Well this is my first post on this site, i have been lurking around here for about a year getting info when i have been needing it, never had the need to post.. Well i had developed the usual 4.0L lifter tick ( or so i think) about a month ago after my jeep sat for a year.The Cherokee has 360,000kms on it and is a 1991.

I changed the oil, added some type f trans fluid, ran it for almost a 1000kms this month. I ran some Wynns engine flush through it for about 10 mins, and changed the oil again, with some 10w30 castrol high mileage, and a new WIX filter today. Well i am still hearing the tick come and go, and it does fluctuate with RPM. it seems to be coming from the back cylinders. I am thinking its probably a bad / gummed up / semi collapsed lifter .( i hope)

From my searching i hear that it could be some other issues, like piston issues, or flex plate bolts.

So i go out, remove the inspection cover, and check my flexplate to torque converter bolts and they are all tight.. This is definilty not an exhahust tick, as it got a brand new exhahust manifold, and pipe all the way out the back a year ago when i took it off the road.

So basically my questions are ,

a. Has anyone replaced the lifters and head gasket on a high mileager and not had the head resurfaced?

b. is it recomended to change the pushrods and rocker assemblys with the lifter replacement or can i re-use my pushrods and rockers?

c. Any other things i can check before i tear this sucker apart? this is my DD right now as my old DD (monte carlo) was stolen.


Thanks for any and all input

 

The head and block rarely warp on a 4.0. No problem removing/reinstalling the head without having anything machined. Check with a straightedge/feeler gauge if you like.

You can re-use rockers/pushrods unless they are damaged, bent or worn. I roll the pushrods on a glass tabletop to check for bends, clean out the oil passages and check the ends for significant wear.

You might try a gentle, long-term cleaner like MMO before you pull the head, sometimes that gets the lifters unclogged. The noise is annoying but not harmful.

What do you have for oil pressure at idle? Does the noise disappear above idle?

 

MMO it may take a few oil changes but it should take care of the tick (alot easier than pulling the head)....... cold weather makes the tick sound worse.
90 sport, 5spd, 431,000 had the tick since I bought it with 248,000

 

I am one of the less fortunate people that only have the dummy lights on the dash, and no oil pressure gauge.. so i have no idea what the oil pressure is like.. i am going to remove the valve cover tommorow and pull the pushrods and see if any of them are plugged and check out the rockers for wear. i have owned this xj for about 5 years, and have always heard a slight knock, but not this "tick, tick, tick, tick" that comes and go's.
I will see if i can find this MMO around, but havent seen it at our local Lordco Autoparts store, or the local Napa.
Thanks for the input guys, and i will post some pics tommorow of the condition under the valve cover and the condition of the rocker arms

 

Try this.

With what you've got in the crankcase, parked with the engine warm, hold it at 3500 RPM for 3 minutes. Let it idle for a minute and shut it off.

It may take a few times to complete the job. MMO is certainly good to add.

 

pulling the valve cover may not always be needed unless you just want to take a look. If you happen to have an AC gauge lying around it will screw into the oil pressure sending unit hole, and you will get an accurate reading without having to pull the valve cover. But you have to have the kind of gauge with the threaded nipple.