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gmlemonowner1gmlemonowner1 Member Posts: 1
My 2001 truck was built with a 1999 engine that had been marked in a TSB for exchange. GM engines display a cold start knock located in the crankshaft main bearings. The knocking pounds the bearings to death. Eventually the engine will fail. GM is telling the dealers to tell the customer that this knocking is normal and that they built it into the engine([non-permissible content removed]). You can do an engine oil analysis on any knocking engine and it will show heavy wear(failure).


  • ryanbabryanbab Member Posts: 7,240
    Ok i dont deny the "knock" shoot i have it at times (not all the time)

    But how do you know your 01 was built with a 99 engine?

    TSB for an exchange?

    When does the failure occur? I know a few people with 99's whos knocks and they have 80-100K miles and no problems. No performance losses.

    Did you do an oil anaylsis? What were the results? (Actual) what was found in your oil?

  • ricschricsch Member Posts: 540
    I have read where guys have put on quite a few miles, with engine knock and no trouble. Not to say it couldn't happen. This "problem" is being talked about on many forums and there are many thoughts of the cause, and the worst thing is that there doesn't seem to be a definate cure as of yet. I've been told by a GM service manager that they were instructed to replace engines in a few trucks with the knocking, and the new engines were worse. I currently only have 4200 miles on my '01 Silverado and haven't experienced the noise so far, but if it rears it's ugly head, I'll be the first to contact GM and the BBB. Curious to hear about the oil analysis.
  • jaguar0027jaguar0027 Member Posts: 387
    Ditto and well said my man!

  • kyarcherkyarcher Member Posts: 12
    I have a 98' 5.7 that knocks for about 5-10 seconds at first start. Started about 5,000 miles and now has 70,000 with no problems at all. I was told by a service rep that this was "spark knock".
  • michgndrmichgndr Member Posts: 160
    Methinks it was a Tindy owner trying to raise a ruckus...
  • roger350roger350 Member Posts: 157
    I just got my first oil analysis back at about 12000 miles, and it listed copper levels as critical. If my memory serves me right, copper is the top material on the tri-metal bearings used for the crank? So I am very concerned. I am hoping GM will do a short block replacement on these engines. But rumor is it will be new pistons only. I am sick to my stomach about this whole deal, as I really planned on keeping this truck for the long haul. But if GM screws us around I'll be trading for a Ford SD with the next generation Powerstroke next year.
  • obyoneobyone Member Posts: 7,841
  • ryanbabryanbab Member Posts: 7,240

    (i think the link will work)

    I have a kit coming in the mail soon

  • roger350roger350 Member Posts: 157
    I used a kit I bought at:


    They were recomended by a couple guys over on the dieselpage.
  • edetoredetor Member Posts: 12
    I have a 00' 5.3 w/ 21k miles. The knock has been around since 3500 miles on cold starts. Dealer agreed to replace with a new engine which was just completed. Hope it works, repair order stated new pistons will not be ready until january 02' therefore gm agreed to replace entire engine.
  • ricschricsch Member Posts: 540
    keep us posted as to if the new engine develops the knocking. Thanks
  • milkhaulermilkhauler Member Posts: 1
    We have an engine knock in our 2000 Silverado, engine is a 5.3. Chevy said they would
    replace the engine but the pistons will not be out until first or second quarter of 2002.
    They stated it will not be on a recall bases, but as a complaint bases. They said the pistons have 3000th gap... therefore wouldn't piston slap cause leak down in the cylinders? Of course!
    The engine integrety has been compromised and were stuck with Chevys BS lines! NOT!
    We DO HAVE IT IN WRITTING WHAT GM TOLD DEALERS WHAT TO SAY- THAT THE KNOCKING IS NORMAL. As I said, if it was normal - WHY are they so willing to drop an engine in... but what is the advantage if the pistons are the same and not the teflon coated ones. Chevy knows its a problem and were the idiots stuck w/ them until we jump the boarder and buy another brand! God Bless Us ALL!
  • rayt2rayt2 Member Posts: 1,208
    then scan it and post for all to see so it can be copied and used by those in need of combating the GM......BS

