I have a 99 XJ w/ a 4.0 that has a slight knocking sound. I was told by a "Jeep" guy at a shop that it was just a lifter making noise not a rod.. He said it was common on 4. liters. Anyone have any imput on this??

 

And or the "old piston Slap".

Pretty common in higher mileage 4.0's. They'll run forever with that tick.

Black89

 

What brand of oil filter are you using?

Ever shine a light into the oil filler hole to assess the sludge build-up in your engine?

 

I just got it a week and a half ago. Had to fix a bunch of things, but haven't had a chance to look at the oil filter just checked the oil. Plan on doin an oil change this weekend. It's gotta 147k on it. Runs good. Havin a few CEL codes popping up that I thought I fixed, but I guess not.

 

Use Wix or Napa Gold filters.

Let us know how it looks through the fill hole.