I've got a '98 sport xj with the 4.0 and aw4.

Didn't notice this tick before because I had a (very) cracked exhaust manifold and rusted out/vibrating exhaust. That's all good now though.

The tick is constant. It increases with rpms. I don't think it goes away after it heats up. And it is just as present with fresh oil(Rotella t6).

https://drive.google.com/file/d/0BwT...w?usp=drivesdk

Any ideas?

Thanks.
Ryan.

 

To me, it doesn't sound like anything serious. That's a quiet 4.0. So quiet that in fact you may be hearing the ticking of the injectors or just normal engine noise.

 

check the flex plate to torque converter bolts, they have been known to loosen up a little bit. I've also seen the 4wd linkage loosen up a little bit over time and make an annoying rattle sound to some customers. I usually adapt an old drum brake hdw spring to add some constant tension on it so it doesn't rattle. (that particular rattle is generally only heard from inside the cabin)

 

Put your finger or better a stethoscope on the EVAP purge solenoid and see if that is what you hear.

 

Pretty sure it's not the purge solenoid, I can put my ear right on that and it's a very obvious sound. Also the knock increases with idle. And I can hear it in the cab now.

Finally got under the Jeep to check the flex plate. Huge pain to get that inspection cover off when the exhaust is routed directly in front of one of the bolts, I might cut the bolt and get a new one so I can put the nut on that side instead. Two of the bolts were loose. Pulled them out, wire wheeled them, put locktite red and reinstalled. No way my torque wrench is fitting up there so I just got them as tight as I could with the box end wrench.

The sound persists. When I started it I crawled back under and listened close. It still seems like the general area. I can't feel anything knocking with my hand down there. I can't quite reach the block with my hand very easily so I'm going to go get a stethoscope tomorrow.

TL;DR: Not the purge solenoid, tightened flex plate bolts, sound persists and is louder from under the Jeep.

Anyone have an idea?

 

Got the stethoscope. Listened to purge solenoid and injectors with it for reference. I didn't realize how loud those were. BUT I can't help but hear it as a ticking and the noise is more of a knocking... Maybe I'm just going crazy?

 

just for ****s and giggles, try pulling on the 4wd shift lever slightly. I've had a few customers come in complaining of an engine tap just to find out it was a loose linkage banging around.