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Anyone get their GM Piston Slap problem fixed by GM ??

Discussion in 'The Lounge' started by 88Silverado, Mar 8, 2004.

  1. 88Silverado

    88Silverado 1/2 ton status

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    Well, after hoping things would get better, the piston slap in my $38000 2002 LS1 is still knocking. Not just at startup (usually dont hear it) but when its warm. Just had the oil analyzed and the report was "Excessive Steel" found. It has 24000 miles and the oil have been changed every 3000 miles.

    Im going to try my dealer next and I bet with no luck. May have to have a borescope done to look for damage.
    Anyone dealt with this problem yet???
     
  2. Confedneck

    Confedneck 3/4 ton status

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    gm had that problem.. they'll tell you to switch to 50 weight oil...
     
  3. mud390

    mud390 1/2 ton status

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    I've got the exact same problem with my 2001 GMC that has a 4.8L in it. Sounds like metal on metal sometimes. Usually sounds like a valve or lifter ticking. I took it to 3 different dealerships and they all told me it was, "Spark knock." One dealership told me try different gas stations. So I did, and no fix. I thought that was a BS excuse anyhow. So I went to a different dealership, and same answer. I told them NO, look at it again. They came back with the same answer. I drove it home (700 miles) and stopped at 4 different gas stations running premium the whole way and it still did it. Doesn't "spark knock" as bad with premium, but its still there. Dealership I bought it from told me "Spark knock with bad gas." I told him BS to his face and they ran it on the diagnostic machine again and it came back with, "Spark knock, timing issue." They tech said he couldn't adjust the time due to the computer and I was just stuck with it. I've never heard spark knock that sounds like a piston slapping a valve before though. It does it really bad when in overdrive around 40-45mph and I step on the gas. It can be really bad when climbing hills too. A friend of mine had a 2001 with a 5.3L and the same problem. He had his intake resealed and never had another problem. They wouldn't reseal my intake though. Said that wouldn't cause the problem. I was thinking possible vacuum leak, but who knows. Hope that answers some of your questions. Sorry this reply is so long.

    Kris
     
  4. Confedneck

    Confedneck 3/4 ton status

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    well the excessive air past leaky intake gaskets could cause a lean condition in the cylinder....
     
  5. mud390

    mud390 1/2 ton status

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    Would that cause a knock like I described though? How did that "quick fix" of 50 weight oil work?

    Kris
     
  6. Confedneck

    Confedneck 3/4 ton status

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    the 50wt oil im guessing just kept better lubrication and muffled the piston slap due to being thicker..

    and yes, leaky intake gaskets can cause some god awful spark knock..
     
  7. mud390

    mud390 1/2 ton status

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    Thats what I figured with the oil. I didn't realize that a leaky intake would cause spark knock like that. My "spark knock" sounds like metal on metal grinding though. Really bad at times.

    Kris
     
  8. 88Silverado

    88Silverado 1/2 ton status

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    Actually GM's first recommendation was to run Mobil-1 oil. That didnt help. The chunks of non-metallic parts I found in the oil drain pan and now the excessive steel has be worrying cuz my warranty expires in 12000 or 9/11 of this year!! /forums/images/graemlins/eek.gif


    BTW, this site has some good info
    Pistonslap
     
  9. Confedneck

    Confedneck 3/4 ton status

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    yeah.. take it in and tell them to fix it..
     
  10. mud390

    mud390 1/2 ton status

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    I usually run Pensoil (Sp?) in my truck. 10w30 weight. The only experience I've had with that is around 5000 miles on an oil change...bad, I know...my check oil light came on, so I checked the pressure, and it was good. Pulled off the road and checked the oil and I was 4 quarts low. Very scary for me. Maybe I should trade my truck in now that I've found out all of this wonderful information.

    Kris
     
  11. 88Silverado

    88Silverado 1/2 ton status

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    Thats alot of oil for a GM engine, however, they say 1 quart/1000 is considered normal also /forums/images/graemlins/rolleyes.gif

    5000 between changes is the max you want to run between oil changes. Oil is usually good for 5000.
    I have heard GM will offer an extended warranty to something like 80000 if you complain loud enough.
     
  12. Muley

    Muley 1/2 ton status

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    [ QUOTE ]
    Thats alot of oil for a GM engine, however, they say 1 quart/1000 is considered normal also

    [/ QUOTE ]

    I thought that was only on the 8.1's?

    Not to get off the subject, but figured I would pass this info long as it maybe helpful

    I have a Pontiac Montana minivan. It is the same as the Ventura or the Shiloute. Well my GM mechanic buddy says that they are notorious for their intake gaskets going bad around 30,000 miles. They will either start pushing oil out the front of the motor where the intake bolts up, or they will start burning antifreeze. Well mine has 64,000 and it has started to consume antifreeze. So intake gaskets very well could be a problem.

