Hot Engine Knock

Discussion in 'GM Powertrain' started by Lil_Red_Chevy, Jun 7, 2011.

  1. Lil_Red_Chevy

    Lil_Red_Chevy Rockstar

    Hey Guys,

    I've got a 04 1500 with the 5.7l v8. It had a very slight issue where the rpms would "lunge" when the engine was cold Sometimes . I just finished a 3 1/2 hour drive and my engine now has a quiet knock (like a diesel). The engine has not had a chance to cool down yet. I'm at just about 115k miles and I was gunna give it a tune up, but I just wanted to know what you guys think. thanks
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    Any knock that wasn't there before is a bad sign Red. See if you can localize it to the oil pan. Since it's a soft knock, I would guess it's still in the beginning stages so if you address it now you may save the crank.
  3. Lil_Red_Chevy

    Lil_Red_Chevy Rockstar

    well i checked the oil and it was pretty low. I would of thought a code or something would of popped up first but I guess low oil aint that important :) So changed the oil and the noise got even quieter, but unfortunately I think you may be right. It sucks cuz I'm supposed to haul me two buddies and a boat up to northern michigan next month. I've only had the truck for a few months now and only put about 4k on it and so I'm pissed. oh its a 5.3l v8 not a 5.7l i dont know why I put 5.7

    Also the rare inconsistent idle problem I'm having/ the little bit of white smoke coming out my tail pipe tells me I could have a head gasket problem. fml
  4. stephan

    stephan Rockstar 4 Years 5000 Posts

    That does suck. With two possible major problems, I wouldn't drive it any more. The sooner you repair it the fewer parts you'll have to replace(especially the crank). We caught a bearing knock right away & the crank wasn't even hurt. The journals were still round & not scored. If you didn't put too many miles on it, it can be saved. It might have just started at the end of your trip.
  5. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    On the flip side it sounds like it could be the 5.3L famous lifter noise come to haunt you. How is the oil pressure? and as to the idle problem if you havent ever cleaned the Throttle Body i would do that ASAP since that is a huge problem with these trucks once they get some carbon build up into the TB that they run poorly. Also a tune up wouldnt be a bad idea..
    as to smoke what color? and are you using anti-freeze? since up here we are still getting some white smoke on start up etc thanks to the high humidity and warm temps.
  6. Lil_Red_Chevy

    Lil_Red_Chevy Rockstar

    Ya the humidity is usually pretty bad here too just not recently. Its white smoke and it is dexcool antifreeze.

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