    Ray T.
  • whatsachevywhatsachevy Member Posts: 136
    I have an '01 Chevy 2500HD LS EC SB 4X4 6.0/4.10 Auto. I now have a little over 7,500 miles on the truck. Just changed oil for the third time and rotated the tires. I have not had a single problem with this truck so far. No shudder/vibration, no hesitation, no knocking, just pure Chevy power (and I'm an old Ford guy). I do not use synthetic oil and have driven the truck pretty hard from day 1. I have averaged 13.2 mpg for the life of the truck (delivered 4/19/01). Hopefully, this will continue for several hundred thousand more miles. My previous two trucks were Ford 1/2 tons (both trucks had well over 200,000 miles on them when sold). Test drove the Ford 3/4 ton and the Chevy 3/4 ton. There was no comparison. I have installed a LINE-X bedliner (definitely recommend this liner to anyone). I plan on putting 16"x8" wheels and 285/75/16 mudders on as soon as I can convince the wife that it really does need new tires/wheels. My only complaints with this truck is the placement of the oil drain plug (empties all over the left side crossover pipe) and the 100 mph limiter (mine actually shuts down at about 97 mph). I did pick up a good trick from townhall for changing the oil. I tape a piece of aluminum foil over the crossover pipe - works great! I also picked up a pretty good trick from a buddy of mine so you don't make a big mess changing the oil filter (which is also an GM engineering snafu on placement). I poke a hole in the bottom of the filter with an ice pick (make sure you buy your own and don't use the one from the kitchen) and let the oil drain out before removing - this also works great! This is my first truck with an automatic transmission and may be the last. The automatic just can't figure out which gear my foot wants to be in - didn't have that problem with a stick. But, it is nice for backing the boat into the garage. Sorry for being so long-winded. God Bless to all!!!
  • obyoneobyone Member Posts: 7,841
    Way too funny,......nuff said.
  • seeligseelig Member Posts: 590
  • eric2001eric2001 Member Posts: 482
    taken a few out? Or they were removed by the author...
  • seeligseelig Member Posts: 590
    at first i thought the original post (you know, the one where post 1 says "BS" in full length) but then i figured an arguement broke out.....
  • obyoneobyone Member Posts: 7,841
    ....with no eggs. A troll with nothing else better to do.
  • y2kgmcy2kgmc Member Posts: 23
    I have a 2000 gmc sierra 4.8 which sounds like a diesel at idle , dealer first said it was because i was using too high an octane fuel and it was carbon buildup in the cylinders, and to switch to regular fuel and it might go away and if it didn't they would keep it overnight and soak it with a solvent to dissolve the carbon .well it didn't go away . a friend who happens to be a field service engineer with Saturn listened to it and said it was definately piston slap..
  • seeligseelig Member Posts: 590
    they all do that.....LOL....betcha heard that one already.
    do like a lot of us have done and file with the BBB. it resulted in an extended warranty (courtesy of GM) for quite a few who have this problem.
  • minikinminikin Member Posts: 389
    an octane fuel producing carbon build-up on a new engine!! Thought after all my years as a wrench I'd heard everything. Never under estimate stupid!
    -- Don
  • obyoneobyone Member Posts: 7,841
    to become Service Manager.....we already know its one to become a tech......stupid that is.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Info - Engine Knock on Cold Start #01-06-01-022
    Information on Engine Knock on Cold Start
    2001-2002 Chevrolet and GMC C/K Pickup and Utility Models

    with 6.0L Engine (VIN U -- RPO LQ4)

    Some of the above vehicles may exhibit an engine knock noise that begins in the first several thousand miles/kilometers of use. The knock noise is most often noticed during initial start-up and typically disappears as the engine warms up. The noise is usually more noticeable on the initial start-up when the temperature is below 10°C (50°F) or if the vehicle has not been used for several days.

