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GM ENGINE KNOCK

1356717

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    plutoniousplutonious Member Posts: 799
    Uhm, playdough's problem IS the drivetrain, EINSTEIN! Toyota offers the 5/60K on the drivetrain, as you stated.

    So, a longer drivetrain warranty (GMC's is only 3/36K), like Toyota's, certainly would have been of help for playdough.

    obyone, you are as sharp as a razor!
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    plutoniousplutonious Member Posts: 799
    I would still like you to answer my question. If Chevys are "the most dependable, longest lasting trucks on the road" why does playdough need the extended warranty?

    My guess would be: He isn't confident it will go 60K or 100K miles without major repairs because of that knocking engine!

    What's YOUR answer?
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    seeligseelig Member Posts: 590
    scroll baack 30-40 posts and you will see what some of us have done to get a 5/100K full waranty.

    -
    you will have to wade through the Pluto/Bama garbage though......sorry, it seems we hvae children posting in here at times.

    b
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    plutoniousplutonious Member Posts: 799
    mention the obyone garbage too.
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    seeligseelig Member Posts: 590
    Good luck on that one too!!
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    plutoniousplutonious Member Posts: 799
    my warranty to fix anything. The head gasket problem was solved years ago before I bought my truck.

    See, Toyota actually learns from the few mistakes it has made, like the head gaskets, and fixes the problem.

    But GMC just continues to crank out engines that knock, then fights people tooth and nail when they want the problem fixed. GMC CAN'T fix it, that's why they're offering extended warranties.

    At any rate, who wants to spend $30K on a truck whose engine knocks, even if GMC decides to extend your warranty?

    If I wanted an engine that knocks, I'd buy a diesel for crying out loud, and get the longer warranty that diesels come with in the first place, LOL!

    Have fun with THAT one, now!!!
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    bamatundrabamatundra Member Posts: 1,583
    It is too bad that Ford owners had to suffer through this problem. Many owners had to accept the piston slap because Ford said "It was normal".

    It seems that history is repeating itself. I would suggest that GM Knock owners visit the F10online website and do a search on "Piston Slap". I am sure that GM owners will learn some lessons. Ford terribly mishandled this problem, I would hope that GM would do better!
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    gator36gator36 Member Posts: 294
    a GM engine with the Engine knock go south on them?

    It seems to me that there are alot of people that are complaining
    about the noise and I have yet to hear of a knock related failure.

    I also hear Toy owners trying to make a mountain out of a molehill
    regarding this issue. Basically people that need to get a life.

    Could it be that the Piston Slap is just an Annoyance?

    GM has acknowledged the issue in TSBs
    GM does not have a solution yet. What are they going to tell you?
    The engine is working as it was designed.
    No doubt that GM will come out with a fix soon, and it will be a
    repair for a "Customer annoyance Issue".
    Just keep in mind that any solution to this issue will have to be
    well engineered and that takes time. Time for testing in the field as well
    as Destructive testing.
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    plutoniousplutonious Member Posts: 799
    is you Chevy guys sure have low expectations paying $30K for a truck and aren't bothered at all if the engine knocks, as long as Chevy is willing to extend the warranty.

    Seriously, I think many of you have been brainwashed by obyone, owner of the Chevy in the shop 4+ months who continually brags about his truck.
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    seeligseelig Member Posts: 590
    amazing how you two seem to post within minutes of each other.........maybe one in the same?
    we'll find out.
    at any rate, you two have got to be the most antagonizing poster(s) on this forum. you obviously don't have lives, and this consistent stalking of Obyone, and the way you put up posts and then delete (name calling) has gone way beyond what's known to be abnormal. i know it's better to just ignore immaturity, and you two (or one) certainly aren't taken seriously, but your foolishness is really getting on peoples nerves.
    if you own trucks that are trouble free, then we are all glad for you, but some people i talk to on other forums have gone there because the nonsense you cause here is simply chasing people away from Edmunds. good job........i'm sure that Edmunds is real proud of you.
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    plutoniousplutonious Member Posts: 799
    with you seelig on all this nonsense. But honestly, you are a hypocrite of the highest order by not including the likes of tbunder, obyone, quadrunner500, stang, etc. in your little abmonishment.

    I will refrain from posting in this thead from now on, however, as I can speak from experience how annoying it is when the likes of tbunder, obyone, quadrunner500, stang, etc. keep posting in our Toyota threads.