    Something else to rant about is the cooling system on the van. I was told by the dealership that the thermo-relay that starts up the primary cooling fan functions properly at 237 degrees. Now since the transmissions in these vans run throught the radiator only, isn't that way to hot? I mean by time you reach 237 for the fan to kick on you have already toasted your transmission.

    Don't get me wrong, I have grown up with GM's all my life and have owned at least one of them ever since I bought my first car. I think they are still better than the rest. Although the Nissan Titan is looking pretty nice. /forums/images/graemlins/whistling.gif
     
  13. got_mud

    got_mud 1/2 ton status

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    i was under the impression that the slap issue was related to non floating wrist pins in the newer gen engines. i know that the 6.0 in my 2003 sierra is doing the same and i have been trying to find the tsb that says dealers can swap to the new engine with floating pins as a last resort/customer satisfaction maneuver. where do we find the tsb's for newer gm's?
     
  14. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    My dads 2000 Buick has the piston slap issue too. I dont think he has taken it to the dealer yet but Im not sure.

    [ QUOTE ]
    where do we find the tsb's for newer gm's?

    [/ QUOTE ]

    Ill look them up today at work on ALLData.. /forums/images/graemlins/thumb.gif
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    "Spark knock." One dealership told me try different gas stations. So I did, and no fix. I thought that was a BS excuse anyhow. So I went to a different dealership, and same answer. I told them NO, look at it again. They came back with the same answer. I drove it home (700 miles) and stopped at 4 different gas stations running premium the whole way and it still did it. Doesn't "spark knock" as bad with premium, but its still there. Dealership I bought it from told me "Spark knock with bad gas." I told him BS to his face and they ran it on the diagnostic machine again and it came back with, "Spark knock, timing issue."

    [/ QUOTE ]

    $1000 that these so called "professional"mechanics (I'm sorry, some of you might be good mechanics, but most are paper qualified morons) are seeing knock retard from the knock sensor due to the piston slap.

    Hey, I could be wrong, I don't have an $XXXX ASE patch on my sleeve, but if they looked at the knock count, and can't see that it's related to the piston slap, well.

    If the knock sensor "sees" knock, it's going to mess with the timing, and unless the cause of the "knock" goes away, timing will continue to be screwed with.

    Maybe a continous knock will set a code in the OBD2 systems, but if it doesn't, it seems very likely the knock sensor is seeing the piston slap, and affecting timing.

    For those of you with vehicles under warranty, sure would suck to have the engine run without oil for awhile, then have it mysteriously refilled. /forums/images/graemlins/whistling.gif

    Sorry, but I think GM's denial that this is even a problem, to save them some money, instead of taking care of their customers, is ridiculous.
     
  16. beater74

    beater74 1/2 ton status

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    GM will never fix this problem. for them to fix a piston slap problem is to admit there is a problem. To admit there is a problem would start the calls for a recall. If any body says that GM fixed there piston slap problem i say BULLSH!T, show me proof /forums/images/graemlins/angryfire.gif

    oh and btw i don't own a newer GM pickup and never will unless it's a duramax/allison /forums/images/graemlins/thumb.gif
     
  17. 88Silverado

    88Silverado 1/2 ton status

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  18. 4by4bygod

    4by4bygod 1/2 ton status

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    GM has been designing their engines with a much shorter piston skirt, in the name of reducing the weight the crankshaft has to turn, thus helping mileage. A longer piston skirt makes the piston more stable in its bore, but a shorter one will rattle around in there, making all kinds of noise. My dads 2000 C5 had the same problem. We fixed it by getting rid of the mobil one oil, and switching to an oil that won't shear off the pistons.

    wrt to a high steel content in your LS1's oil analysis, given your mileage, that's not suprising.. I've seen these things take FOREVER to totally break in.

    Tom /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  19. Emmettology 101

    Emmettology 101 3/4 ton status

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    My father '02 Yukon with the 5.3 has a bad knock at start up also. Even after driving it through town and then only being shut off for maybe 20 mins..... They just give him the run around at the dealer.

    Someone above mentioned somethign about having an intake resealed. Dodges with the 360's had that problem. The intake gaskets would leak causing a lean situation. Once they were resealed in helped but they also needed a computer reflash....
     
  20. 88Silverado

    88Silverado 1/2 ton status

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    Was wondering which oil you switched to?

    The concern with the high settl content is according to the analsis, average content for that engine with that mileae is 15ppm.
    Mine was at 86 /forums/images/graemlins/tongue.gif
    Im afraid the piston rocking is wearing the cylindar wall
     

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