4.0 Question

[90Xjay]

My 4.0 with 155K runs great. Compression is fine. Starts and drives very well.
Every now and then I can barely hear a mild noise that sounds like it is coming from the botton end to half way up the driver side. (definately not exhaust) but still could be lifter. Real hard to tell. You really have to try and listen for it. I have had it for a year and put 2500 miles on it and the sound has not changed gotten any louder.

This is my first 4.0 and I have heard they can produce a minor amount of noise from time to time and do not worrry about it. Some say it is piston slap, which is not really harmful.

Any opinions, ideas, reflections........

 

[Junkpile]

Piston slap not being harmful is an idea that GM and Chrysler would love for everyone to believe. Minor piston rocking IS normal though and the 4.0s are known for it. A buddy of mine bought a six month old 94 Cherokee for a GREAT deal because the original owners returned it because of the noise.....after the dealership had replaced the engine at 5,000 miles and it still knocked. The dealership had like six of them on the lot for the same reason when he bought his.

 

[Tug-n-pull]

All jeep motors are a bit noiesy and leaky aren't they? tug

 

[TwistedCU]

155K miles and runs great means don't worry about a few little quirks so long as they do not become more defined. I'm looking forward to that kind of mileage out of mine!