    There. I am acting like the adult here. Let's see if the likes of tbunder, obyone, quadrunner500, stang, etc. do the same. Doubtful.
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    chevytruck_fanchevytruck_fan Member Posts: 432
    atleast you can start the chevy unlike the tundra with widespread hard starting problems
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    y2kgmcy2kgmc Member Posts: 23
    who's there? / 4.8
    4.8 who? / 4.8 in shop again for engine noise ,once again they tried to tell me it was from too high an octane fuel but told them I switched to low grade fuel last summer on their advice with no change. I also have hard starting condition warm ,starts fine when cold but cranks for a while after engine is warm. Ed
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    gator36gator36 Member Posts: 294
    My old 97 GMC had the piston slap. I sold it at 150,000 miles. No oil burning
    Nothing. The truck was in excellent shape inside and out. It unfortunately
    was a 2wd and I wanted 4wd. So I upgraded. 2001 Chevy Silverado. No knock.
    I will say this. There is no substitute for a good dealer and an excellent
    service writer. Too many of the service writers out there are boneheads.
    They don't know s*** and they guess when they don't know the answer.
    I am lucky to know serveral in the business that are former mechanics.
    These are the ones that know what they are doing. They know who to talk to
    to get the answers.
    In any case I would rather deal with a Bonehead Chevy service writer than the
    many arrogant take it or leave it Toyota Service writers. My wife having owned a Toyota
    passenger car in the past, I had first hand experience with the idiots in several Toyota
    service departments.
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    minikinminikin Member Posts: 389
    If anyone tries to tell you your problem is related to burning a too high octane fuel, go somewhere else; anywhere else, even if it's to your local hair dresser!
    -- Don
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    gator36gator36 Member Posts: 294
    Looks like the specially coated pistons
    are going to be a reality. Just got off
    of a conference call with a local service manager
    and the regional field engineer.

    GM has produced 500 sets of these specially coated
    pistons and installed them in field tests.
    In every case these pistons have solved the problem.
    The pistons are made by a third party, that due
    to the production requirements, had to build a new
    production facility. This new facility is
    scheduled to open first quarter next year.

    When I asked if there had been any issues of
    longevity with the current pistons, the reply
    was "none reported."
    Some dealers have replaced motors for complaining
    customers only to have the piston slap come back.
    Now these dealers are having to eat the cost of the
    motor as well as deal with a possible buy back
    based upon the lemon law. As I was told, GM has
    tied the dealers hands regarding this issue only
    to tell them that a fix is in progress.
    As I also understand, this will not be a recall
    as it does not affect longevity of the motor. It
    will be based upon customer complaint.
    GM went with the current design in order to
    help their CAFE requirements. Less drag from the
    piston skirt equals better fuel mileage. What
    they did not count on was the consumer backlash
    from the resulting piston slap.
    They also asked me which brand of gas I was
    using. Apparently Chevron gas is the best for
    the 5.3 l motor. A certain gas suppliers product
    has produced alot of carbon build up on the pistons
    and valves.

    Who knows what we will see.

    Take it for what it is worth.
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    ricschricsch Member Posts: 540
    How much difference in fuel economy could there be with the current pistons versus the new, coated type? Wouldn't it be easier for GM to give owners with the problem an extended warranty, than to have someone replace the pistons? I would think if it actually isn't supposed to be a reliability issue, I'd go for the warranty rather than have somebody under the hood of my truck and possibly creating other problems.
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    gator36gator36 Member Posts: 294
    As I understand GM has only given out the Extended warranty to appease the consumers
    who are threatening with a Buy Back. It is a tough decision, Live with the Piston slap
    or let some engine tech go through it?
    The new pistons were not designed for mileage but to reduce the piston slap without affecting
    the current mileage. Only time will tell.
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    rayt2rayt2 Member Posts: 1,208
    Have you read this article, Quad posted on another board but it is directly related to "engine knock" even though it is on the Corvettes. Their engineers also say to avoid engine replacement.

    http://www.c5registry.com./2k2z06/page5.htm


    Ray T.

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    gator36gator36 Member Posts: 294
    I had read the article. It sounds as though the
    Truck 5.3 Vortec is going the same route.
    The only engine replacement I would suggest is one that already has the new pistons in it.

