trans w nw warnty.....your dealer is only trying to keep service warnty hours and cost down....dont give up....call corperate....good luck
 
#13 ·
Document ID# 1341528
2002 Chevrolet TrailBlazer - 4WD


--------------------------------------------------------------------------------

Special Policy Adjustment - 4.2L (LL8) Bore Liner Cracking #03019 - (Jun 6, 2003)
03019 - Special Policy Adjustment - 4.2L (LL8) Bore Liner Cracking
Certain 2002 Chevrolet TrailBlazer; GMC Envoy; and Oldsmobile Bravada

Condition
Some customers of 2002 Chevrolet TrailBlazer, GMC Envoy and Oldsmobile Bravada with 4.2L (LL8) L6 engine produced during the 2001 calendar year may experience cracking of an engine cylinder bore liner, resulting in engine noise, poor performance, and/or stalls with no engine re-start. Engine replacement is necessary to correct this failure.

Special Policy Adjustment
This special policy covers the condition described above for a period of seven (7) years or 100,000 miles (160,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. The repairs will be made at no charge to the customer.

For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after June 13, 2003, are covered by this special policy and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to June 13, 2003 must be submitted to the Service Contract provider.

Vehicles Involved
Involved are certain 2002 Chevrolet TrailBlazer, GMC Envoy and Oldsmobile Bravada model vehicles equipped with 4.2L (RPO LL8) L6 engine and built within the following VIN breakpoints:

Year
Division
Model
From
Through

2002
Chevrolet
TrailBlazer
22100007
22358861

2002
GMC
Envoy
22100001
22358855

2002
Oldsmobile
Bravada
22100005
22358857


Parts Information
Parts required to complete this special policy are to be obtained from General Motors Service Parts Operations (GMSPO).

Part Number
Description
Qty/ Vehicle

88984108
Engine, Goodwrench Service Replacement
1

12569542
Gasket Kit, Intake Manifold
1

88890561
Gasket Kit, Exhaust Manifold
1

24100165
Gasket Kit, Throttle Body
1

12378521 (US)

88901148 (Canada)
Sealant, RTV
As Required


Customer Notification
Customers will be notified of the special policy on their vehicles by General Motors (see copy of typical customer letter included with this bulletin -- actual divisional letter may vary slightly).

Service Procedure

Important
U.S. and Canada Dealers refer to GM Service Bulletin 02-07-30-029A . This bulletin reference is for the Powertrain Quality Center (PQC) at 1-866-654-7654. Prior approval for engine assembly replacement applies to this Special Policy.



Important
The labor time allowance in this recall is different than that currently published in the labor time guide for performing the same operation. In the near future, the labor time guide will be updated with this new information.


Install a new service engine using the procedure outlined in the appropriate Service Manual.


Important
Refer to GM Service Information Bulletin 02-06-01-031 for 4.2L Goodwrench engine service.


Claim Information
For vehicles repaired under the terms of this special policy, submit a claim with the information indicated below:

Repair Performed
Part Count
Part No.
Parts Allow
CC-FC
Labor Op
Labor Hours
Net Item

Replace Engine with Goodwrench Service Engine
--
--
*
MK-95
T5581

**

2WD





10.7


4WD/AWD





13.4


w/gas tank skid shield





Add: 0.4


w/transfer case skid shield





Add: 0.2


w/AC





Add: 0.8


Reimbursement For Previous Repairs (Canadian Dealers ONLY)
NA
NA
NA
MK-95
T5582
0.2

Administrative labor hours
***

* -- The "Parts Allowance" should be the sum total of the current GMSPO Dealer Net price plus applicable Mark-Up or Landed Cost Mark-up (for IPC) for parts needed to complete the repair.

** -- The amount identified in the "Net Item" column should represent the sum total of the Current GMSPO Dealer Net Price plus applicable Mark-Up or Landed Cost Mark-Up (for IPC) for motor oil and miscellaneous supplies needed to perform the required repairs.

*** -- (Canadian Dealers ONLY) The amount identified in the "Net Item" column should represent the customer reimbursement amount.


Customer Reimbursement - For US
All customer requests for reimbursement for previous repairs for the special policy condition will be handled by the Customer Assistance Center, not by dealers.

A General Motors Special Policy Customer Reimbursement Procedure Form is included with the customer letter.


Important
Refer to the GM Service Policies and Procedures Manual, section 6.1.12 for specific procedures regarding customer reimbursement and the form.


Customer Reimbursement - For Canada
Customer requests for reimbursement of previously paid repairs for cylinder bore liner engine replacement are to be submitted prior to or by June 30, 2004. Repairs must have occurred within the seven (7) years of the date the vehicle was originally placed in service, or 160,000 km (100,000 miles), whichever occurs first.