    This noise may be caused by an interaction between the piston and the cylinder wall. GM Powertrain Engineering, and an analysis of engines returned with this condition, has confirmed that the noise is not detrimental to the performance, reliability or durability of the engine. The noise does not have any effect on the longevity of any of the engine components.

    At this time, replacing the engine assembly or pistons will not eliminate this noise.

    Please share the information found in this bulletin with customers who inquire about this condition. In the event they have additional questions or concerns, please advise them to contact Customer Assistance at the numbers listed below for further information.

    Deaf, Hearing Impaired, or Speech Impaired*


    8a.m. - 11p.m. (EST)

    8a.m. - 11p.m. (EST)


    8a.m. - 11p.m. (EST)

    8a.m. - 11p.m. (EST)





    7:30a.m. - 11:30p.m. (EST) (Mon-Fri)

    7:30a.m. - 6p.m. (EST) (Sat)

    7:30a.m. - 11:30p.m. (EST) (Mon-Fri)

    7:30a.m. - 6p.m. (EST) (Sat)

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

    © Copyright General Motors Corporation. All Rights Reserved.
  • ricschricsch Member Posts: 540
    so now that the temps will be under 50 for another 3-4 months, I'll notice the "knock" in my 5.3, that's great!@##@ Can hardly wait to see the service? department, and their "Cannot duplicate" excuses.
  • ryanbabryanbab Member Posts: 7,240
    seems that mine is quieter in colder temps (5.3)

    it has been dipping below 50 quiet often here lately also. Supposed to snow by the end of the week
  • jasonpeterclarjasonpeterclar Member Posts: 30
    My 5.3 raps a bit on startup/no-load conditions. The funny thing is, my old Blazer did too. The 4.3L V6 had a nice rap, especially when cold. Now that it has 170,000 miles on the original motor, with good compression and power, I don't worry about the piston/head problem.

    I do notice that the sound is a little different...but I think that is because the Blazer had iron heads and the 'rado has aluminum heads. They make different sounds when you slap an aluminum piston into them.

    I'm sure its a GM powertrain, piston clearance spec that is a little tighter than most. For emmissions no doubt. I've heard the small V-6 (2.8, 3.1, 3.4L) derivitives and the Buick V-6 make the same noise. Once the engine starts to warm up, the cylinder length grows a few mils, and the contact goes away.
  • txyank1txyank1 Member Posts: 1,010
    I was under the impression that was just 6.0.
  • winkelwinkel Member Posts: 2
    As some of you might know, all metals expand and contract with hot and cold. GM is the #1 motor manufacturer in the world, and their motor boast more horsepower and torque than any other motor company in the world. To get the most out of their motors, they have to make the most out of the room they have to work with. there is only a 1000th of an inch in between the piston and the cylinder heads. Thus, when it is cold, the piston expands to fill up that 1000th of an inch, but when it warms up, the slap goes away. This problem is very rare. I work for a GM dealership in Reno Nevada, and have driven thousands of trucks and never heard any piston slap before. This is why GM isn't recalling any of their motors. there is a margin for error, not every piece that comes out of the mold is exactly the same. This is no excuse, but GM does back their products 100%. If you are dealing with a service department that is making poor excuses for GM, then you need to find a new service department or contact GM direct. Keep in mind, that the Service departments of GM dealerships are independently run. Although most of the service writers that work for the GM dealerships have had some sort of training, some have not. They are people too, and people make mistakes (and excuses). For all of you people that bought a GM truck and are thinking about going to another make, feel free. I don't mind all of the Fords and Dodges out on the road as long as they keep their under powered trucks out of my way. But don't let your local dealerships service department steer you the wrong way. There is way too many resources available on the net now days, so ask you questions to the right people. Good luck to all the people with problems, and remember that when you are #1, there will always be someone trying to drag you down...