    Walter
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    trashman1trashman1 Member Posts: 1
    I too was experiencing the engine knock in my 2000 Silverado. I tried a couple of different brands of oil and finally setteled on Valvoline full synthetic with a K&N oil filter. that was 2 months ago and haven't heard a knock since.
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    bobmillerbobmiller Member Posts: 2
    My 2001 GMC Sierra (4.8L) has the horrible loud knocking sound - 23000 miles on it.
    It sounds like a bad lifter or something - is it really piston slap? very annoying.
    dealer runs fuel injector cleaner for it, comes up with all kinds of excuses.
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    gator36gator36 Member Posts: 294
    I would suggest finding a more competent dealer.
    If it is as loud as you state, there must be something wrong.
    To some of us it is extremely loud yet others may never hear the
    same sound from the same engine. Try to compare it to a like
    vehicle.
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    ricschricsch Member Posts: 540
    Have any of you noticed the knocking noise (piston slap or whatever) when the engine was still warm? I notice the noise on cold starts almost regularly, and the same noise is present as in today I went to a store and came back out approx. 1/2 hour later, hit the remote start, and again heard the noise. Temp gauge read about 190 or so, outside temp. around 25-30 degrees. I only have 6000 miles on the truck, and plan on keeping it for quite some time, yet as I have stated before, I dread having GM open up the engine, possibly creating more trouble.
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    ndahi12ndahi12 Member Posts: 235
    If the knock ONLY happens for 10-20 seconds on start up in the morning when the engine is cold, then that is perfectly normal.

    Cold engines have oil at the bottom of the pan and until the oil runs through the engine, then you will hear clatter and noise.

    You have a problem if the engine is warm and you get knock or you get knock under load.

    From what I understand, that is what you have.
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    obyoneobyone Member Posts: 7,841
    the problem lies with "some do it and some don't". If you have one that does, it becomes a problem. For those that don't, well, until your's does you don't really know now do you.
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    teptep Member Posts: 10
    I own a 2001 Sierra Z71 5.3 with cold engine start-up knock since early on. After reading about it on this site and others, I chose to try my best to ignore it and suppress mental images of metal shavings and bearings swirling around in my oilpan. Recently (6K miles) did second oil change with switch from dino to Mobil 1 5W-30, Purolator Pure One filter. The knock now seems a little louder, and I also hear a "clatter" at low rpm, especially under some load. Coincidence? Can anyone think of why the synthetic oil might have made this worse? The oil pressure is slightly higher with the synthetic and the truck hasn't discernably burned any oil.

    Thanks.
    tep
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    PAmanPAman Member Posts: 207
    When you do your next change, and you stay with a synthetic, consider going back to a 10W30. When warm, the 5W30 oil looks more like iced tea rather than motor oil.

    Manufacturers like 5W30 (or 10W20 in a Ford) because it helps bump up their CAFE (Corporate Average Fuel Economy) numbers a little, which are mandated by law.

    The synthetic oil actually has much better ability to adhere to surfaces for a longer period of time. The Air Force has been using it extensively, especially in engines (gas and turbine) exposed to near-zero and sub-zero climates for years. SAE testing has clearly verifyed the superior coating qualities of synthetic oils.

    Good luck!

    Joe
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    modvptnlmodvptnl Member Posts: 1,352
    Considering the Ford V10 is exempt from CAFE your explanation on 5-20 holds no weight. Get it? No weight.......I kill me!!!
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    PAmanPAman Member Posts: 207
    So.....one engine is exempt from CAFE ratings and you think the 5W30 arguement has no weight? Funny...especially considering that Ford sells about ten F150 trucks and five Rangers that are considered for CAFE ratings for every one-ton chassis with a V10. And, I was talking to him about a GM 5.3L V-8 in a half-ton chassis, which is definitely considered in the CAFE ratings. Why in the world do you think a Ford V10 engine is involved in a discussion about GM trucks??

    Oh, you didn't know that it is the truck's GVWR that determines if it is considered for CAFE ratings, and not the size of the engine? Too bad....guess you were too busy trying to be funny at someone else's expense to bother checking the facts. Wow...you could work for CNN with credentials like that!

    And, oh, by the way, the way to refer to an oil's SAE rating is 5W30, or 5W20, not 5-20.
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    rayt2rayt2 Member Posts: 1,208
    oil viscosity recommendation is for 5w30, why would you suggest "going back to" 10w30 when thats not what is recommended by manufacturer, do you know something we don't.

    You suggested to TEP that "SAE testing has clearly verifyed the superior coating qualities of synthetic oils." Then why would he have a more pronounced "knock & clatter" after this recent switch to the more superior synthetic??

    Curious minds what to know !

    I am not convinced to switch to the more expensive synthetic oils, the only one benefitting from it is stockholders and oil company CEO's.

    Don't mind modvptnl comments, silence is deafening!

    Ray T.
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    modvptnlmodvptnl Member Posts: 1,352
    Who pissed in your Cheerios old man???