When a customer requests reimbursement, they must provide the following:

Proof of ownership at time of repair.
The original paid receipt confirming the amount of unreimbursed repair expense(s) (including Service Contract deductibles), a description of the repair, and the person or entity performing the repair.
If the work was done by someone other than a GM dealership, the amount of reimbursement will be limited to the amount that the repair would have cost GM to have it completed by a GM dealership.

June, 2003
Dear General Motors Customer:

As the owner of a 2002 Chevrolet TrailBlazer, GMC Envoy or Oldsmobile Bravada, your satisfaction with our product is very important to us. Your vehicle was provided with a new vehicle warranty, which covers certain parts of your vehicle for a specified period. These warranties are of considerable value to you if you should experience problems with your vehicle.

This letter is intended to make you aware that some 2002 model year Chevrolet TrailBlazer, GMC Envoy and Oldsmobile Bravada model vehicles may experience a cracking of an engine cylinder bore liner. This will cause engine noise, poor performance, and/or stalls with no engine re-start.

This is not a recall. Do not take your vehicle to your General Motors dealer as a result of this letter unless you believe that your vehicle has the condition as described above.

What We Have Done
To address the above mentioned condition, General Motors is providing owners with special warranty coverage. If this condition occurs on your 2002 Chevrolet TrailBlazer, GMC Envoy or Oldsmobile Bravada within seven (7) years of the date your vehicle was originally placed in service or 100,000 miles (160,000 km), whichever occurs first, the condition will be repaired for you at no charge .

What You Should Do
Repairs and adjustments qualifying under this special coverage must be performed by a General Motors dealer. You may want to call the service department at your dealer to find out how long they will need to have your vehicle so that you may schedule the appointment at a time that is a convenient time for you. This will also allow your dealer to order parts if they are not already in stock. Keep this letter with your other important glovebox literature for future reference.

Reimbursement
The enclosed form explains what reimbursement is available and how to request reimbursement if you have paid for repairs for the special policy condition. Reimbursement requests are to be submitted by June 30, 2004.

If you have any questions or need any assistance, must contact your dealer or the appropriate Customer Assistance Center at the number listed below:

Division
Number
Deaf, Hearing Impaired, or Speech Impaired*

Chevrolet
1-800-222-1020
1-800-833-2438

GMC
1-800-462-8782
1-800-462-8583

Oldsmobile
1-800-442-6537
1-800-833-6537

Puerto Rico - English
1-800-496-9992


Puerto Rico - Español
1-800-496-9993


Virgin Islands
1-800-496-9994


* Utilizes Telecommunication Devices for the Deaf/Text Telephones (TDD/TTY)


We are sorry for any inconvenience you may experience; however we have taken this action in the interest of your continued satisfaction with our products.

General Motors Corporation




GENERAL MOTORS SPECIAL POLICY CUSTOMER REIMBURSEMENT PROCEDURE
If you have paid to have this special policy condition corrected before June 27, 2003, you may be eligible to receive reimbursement.

Requests for reimbursement may include parts, labor, fees and taxes. Reimbursement may be limited to the amount the repair would have cost if completed by an authorized General Motors dealer.

Your claim will be acted upon within 60 days of receipt.

If your claim is:

Approved, you will receive a check from General Motors.
Denied, you will receive a letter from General Motors with the reason(s) for the denial, or
Incomplete, you will receive a letter from General Motors identifying the documentation that is needed to complete the claim and offered the opportunity to resubmit the claim when the missing documentation is available.
Please follow the instructions on the Claim Form provided on the reverse side to file a claim for reimbursement. If you have questions about this reimbursement procedure, please call the toll-free telephone number provided at the bottom of the form. If you need assistance with any other concern, please contact the GMC Customer Assistance Center at 1-866-996-9463. The deaf, hearing impaired, or speech impaired should call 1-800-462-8583 (Utilizes Telecommunication Devices for the Deaf/Text Telephones, TDD/TTY).

GENERAL MOTORS SPECIAL POLICY CUSTOMER REIMBURSEMENT CLAIM FORM
THIS SECTION TO BE COMPLETED BY CLAIMANT

Date Claim Submitted:



Vehicle Identification Number (VIN):



Mileage at Time of Repair:



Date of Repair:



Claimant Name (please print):



Street Address or PO Box Number:



City, State, ZIP Code:



Daytime Telephone Number (include Area Code):



Evening Telephone Number (include Area Code):



Amount of Reimbursement Requested: $





THE FOLLOWING DOCUMENTATION MUST ACCOMPANY THIS CLAIM FORM

Original or clear copy of all receipts, invoices and/or repair orders that show:

The name and address of the person who paid for the repair.
The Vehicle Identification Number (VIN) of the vehicle that was repaired.
What problem occurred, what repair was done, when it was done and who did it.
The total cost of the repair expense that is being claimed.
Payment for the repair in question and the date of payment. (copy of front and back of cancelled check, or copy or credit card receipt.)
My signature to this document attests that all attached documents are genuine and I request reimbursement for the expense I incurred for the repair covered by this special policy.

