So as long as ive owned my jeep the motor has been noisy. Almost sounds like a quiet diesel at idle. It kind of chatters or lightly knocks, but im pretty sure its not a rod knock. I know the exhaust leaks a bit..

What do you guys figure?

 

You arent the first to say that. Thicker oil may shut it up.

 

The oil pressure goes down at idle leaving the valve train to clatter, try some Lucas oil additive (5 quarts oil/ 1 quart Lucas) to help thicken the oil and increase pressure at idle. Just don't expect it to sound like an electric motor.

 

when mine started to get real noisy...i pulled the valve cover, loosened and re-torqued all of my rocker arms, that shut it up really good! i also run 10w40...seams to work great for me

 

thanks for your suggestions. i will definetly try the lucas stuff, ive heard great things about their products.

 

When I first got my XJ (4.0) about 3 years ago, it made a light ticking sound, so I figured I could quiet it down with either thicker oil or a viscosity-improving additive. It immediately got a LOT louder, and it even sounded like a knocking rod. I added even more additive with no improvement. I was ready to pull the head and timing cover and replace the lifters and timing chain and pull the oil pan to check for internal engine damage. Then I was reading one of the posts on CF and someone suggested THINNER oil for a noisy engine. I figured that I had nothing to lose by trying this so I put in only the 10W-30 the manual calls for.
Believe it or not, the engine is back to making only that light ticking sound! The only explanation I can think of is that the oil passages have a very small diameter and the thin oil flows with better volume to the lifters than thick oil. Hope this helps!