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2.5L Engine Rattle?

23K views 10 replies 5 participants last post by  jeeplover83 
#1 ·
I have a 99 TJ with the 2.5 @ 98,000 miles. My problem is the motor rattles like no tomorrow. The sound is definetly coming from the valve cover. Just want to know if this is a common issue with this motor and what the fix is. I am not an inexperienced mechanic. Have been a garage wrench for a lot of years, I just want a little heads up before I go tearing the valve cover off and I am confronted with something I have never seen before.
Thanks in advance for your help.
Jim
 
#2 ·
One man's rattle.....

Not to be a smart ass but are you sure it's a rattle?

I just played this game for three visits with our Saturn.
There was a rattle coming from the right front strut tower.
The Saturn "technicians" were unable to locate a rattle.
On the third attempt I started making a stink and all of a
sudden the rattle was infact a "suspension knock".

JA's with comuters do not equal mechanics!

Sure it's the valve cover area and not CAT?
 
#4 ·
Absolutely sure the sound is coming from the valve cover. It is for sure not a suspension issue. This is a rattle from the valve cover, sounds to me it could almost be a collapsed lifter. Just looking for someone here who might have some experience with the 2.5 that could point me in the right direction.

For the record, I have worked on vehicles in one capacity or another for 17 years. Started out working in a muffler and brake shop, got my certs and then began working in dyno labs on prototype engine testing. Like I said I have just never had one of these engines apart and would like a heads up before I start tearing this thing apart since it is my daily driver and I can't afford to have it down for an extended period of time.
 
#5 ·
Well its hard to determine the sound of a knock like that withought hearing it.

Just a theory.
But my 95 Cherokee had what I've head refferd to many times as Piston Slap.
Basicaly there is enough materal worn off the cyclinder and piston skirts its clicking aginst the cyclinder wall on the power stroke. Almost sounds like a quiet desiel. And because it always happens at the top of the poser stode it sounds like its happening in the head.



But also compleatly quite possible you have a lifter that went flat, but if that happened it would be running horribly rough.

I would lean more towards either the first thing, or you have have excessive valve wear and the rockers need adjusted back to spec. If its running fine otherwise.

Nothing special with these engines, basicaly half a pushrod v-8, other than it is a PITA to remove the lifters.
 
#7 · (Edited)
Yes they are pedistal mount, sorry about the adjust part, had my hand in too many honda engines.

Other than valve cover gaskets and timing cover gaskets, I've never had to mess with a valve train in a 4.0 or 2.5 even with 200K miles, thew in a head gasket decked the block and head smammed it back together.


An intresting read. and some good illustrations

http://www.angelfire.com/my/fan/roller_rockers.html

The pain about the lifters in these engines is the heads have to come off to remove them. see the third part of that how to.
 
#11 ·
Yes they are pedistal mount, sorry about the adjust part, had my hand in too many honda engines.

Other than valve cover gaskets and timing cover gaskets, I've never had to mess with a valve train in a 4.0 or 2.5 even with 200K miles, thew in a head gasket decked the block and head smammed it back together.


An intresting read. and some good illustrations

Yella Terra Roller Rocker Installation Jeep 4.0L Engine

The pain about the lifters in these engines is the heads have to come off to remove them. see the third part of that how to.
i would have to agree i spent almost three hours trying to replace the lifters if you have any questions just ask i will try to respond to your post as soon as posible
 
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