I am sure there are other posts, but sometime I am just to lazy!

I have heard these have very noisy valve trains. Mine ticks, at idle, once gas is applied it goes away. It has done it for a while, never gets worse and the engine runs fine. But here is the question.... Can the ticking be eliminated or reduced with different oil? I run M1 synthetic, 10W30.

 

they sound like diesels a little bit, minus the nice smell and tq

 

my wife had a 94 cherokee with a 4.0 in it....she ran it until it had about 220,000 miles...we traded it in the other day for a pt cruiser...but anyways, it ran loud....ticked a bit...but we just left it, but i was told that putting some lucas oil in it would help quiet it down a little....but with that motor there isnt much you can do......we put some 10w40 in it and it helped a tiny bit for the time being

 

It's piston slap. It's normal on the 4.0. JIM.

 

I've had two 4.0's - 2KXJ and the 05 Unlimited - and have never had ticking or piston slap issues. Guess I got lucky. These engines are simple and will run forever with minor maint.......
IMO, there is no such thing as normal piston slap. That is why my beloved Avalanche was traded off.

 

My 4.0 had lifter tick which is pretty common on these.

 

I don't remember the year, but they changed the design of the piston skirt to get rid of the noise. It is common & normal on the older ones. JIM.