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Cold Knocking

Discussion in 'GM Powertrain' started by ippielb, Nov 2, 2009.

  1. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    So, i just recently changed my oil for the winter season from amsoil 10w-30 to 5w-30, and now when i start my engine, i can hear a cold knock, it is most noticeable from the front drivers side wheel well, is this my exhaust manifold? Or could it be a even larger problem. I had a code thrown a couple months ago for my knock sensors, but i thought nothing of it because it turned off in 3 days. I still have the knock sensors and the intake gasket, could my knock sensors be the problem?
  2. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Changing the sensors will not have any influence on the cold knock. It could be an exhaust leak, lifter, piston slap. Normally a piston slap can be heard from both wheel wells where an exhaust leak would be louder on the side that was leaking.
  3. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    Well, from the passenger side, i think it's there too, but it's muffled from my cold air intake. I'm thinking it's a lifter, personally, a lot of the chevy trucks we've had, had the loose lifters.
  4. hcm2009

    hcm2009 New Member

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    Last edited: Nov 4, 2009
  5. b_burdine

    b_burdine Rockstar 100 Posts

    it's probably piston slap. Mine does it too. Youtube the piston slap and see if that is what it sounds like. It doesn't harm it but if it gets worse it could.
  6. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    It only does it during the cold start, it doesn't do it when it's under load or during acceleration, it does, only until the engine is warm. And then it stops making the knocking.
  7. ippielb

    ippielb Epic Member 5+ Years ROTM Winner 1000 Posts

    I've noticed, that the last start, it was getting louder, i'm starting to really get worried about this, i don't have another vehicle to get to work, and if something goes, like a piston ring, then i'm pooched.
  8. rdnkchvy2000

    rdnkchvy2000 New Member

    i had the same problem for years with my truck. it only stopped when i switched to castrol gtx high mileage. i do the same winter swap in the weight also and havent heard it since. hope this helps.

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