    The reason I brought up the V10 was your comment here;

    Manufacturers like 5W30 (or 10W20 in a Ford) because it helps bump up their CAFE (Corporate Average Fuel Economy) numbers a little, which are mandated by law.

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

    Of course I know that CAFE is based on GVW. You can't get the V10 in anything but the 3/4 ton and up chassis. Your sales comment has nothing to do with the V10 and its 5-20 recommendation for CAFE reasons. Understand yet???

    I'll try it a more simple gentle way. Why would 5-20 be recommended for the V10 when it AND THE CHASSIS it's in isn't subject to CAFE???

    BTW, "arguement" is spelled argument.

    Let's get our ducks in order next time before we try correcting other people...

    -------------------------------------------------
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    PAmanPAman Member Posts: 207
    You drive a Toyota???

    And, oh, by the way, it is STILL 5W20, not 5-20.

    And, as I said, I never even brought up the Ford V10; I just made reference to the fact that Ford recommends 5W20 in many of its engines rather than GM's preference of 5W30.

    If you admit that the V10 isn't included in the CAFE calculations, why did you bring it up? I didn't mention the GM truch models also not included in the CAFE.

    The Toyota crying chat room is down the hall and to the left.

    See ya!
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    modvptnlmodvptnl Member Posts: 1,352
    I own the V10. I quoted you where you brought up Ford.

    You said the "REASON" was CAFE for the 5-20. I'm simply asking why Ford would recommend 5-20 in motors that aren't subject to CAFE.

    Guess what? The 5.4 V8 in the Super Duties (3/4 and up) also recommens 5-20. They, also, are not subject to CAFE.

    Is this the twilight zone???

    If the reason for 5-20/5-30 is CAFE as you so eloquently stated in your first post(mentioning Ford I might add) Why do motors not subject to CAFE run it???? I'm trying to let you save face here, instead you keep with the stupid, meaningless corrections and toy comments. I guess that's what people do when they're wrong.

    What is recommended for the 8.1? If it's also 5-30 I think that also shoots your CAFE theory all to heck. Same with the 6.0, does it have different oil recommendations for 1/2 and 3/4 ton? So forget the Ford motors. Does GM have different recommendations for their CAFE exempt vehicles?

    Oh, and BTW, "truch" is spelled trucK. Dohhhhhh.
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    PAmanPAman Member Posts: 207
    Someone who does NOT own a GM truck in here being a baby.

    Whey you go to the parts store, be sure and ask them for 5 DASH 20 oil. When they tell you they only have 5W20 or 5W30, guess you'll have to settle for that.
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    ruddsterruddster Member Posts: 19
    What is it with the inflammatory responses all over this darned board? I have used this board often & have learned a great deal!! What used to be constructive sharing of information, perspectives & experience has degraded into a forum of nit-picking & wise-cracks. If you can't be constructive or use an adult tone, don't post!

    By the way, yes, Chevy does recommend 5W-30 in the 8.1!

    Jeff
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    smith53smith53 Member Posts: 72
    if you know its not cafe ratings then why do they recommend 5w20? there has to be a reason.
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    teptep Member Posts: 10
    That was certainly more controversy than I thought I would stir up with my original post!

    I should have mentioned that I switched to the 5W-30 Mobil 1 from 5W-30 Pennzoil conventional oil (Duraguard filter). I've only changed the oil twice. I'm not sure what the engine ships with, but I suspect it is also conventional 5W-30 oil.

    tep
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    modvptnlmodvptnl Member Posts: 1,352
    I was told by Ford that the oil passages/tolerances were smaller/closer and therefore a higher viscosity wasn't needed. Not sure that's the correct reason either but it's more viable then CAFE.

    What's funny is that Honda also recommends 5-20 and there isn't one car in their line up that gets under the CAFE.

    ruud, I apologize about the rantings. I simply stated a disagreement with a hot head. If the 8.1, which is exempt from CAFE BECAUSE of the GVW, runs 5-30, why would GM state to run a lower viscosity just for fuel economy if it doesn't count against their average?

    PitAman, I actually am quite able to get my own oil off the shelf. Stop being so anal and defensive. Sorry I disagree with you about the CAFE being the reason. From now on, everything you say shall be gospel(even if you spell it wrong) LOL!!!
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    PAmanPAman Member Posts: 207
    OK, Ford brain....I'm done.

    From now on, I will try to offer constructive advice ONLY to those asking for help, and ignore the ramblings and offensive attempts to sound funny at someone else's expense made by non-GM owners here in a GM forum.

    As for my reactions, I apologize only to those looking for assistance here in the forum. I'll not fall into such a silly juvenile trap again in the future.

