Thursday, November 29, 2012

Knock, Knock, Knocking under the hood...

The loud engine noises I have been complaining about for months (if not longer) are still here and stronger than ever. I'm getting to the point where I don't even like to drive my car anymore as much because it's emberassing when your engine is making more noise than the diesel truck next to you at the light.... It's not even the typical 'sewing machine' noise people say is typical for an LS-engine. I HAD that noise way back when and that actually was a fairly decent engine noise since it sounded like it was running smooth. Here I captured a particular bad morning of what sounds like a couple of monkeys with hammers under the hood trying to hammer their way out.

I've been reaching out to people about the possible causes of this and doing some research myself and have come up with the following (fairly long) list of issues

First the 2 nastiest possibilities - Internal Engine issues:

  • Excessive Clearance / Piston Slap
  • Rod Knock

Then there's possible valvetrain related issues:
  • Collapsed Lifter
  • Pushrod issues: Either bent or Pushrod too short / Not enough preload
  • Rocker hitting Valve Cover Baffle
  • Broken Valve Spring/lock/whatever
  • Rocker 'Loose'
Now I'll have to either start digging into this myself or once again find a trust-worthy shop to look into this that will actually properly investigate and fix the issue.

Obviously I'm hoping it's something simple like a just a pushrod issue, but I'm actually half-tempted to go get some Link-Bar Lifters, new pushrods and just replace the whole deal and then see where we end up just for peace of mind.