One last hope of identifying this noise

[clunk]

Your exhaust is very close to the crossmember and supported by the tranny mount. If you tranny mount is old and oil soaked it will give when hot and let the exhaust rattle on the crossmember. :banghead:

haha, well..my exhaust has been rattling on the crossmember for the past 3 months..it's just something Ive gotten used to by now.

Thanks for the suggestions. I'm going to pick up a 'proper' mechanics stethescope this weekend and really spend the time to try to track it down. Might pull the valve cover if I get especially motivated, but it's supposed to hit 104 degrees this weekend, so it might not be the most fun to work in the driveway in that kinda heat.

 

[outlander]

I second the cracked manifold...had this on mine and I almost tore into the motor thinking that it was in the motor.

Also could be a lifter bleeding off pressure....do a vacuum test to determine if the noise is in your valvetrain

 

[ColoradoJeepXJ]

I had the same sound on a 2.5L, rear top end. I replaced the hydraulic lifters and never heard it again.

 

[steevej]

I really hopat you guys figure this out. I have exactly the same problem with my 96 4.0 HO Cherokee Sport
Had some folks volunteer to come by and look-see... but life got in the way and none have come by so far.
I want to 'give' the Jeep to my 2 teens, but the way it sounds (Tika-Tika-Tika) leads me to believe that 'something' will bust, and at the worst poss. place and time.

Keep me informed.
I do Computers and Networks for a living and most all of this info is much appreciated and very new to me ;-)

 

[Hellbent]

third vote for crack in the exhaust manifold. i've heard some of them sound exactly like that; quiet when cold, but noisy as hell when they start to warm up.

 

[jeepdeez]

how would you check the exhaust manifold?

 

[hawk_sixsix]

Same mystery problem here; 97 XJ 4.0L Reminds me of an old 80's diesel Mercedes, it's not a typical dieseling sound, but a clackita-clackita-clack sound. Has anyone figured this one out yet?

 

[sidedrifter]

My 89 had it and when we took it apart it was the back cylinder being out of round and making the piston slap.

 

[wishbone]

how would you check the exhaust manifold?

Run a can of seafoam and watch your exhaust manifold. mine was always loudest when cold, then quiet when warm

 

[hawk_sixsix]

My 89 had it and when we took it apart it was the back cylinder being out of round and making the piston slap.

Wouldn't that be affected by load on the engine? This doesn't seem to change with hard acceleration.

 

[joe_peters]

Go buy yourself about 3 feet of clear vinyl tubing, most auto parts stores or hardware stores carry it, and stick one end in your ear and move the other end around the engine compartment until you can isolate the location. While a mechanic's stethoscope is good for many problems it will pick up resonating noises and can confuse even professionals.

Try the tube.

 

[xj88kjetil]

I had similar sound from my 88xj, although only at 1400rpm and up. Had many experienced mechanics listen to it with stetoscope. All agreed: the sound seemed loudest along the right side of the cylinder head... impossible to pinpoint if it was in the front or in the back....

Found problem only when I thought of checking my rod-bearings... Completely worn out, and deep grooves in the crank.... replaced crank and bearings - sound gone....

Notice this!!!!!! : None of the mechanics suspected this was the problem! It did NOT sound like worn rod bearings!!!

(my XJ has only run 125k miles)

 

[Davinator61]

Check my post on the "Engine Noise With Video/Audio Link" thread for a possible cause and fix.