Claimant's Signature:




Please mail this claim form and the required documents to:


General Motors Corporation

P.O. Box 33170

Detroit, MI 48232-5170

All recall reimbursement questions should be directed to the following number: 1-800-204-0261.





GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.
 
#14 · (Edited)
Rebuild Questions/Reliability

ZR WON,

Thanks for the info on the liner cracking. I have been looking for a low km 02-03 TB LTZ or Envoy SLT and have come across an 02 LTZ that I am/was intersted in. Supposedly it has had some bottom end engine work done on it, still waiting for the actual papers to verify what was done. Sounds like it had the piston slap and was fixed.

I guess what I'm questioning is the reliability of the rebuild. Is the piston slap going to occur again, or is the rebuild a guaranteed fix? All speculation of course.

I noticed the parts list states QTY: 1 Engine, Goodwrench Service Replacement. Followed by instructions to install new service engine. Are they doing a short block replacment?

I checked the VIN number and it fits right into the affected number and the in-service date was August 20, 2001. So it was one of the first produced. I'm beginning to think that I will move on and leave this LTZ alone.


Any other advice or information?
 
#15 ·
Deuce said:
ZR WON,

Thanks for the info on the liner cracking. I have been looking for a low km 02-03 TB LTZ or Envoy SLT and have come across an 02 LTZ that I am/was intersted in. Supposedly it has had some bottom end engine work done on it, still waiting for the actual papers to verify what was done. Sounds like it had the piston slap and was fixed.

I guess what I'm questioning is the reliability of the rebuild. Is the piston slap going to occur again, or is the rebuild a guaranteed fix? All speculation of course.

I noticed the parts list states QTY: 1 Engine, Goodwrench Service Replacement. Followed by instructions to install new service engine. Are they doing a short block replacment?

I checked the VIN number and it fits right into the affected number and the in-service date was August 20, 2001. So it was one of the first produced. I'm beginning to think that I will move on and leave this LTZ alone.


Any other advice or information?
If it were me i would try to find one from a different year. If you do decide on that truck make sure it has a warranty(maybe buy an extended one also).
 
#16 ·
Well I had to leave my Tb at the dealer lastnight (scary), and this morning when I went in I had the serive manager listen to the knocking, and he ACTUALLY heard it... WOO HOO!!!!

He said there is definately piston noise, and also possible some with the exhaust manifold gasget... The GM DSM will be in next week to have a look at it, and to tell me what they will be doing with it...

I will keep everyone updated...

Russ
 
#17 ·
Engine Knock!!

Well the District Manger is finally out, and my TB is just sitting there waiting for him to arrive.. Now I hope that he hears the same Knock that Myself and the Service Manager heard...

I will keep you posted, as to what the actaul problem is...

Russ
 
#18 · (Edited)
Engine taps

Hello, Is anyone experiencing the engine tapping/light knock (lifters tapping)when you first startup in the mornings. This noise last any where from 5 to 10 mins. I usually allow vehicle to warmup a few minutes and then start driving and this tapping as you drive off continues and almost has the sound of a faint diesel sound. once car is totally hot you don't here it the rest of the day. Took car in to dealer and they claim its normal. Oh, forgot to mention this is a I-6
 
#19 ·
I would try a higher grade gas and siee if it happens.
 
#21 ·
My '02 does that exact thing. My neighbor, a chevy dealer mechanic, said to put synthetic oil in it. I put regular oil with Lucas stabilizer and it still does it. The '02 engines are known to knock a bit. In looking at the dealer printout, my TB has had at least one cylinder sleaved or replaced. There is a little known 100k mile warranty on mine I think. I hope if it grenades it does it soon. :x
 
#22 ·
Mine does the same thing. The higher octane does nothing to stop it as it's not engine knock. I've just switched over to full synthetic oil last week but I haven't been trying to listen for it. I'm about to head out I'll see if it's still tapping.
 
#23 ·
My 02 seems to luck out every time. :D I havent had any problems except for a rotten egg smell that I think is the catalytic converter?

But, I agree with zamar, if or when my engine decides to go, that it does it before 100k or 2009 when the 7yr 100k engine warrenty is up. The sleeve cracking is a common problem, and I have never had any issues. I havent even had a knock ever, and I drive it pretty hard once I get up my initial hill and the engine warms up.
 
#26 ·
Ok, I checked when I started it up and I couldn't hear the tap. I think the synthetic did the trick. Don't know if it's a problem or just an annoyance. I'll keep listening for it just in case this was a one time fluke.
 
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