Slight knock on start up - not every time

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Kraziken, Jun 1, 2009.

  1. Kraziken

    Kraziken Rockstar 100 Posts

    Just recently, I've noticed slight knocking, no more than two or three seconds, when I first start up the Burb.

    I've checked oil levels, everything seems to be fine. I use quality oil. Normal runs between oil changes I don't see much oil consumption, if any at all.

    Doing some research, do I have the dreaded piston slap? If so I suspect there is nothing I can do about it, but just wondering if any others experience this. My ride is a '98 with 95k on the odometer, so pretty low mileage for the year.
  2. firstkaw

    firstkaw New Member

    I've had 3.1, 3.4, and 5.7s and they all had piston slap.
  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    My 6L does that on cold mornings. They say it's normal. The one and only thing you can do is use good oil and filter. Remember the first few cranks are the critical ones and 5-40 oil will fill your oil system faster than 10-40. So use good oil and stay away from cheap filters.
  4. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Lots of good info on the forums here about piston slap. Just search engine knock or piston slap. GM came up with some coated pistons for customers who complained loud enough, probably easier just to wait for the engine to warm up before you drive it. My dad had a 396 Chevelle and he convinced the dealership to repair the engine to eliminate the noise.
  5. benhartholt

    benhartholt Rockstar

    I have the exact same thing, usually on cold mornings.. mine's a 99 sierra with 314 km's... its nothing serious though so no worries!
  6. jtriplett

    jtriplett New Member

    My 1999 Suburban with the 5.7 and 125,000 miles started doing this at some point in the last 30,000 or so. I am waiting for it to either keep going or have catastrophic failure. :) I have been using Castroil 10-40 and a Fram filter for 7 years.

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