    Nick Vanderville
    Internet Manager
    Winkel Pontiac GMC Hummer
    -Reno, Nevada-
  • musky1gfmmusky1gfm Member Posts: 36
    I have a 2001 5.3 gmc 1500,noise developed at 7000 miles.GMC csr service said there will be a recall,4th quarter this year.Or 1st quarter 2002.Pistons will be replaced.Same line about no damage to engine currently,that's hard to believe.
  • sfishsfish Member Posts: 27
    you mentioned filing with the BBB. How do you go about doing that? My 2001 5.3 has about 60 seconds of diesel loud knock on all start up, not just in the morning. I rebuilt a ford 1966 flat six one time because of the same noise and it came back in a couple of weeks. Engine ran fine for ever. My 'rado has a ping that only occcurs when outside temp is more than 70 F. I am really more concerned about that, but my 92 Explorer developed a ping at 17k and I did everything spent hours and days with the dealers (multiple) and never did fix it. Still going strong at 163K.
    Thanks for the help
  • seeligseelig Member Posts: 590
    i took the truck to the dealer for them to verify what i was hearing on cold start up. then placed a call to BBB, which in turn called whomever it was they talk to at GM. then the GM rep contacted the dealers service manager. the SM then confirms my concern, and then, the GM rep called me with an offer. then, i agreed to a 5/100K warranty which GM gave me free of cost. i'm not 100% sure on this, but i do believe that the SM has to back your concerns up, or you won't see any offer from GM. if they did, (without out verification) everybody would be driving a rado with 5/100K warranties.
  • frey44frey44 Member Posts: 230
    If you understand the phenomenon of piston slap (many engines do this), why such a big worry ? Other than noise, very lttle damage can result from this. I have a NISSAN motor (2.4 liter 4 banger) that is famous for this: It currently has 168 000 miles on it with virtually no major troulbes. As soon as it warms up, the noise goes away. You guys have little faith in GM motors> they are still the best V-8's out there, IMHO, with maybe the exception of the Toyota alloy V-8.
    The Chevy motors will run forever. Just feed 'em clean oil and let em slap. They will slap for 250 000 miles without an overhaul.
  • fortopfortop Member Posts: 239
    So far (about 1500 miles) not a hint of engine knock, rough idle, or other engine quirks. This engine approaches Japanese smoothness - which is something for an engine twice the size of the average Japanese engine.
    I did drive an identical 2001 Yukon 5.3 (non-ethanol capable engine) about a year ago and the engine vibrated so bad you could see the steering wheel shake at idle - even with the transmission in Park.
    Does anybody know what the difference is between the new ethanol capable 5.3 and the non-ethanol capable vehicle? Maybe more hardened valve seats? Should I invest in corn futures? ;0)
  • markbuckmarkbuck Member Posts: 1,021
    1. The pistons do not hit the head. This would be catastrophic... The squish clearance on the head is at least .020" if not more....
    2. All the newer LS1 engines have aluminum heads. The 4.8L and 5.3L have had them from the start. The 6.0L got em in 2001.
    3. The knock you are hearing is most likely either:
    a)piston slap, that's where the piston rocks back and forth on the end of the rod, and the piston skirt taps against the cylinder till it warms up.
    b) lifter tap, where the hydraulic lifter is pumping up to take up the clearance between the valve and the rocker arm.
    c) maybe light rod knock in the bottom end, where the big end rod bearing clearance is a tad large, GM supposedly tightened this clearance up for 2001.
    d) maybe ping, I got this under load on 87 octane on both my 4.8L and my 6.0L. 91 octane would alleviate it
    e) manual transfer case shift linkage rattle. Both my 4.8L and my 6.0L did/does it. Just gotta put a little washer on the linkage ball joint.
  • newbamanewbama Member Posts: 11
    Have 15,000 miles and after 5,000 it started with
    the cold knock. Having read all the posts, I took
    it in for a oil change at the Chev dealer and had
    him listen to it. He told me that GM was only going to change the pistons for the 4.8 and 5.3L.
    I called GM and started a file and they quoted the
    GM standard of "its not a problem". I,m now waiting on the Service manager to get with the
    District rep and get his comments.

