Chevy 6.0 Vortec Spark Knock

Discussion in 'Trucks and Trailers' started by Total.Lawn.Care, Feb 5, 2007.

  1. Total.Lawn.Care

    Total.Lawn.Care LawnSite Senior Member
    Messages: 840

    In the older days, we used to deal with spark knock by doing and tune up and adjusting the timing just a little. But, in this 2001 Chevy, there is no distributor. What is the best way to eliminate the spark knock, or do I just need to change the plugs out?

    Also, which plugs do you recommend? I have typically driven Fords, but used to have a Suburban with a 5.7. I always put AC Delco plugs in it. Iwas thinking that due to the spark knock, I might be better off with a hotter buring plug like Bosch. But, I know that you connot put Bosch plugs in some Fords, or it will cause terrible misfiring and skipping. Can Bosch plugs be run in this engine?

    Any other tips will be appreciated...
  2. milsaps118

    milsaps118 LawnSite Senior Member
    Messages: 565

    If your hearing a knocking noise with your 6.0L gasser you have something else going on in there. How many miles are on that engine? Everything is electronically controlled by the computer so their are no adjustments that can be done. The computer will read Cam/Crank signals and make necessary adjustments if a problem occurs. Changing plugs won't do you any good either because your computer is already calculating engine timing according to the spark out puts from your coils.

    I think if your hearing a knocking noise it's due to wear on the motor and its the rods slapping that your hearing or main bearing. If it gets worse your computer will produce an engine "CODE" and that will/should confirm your knocking sound.

    Best of Luck.
  3. Total.Lawn.Care

    Total.Lawn.Care LawnSite Senior Member
    Messages: 840

    It has 103K. I know it is spark knock, probably from some carbon buildup in the engine. I just got this truck a few months ago, and have only put about 5,000 miles on it. It runs great, pulls well, has no overheat problems or anything. My grandfather used to have a Ford Galaxy with a 390cid that had spark knock issues which is how I recognize this one.

    I figured that it probably just needed a good fuel conditioner and de-carbonizer added to a tank or two and maybe a different set of plugs. I am not even sure at this point if it has the recommended plugs in it or not. I will look and see.
  4. chevytrucks84

    chevytrucks84 LawnSite Member
    Messages: 147

    does this happen at all times or just when the engine is cold. I have a 6.0 that has more of cold start knock which are common but once the engine warms up you dont hear a thing i have had 2 5.7 trucks that did the same thing when they were cold

    Hope this helps....just turn your radio up and you wont here it :drinkup:

  5. General Landscaping

    General Landscaping LawnSite Senior Member
    Messages: 801

    I found mine cleared up by moving up to midgrade fuel.
  6. TWUllc

    TWUllc LawnSite Senior Member
    Messages: 406

    Mine knocks for 5 seconds at cold start.
  7. Jacob's Yardworks LLC

    Jacob's Yardworks LLC LawnSite Member
    Messages: 113

    How hard is it and whats involved to change the plugs on the 5.7?
  8. RedWingsDet

    RedWingsDet LawnSite Gold Member
    from Detroit
    Messages: 3,556

    call gm, they will give you a 100k mile waranty. It is common, and not a big deal. My 01 had the problem, chevy gave me a 100k warranty on it. Again, its not a big deal, I wouldnt worry about it. I sold that truck and now have a 06 2500hd and use premium and havent had the problem since new and it has about 7k miles on it now.
  9. Total.Lawn.Care

    Total.Lawn.Care LawnSite Senior Member
    Messages: 840

    Most all of the plugs on the 5.7 were very easy to get to. I think the only one that was even remotely a slight pain was No. 8 (rear pssenger side of engine). I likes the 5.7, it was very easy to work on.
  10. Total.Lawn.Care

    Total.Lawn.Care LawnSite Senior Member
    Messages: 840

    I have a slight ticking when it is cold, as with most gas engines, waiting for oil flow over the lifters. That only started when the weather got down into the 30s and lower 40s here.

    The spark knock only appears under moderate to hard acceleration or when towing heavy load under acceleration. It is not loud, but I know it is there. My wife would never hear it, because she does not know what to listen for.

    I may have to run a tank of mid-grade fuel through it and see if it goes away.

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