[Mud Marine]

So when I am in neutral and idling under 1000 RPM, my jeep sounds like a Mercedes Diesel... Its a 94 I6 5spd, has full oil, idles at a normal temp and the oil psi is 40-50psi (if I remember correctly) Is this a normal jeep sound or do I need to fix something?

and yes I did a search but I didnt find anything on this yet

thanks in advance

 

[papabear]

Is the manifold cracked?

 

[JR650]

they rattle a bit, but not overly loud. mine has rattled as long as ive had it, but im pretty sure its a lifter rattle and it is consistant and on all 6 cylinders, hasnt changed in 50,000 miles of hard abuse so i assume its normal.

 

[Mud Marine]

Nah, the manifold is fine. I was kinda thinking what JR650 was saying, loud lifters. I had a nissan 720 pick-up that had loud lifters but they werent this bad... thanks for the help guys

 

[fishotro]

crankshaft bearings going out?

 

[Mud Marine]

not as far as I can tell, the sound goes away with the throttle above 1000rpm, especially in gear

 

[rrrcliff]

So when I am in neutral and idling under 1000 RPM, my jeep sounds like a Mercedes Diesel... Its a 94 I6 5spd, has full oil, idles at a normal temp and the oil psi is 40-50psi (if I remember correctly) Is this a normal jeep sound or do I need to fix something?

and yes I did a search but I didnt find anything on this yet

thanks in advance

My '95 Cherokee with the same motor has made that sound for over 260k miles, no issues (yet).

Cliff

 

[Mud Marine]

yeah I got 171??? so I think I may just put a new oil pump on it and see if that does anything. I just bought this jeep and I dont think the previous owner changed his oil as often as he needed to, it has a little bit of build up... nothing a little ATF cant fix though :smokin:


*EDIT* I thought rrrcliff said his xj didnt make that sound. (its 130 am, time for bed and boo work) So I will probably just live with it

 

[Rapoza]

Same issue in my wrangler. These engines are known to do a lot of noise. It has to do with piston and cylinder design. I also learnt that if you have the lifters a little worn or dirty (poor oil changes) they make noise on the valvetrain.

I'm putting together a stroker and I'll replace the lifters/rockers in steps so I can see what is exactly the problem.

Uhmm, perhaps you can replace the valve cover and look inside of it. When I done that, noticed that vertical marks where made by two rockers (nrs 5 and 6). The cover was somewhat misaligned.

Other than that is normal hearing that noises coming from the 4.0L

 

[jpfrk2001]

My 93 motor is about 120K on the clock and quiet. My dads 96 ZJ is at 180K and quiet.

Does the sound go away after warmup? I don't have a warm and fuzzy with your situation. Valve train might be excessively worn? Bad oil changes or lack there of can contribute. Oil pump going out? Low oil Pressure at Idle?(>15psi)?

 

[Mud Marine]

My 93 motor is about 120K on the clock and quiet. My dads 96 ZJ is at 180K and quiet.

Does the sound go away after warmup? I don't have a warm and fuzzy with your situation. Valve train might be excessively worn? Bad oil changes or lack there of can contribute. Oil pump going out? Low oil Pressure at Idle?(>15psi)?

The sound is there hot or cold, but only at idle, when I drive it goes away and the engine sounds 100% healthy and it has great oil pressure, and I'm with you on the not so warm and fuzzy feeling
but I am gonna have to look into what rapoza was saying.