    My plan is to go the BBB route just to be on the
    safe side if I get no recourse from the Rep.
  • roger350roger350 Member Posts: 157
    Like Markbuck said, if the piston was slapping the head, it would be a major problem!

    And to Nick in Reno, water is the only thing that expands when it's cold, everything else contracts when cold, and expands when hot.
  • joe3891joe3891 Member Posts: 759
    Markbuck glad to see you straightened the knock problem out,i always thought it was piston slap myself,that will go on for years with no problems.
  • kanton1kanton1 Member Posts: 41
    has anybody had knocking with the 8.1? seems like most of the knocking is with the 5.3 and the 6.0. My 2000 5.3 knocked about 5 times total. I sold it with 32,000 miles on it. never a problem with the motor.
  • jlflemmonsjlflemmons Member Posts: 2,242
    I have the piston slap also. Sometimes loud, other times can't even hear it. The engine runs smooth as glass, uses less than 1/4 quart of oil between changes, and starts EVERY TIME on the first compression stroke. I figure if there is something all that bad in the engine it will show up before 36K. If the knock/slap gets worse, I will bring it up with the dealer. For now, I will just drive and enjoy my truck.
  • markonemarkone Member Posts: 3
    I took my 2000 Silverado in for the 5.3 engine knock yesterday. The service writer I had said that they have been getting alot of these lately.

    They are fully aware of this problem but try to say it's normal. I showed him this page from this brochure http://agmlemon.freeservers.com/2001_Engine.htm

    The service manager said that it di NOT come from GM. Does anyone have a link to the entire brochure? I think if I have that it will change their minds.

    I also said something about the pinging and rough idle. He showed me a bulletin on the pinging from GM that of course, says it's normal. Yeah right.

    Had them check the ABS brakes. If I am stopping somewhere and there are bumps in the road, it triggers the ABS and I end up stopping farther then I wanted, like in the middle of a intersection. Was told there would maybe a new software update soon. Sounds like more BS to me.

  • ryanbabryanbab Member Posts: 7,240
    i found larger tires to help with the abs not engaging as much. (i reprogrammed for the larger tires also)
  • txyank1txyank1 Member Posts: 1,010
    have gotten better on the '01's. I don't notice it like I did on my '99.
  • modvptnlmodvptnl Member Posts: 1,352
    You sound like a used snake oil.....er car salesman. I've NEVER seen so much mis-info in one post. I feel for your customers.
  • seeligseelig Member Posts: 590
    i just went back and read that post by Mr. Winky, and i must say that is the best laugh i've had in awhile here. "pistons expand when they are cold?"
    then engines don't need rings then eh?
  • tiredofwaitingtiredofwaiting Member Posts: 74
    Here is a link to a GM archive that holds the 2001 engine bearing tolerance announcment. Tell your service manager it is from the GM Media site.


  • rich32rich32 Member Posts: 9
    My 2001 5.3 makes a ticking noise when it first starts cold. I get the impression most of you are getting something that sounds far worse than what my engine does. Is that true?
  • chevytruck_fanchevytruck_fan Member Posts: 432
    As far as I can tell everyone that has a problem with piston slap really has a lot of BS from people at dealers that don't know what they are talking about.

    How does anyone know it is a problem? Many engines have this, the toyota 4.7 has been known to do this (I seen posts on the toyota posts saying they hear a sound like this), it is really not out of the ordinary.

    I would say were not going to know either way till these trucks are much older. But I have not heard of anybody with high oil consumption which would be what would result if this was a true problem.
  • obyoneobyone Member Posts: 7,841
    They had the piston slap and replaced a whole bunch of motors. Rather than wait for long term problems, I would take oil samples. Cause $20 is cheap for peace of mind.
This discussion has been closed.