Alright, I need some advice. My 02' has a random tick coming from the engine compartment. And I am serious about random, cold starts, warm starts, during driving (I can faintly hear it), stop and go, incline and decline. Then it will go away, maybe a couple of days. Then bang it is right back. It idled the other day from a cold start and made no noise for maybe five minutes while it warmed up, then ticked for a short while, went quite again, and then started ticking again. Could last for one minute to an hour. I am guessing it is a lifter? But wouldn't that tick all the time especially at idle? Could it be an injector? Cause I run heavy equipment and when the diesel injectors plug or begins to fail they begin to knock or tick.
The jeeps details, 4.0 liter, owned since new, 151k. Thanks

what oil & oil filter do you run?

It's a 4.0, they make noise...For hundreds of thousands of miles they make noise.

well put.... bought mine with 248,000 with the tick now at 433,000 still ticking, ought to change my plates to say TIMEX.
Oil filter of just about any brand other than FRAM will help(maybe) and some MMO.

mine does that too ticks a little after start up when its cold goes away at 210 ticks in the summer till it reaches 210 also. Its the emissions sensor that damn thing goes up and down and bangs like hell. Maybe that is it, it would be on the drivers side engine comp looks like a cylinder

when the "ticking" occurs does the engine also develop a slight miss? If it does, the problem could be related to a sticking valve from excessive carbon buildup.

So far I haven't found a 4.0 that DOESN'T tick! So far I haven't found anyone that could tell me the source of it either. Some say it's valve lifters, I don't think so because it always sounds like just one and that would be weird. My 00 WJ didn't until 100K and I thought that weird also.

Runs good, starts every time, got good oil pressure. I'm happy!

The only other tick or banging that can occur is caused by the piston skirts(kilts according to some) similar noise but deeper in the engine.

My first thoughts where maybe an exhaust leak. I had a new 71 Cuda
that started ticking with less the 8k on it. Sometimes it would do it for a
couple miles or maybe a couple days. Took it to the dealer and they
swapped out lifters. Couple days later it started again. Now I'm pissed,
so I dropped it a gear and held the gas to the floor for about 1/8 mile.
(go or blow, planned on giving back to the dealer).
Found the tick - left exhaust manifold leaking.

I like your style! Reminds me of a Chevy 283 we thought was carboned it, wrung it out and WHAM! On teardown, we found one cylinder with just a rod and wrist pin in it!

lol, whatever works!
Dave, I sent you a pm

No miss in the engine, damn thing runs smooth.

Yeah I know the 4.0 ticks and rattles and leaves an oil slick everywhere it goes. And valve lifters sound like a maybe except like you pointed out, only one would be weird. The tick is relatively new, I have had the jeep for 10 years and 130k, I feel I am pretty attuned to its noises.

Mobile 1 high mileage 5w-30 and any filter other than a Fram.

I might try the mmo, though I am a true believer in Lucus products. I use them heavily in my diesel equipment and trucks.