Metal to metal noise

[offroadman83]

Usually in the morning when my brother starts his jeep it will be fine for a minute or so and then it initiates a semi loud metallic noise and it goes along with the throttle and everything. This noise goes away after the Jeep has been driven for a while, so what might this be?

The jeep is an 89 jeep cherokee laredo, 4.0 with ax15 and np231 with 3" lift.

 

[FatXJ]

exhaust hitting something? that's all I can think of right now unless it's the clutch coming loose.

 

[ACE]

So is the metal to metal noise a tap, tap, tap or a clunk, clunk, clunk kind of noise. You say that the noise varies with rpms as in gets faster with more rpm? Coming from top or bottom or behind engine?

 

[offroadman83]

Hey Ace its a lifter type noise and goes away after 2 to 3 minutes on cooler mornings. Past few mornings the jeep hasn't made the noise long enough to really check where exactly it might be coming from---------Kyle

 

[ACE]

Well if it's a lifter type noise then that's what it probably is, a lifter that is sticking. My '90 had the lifter tick start around 150k miles and had two lifters sticking by 160k miles. You can try to run a high detergent oil like Mobil 1 through it next oil change and see if that stops the ticking. It actually helped mine for about 3000 miles but the tapping soon started again. You can also try one of those pour in engine cleaners but I don't have any experiance with those. I went ahead and got a new long block at the time but you can just put new lifters in. The head does need to be removed to get to the lifters and it is recommended to replace the camshaft when you do the lifters. You can try and isolate the faulty lifter and just replace it but I think it's wiser to just replace all of them as you really don't want to do the job over again when another lifter starts sticking. My Haynes and Chiltons manuel has the procedure for this and they are what I used when I did the job back in '96 or so.
Good luck,