    TEP: As for the oil shipped from the factory, I was once told by a GM rep that the engines are usually shipped with a slightly heavier oil to aid break-in. The one exception I know of are the Corvette engines shipped with Mobil 1 from the factory.

    Joe
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    midnight_stangmidnight_stang Member Posts: 862
    PA-> I'm still interested to see if you have an explanation on CAFE and Oil weights.
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    mrurlmrurl Member Posts: 116
    Why would GM run 5W30 in their CAFE exempt engines? My guess would be because they buy the oil by the tank truck and don't want to add to the tank farm at the assembly plants. One oil for all vehicles means better price and less storage facility cost.

    Peter
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    PAmanPAman Member Posts: 207
    I think that when GM went from ethylene-glycol based antifreeze to DEX-COOL® , they did it across the board in all of their vehicles.

    They did the same thing with the conversion from R-12 to R-134a refrigerant in their A/C systems.

    When they changed paint from a lacquer to enamel-based paints, they changed out entire factory at the same time so that all models made in that factory were painted with the same type of paint.

    GM has also used many other standardized items, such as the same or virtually the same radios, brake pads, windshields and other non-body items in similar models.
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    rayt2rayt2 Member Posts: 1,208
    which of course is pure GOOD business sense and the stockholders appreciate it too!

    Now, any theory on what I asked the other day, "You suggested to TEP that "SAE testing has clearly verified the superior coating qualities of synthetic oils." Then why would he have a more pronounced "knock & clatter" after this recent switch to the more superior synthetic??"

    I can't figure it since 5w30 is 5w30 whether synthetic or not the viscosity is the same.

    Ray T.
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    modvptnlmodvptnl Member Posts: 1,352
    That's fine and I can live with that but it has nothing to do with CAFE.

    PitAman, sorry my original pun hurt your delicate, sensitive feelings. Ray has now asked twice for your constructive advice. We all await anxiously for your profound wisdom.
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    sludge2sludge2 Member Posts: 1
    I own a 2000 suburban with a 5.3 liter engine. when I restart a hot engine I somtimes here a pop knock noise. The problem is that it doesent happen all the time. the dealer herd the knock once , and said it is normal. Does any body else experience this problem on a hot restart, and have any idea what causes this. again it doesent happen all the time
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    PAmanPAman Member Posts: 207
    Jason, (AKA the noisy Ford owner posting messages as modvptnl)

    You really are acting like a spoiled baby that just won't shut up. Between the fact that you don't own a GM truck, and you seem to be more interested in trying to sound funny rather than make any substantial contribution to the conversation, I have trouble finding any LEGITIMATE reason for you to be in here.

    To the REAL Chevy owners,

    As for the original question, I have a couple of suspicions, but I'm going to ask a friend of mine that owns his own auto repair business, has 20+ years of repair experience, does TWO radio call-in shows for auto repair; one on a San Antonio station, and one in Houston. He also owns a '99 Chevy Silverado with the 5.3 engine. I suspect that he will point to the filter, which may not have the correct anti-drainback valve, causing the engine to start with a near-empty oil filter the first thing in the morning. The other cause may be the detergents in the synthetic oil loosening some deposits in the engine and partially blocking an oil passage.

    When I get the information, I'll gladly provide it to anyone that would like to find out what he said. However, I won't be bothering to post it in here; I've learned from experience that the best way to deal with an unruly baby is to not give them what they want the most. In the case of the little boy named Jason, it seems to be attention at someone else's expense.

    Anyone wanting to know what he says can e-mail me. I'll be glad to help any Chevy owner with an engine problem.

    Joe
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    seeligseelig Member Posts: 590
    been there done it with (wink wink). best thing to do is ignore.
    your info is most interesting, and don't worry about the puns. considering who they come from, they hold little value. no apology needed.
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    erikheikererikheiker Member Posts: 230
    Regarding the anti-drainback valve...since the opening on the 5.3 filter is on the top, the anti-drainback valve is totally irrelavent. There will always be oil in the filter. It's more of an issue in side mounted applications.
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    modvptnlmodvptnl Member Posts: 1,352
    Will you please answer ray's question?? Since you're sooo knowledgeable.

    What's funny is that your drain back valve theory may be the culprit. But like CAFE you have the mechanics wrong. The valve keeps the oil from draining from the oil passages, not the filter. A bad valve lets oil back in the filter FROM the motor. Like Eric stated, once started, your filter is usually full. I apologize in advance if doubting your wisdom insults you in any way.

    Stop winking, mike. I know you miss tim and all but I don't think Joe will let you have a sleep over.
This discussion has been closed.