Jeep knocking,but don't want to answer!!!
05-05-2009, 10:04 PM
#1
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Model: Cherokee
Jeep knocking,but don't want to answer!!!
I have a 93 jeep that is making a knocking sound only when it warms up a bit!!!!. I have tightened up the torque converter bolts that were loooose!! I don't hear it right on start up,only when it warms up
. I have recently changed oil and have been running it and there is no filings, oil looks clean. It also has lots of power and the clacking sound doesn't seem to be as bad at higher rpm's. I read on hear somewhere to remove the fan belt and see if it goes away could be water pump.. Hmmm!! Well what do you guys think!!!
. I have recently changed oil and have been running it and there is no filings, oil looks clean. It also has lots of power and the clacking sound doesn't seem to be as bad at higher rpm's. I read on hear somewhere to remove the fan belt and see if it goes away could be water pump.. Hmmm!! Well what do you guys think!!!
05-06-2009, 09:14 AM
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Year: 1987
Model: Cherokee
Engine: 4.0 liter RENIX I-6, DIY Cold Air Intake, 2.5 FM Exhaust, 3 Core Radiator
I have knocking all over at idle warm or cold. Soon as I rev. past idle it all goes away. Just the noises of a motor getting tired after 248K of being flogged by me.
05-07-2009, 10:56 PM
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Well i tried taking off the fan belt annnnndd!! no that didn't help
. I think next i am going to drop the oil pan and see if there's anything loose under there. Is it possible to change a bearing under there if i find a bad one to get some extra miles out of this engine until i find a nother one??? If i don't find anything there i guess i willpull the tranny and see if the crank bolts are loose and if there's a cracked flexplate. What do you think???
. I think next i am going to drop the oil pan and see if there's anything loose under there. Is it possible to change a bearing under there if i find a bad one to get some extra miles out of this engine until i find a nother one??? If i don't find anything there i guess i willpull the tranny and see if the crank bolts are loose and if there's a cracked flexplate. What do you think???
05-08-2009, 07:59 AM
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Year: 1994
Model: Cherokee
Engine: 4.0 High Output
How does your oil pressure look? and hows is your compression? I read an article last night that said if you hear knocking or unusual noise from the motor when it is cold while quickly reving the engine to 2000 rpms then you most likely have bad main bearings and you need a rebuild. Get a mechanics oil pressure gauge, install it where your temp sensor goes, If the pressure is high when cold and once it warms up to normal operating temp you are getting no less then 10 lbs pressure while idling between 700-750 rpms and the engine did not knock when it was cold your bearings are probably OK. If it starts out cold with good pressure but then the pressure is low while driving but still has at least 10 lbs when idling with no knocking its probably the oil pump. Hope this helps.
05-08-2009, 09:49 AM
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Year: 1991
Model: Cherokee
Engine: 4.0 I6
Mine knocks alot too, 191k on a 1991 4.0. I made a video of it. I don't think it does it until it warms up some, but I'm not positive. I'll check tomorrow and see. Here's the movie.
Edit to add: I forgot to mention, it drives fine once I hit the gas. It seems like the sound goes away when the rpms go up and the engine is under load. Any ideas? Think it can be fixed?
Edit to add: I forgot to mention, it drives fine once I hit the gas. It seems like the sound goes away when the rpms go up and the engine is under load. Any ideas? Think it can be fixed?
Last edited by jaqattack02; 05-08-2009 at 09:54 AM.
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05-08-2009, 05:22 PM
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Year: 1991
Model: Cherokee
Engine: 4.0 I6
05-08-2009, 05:38 PM
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Year: 1998
Model: Cherokee
Engine: 4.0
If the knock doesnt get louder with rpms...than i would suggest worn out lifters....all the cases of rod knock i have seen gets horrible with more RPM. Also on a high milage engine i wouldnt suggest puting in new bearings...without the crank being check and turned.
05-08-2009, 05:44 PM
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Year: 1991
Model: Cherokee
Engine: 4.0 I6
That's what we were thinking, because it goes away when the oil pressure goes up. We're going to do a compression test this weekend, and see how that look's. I'm also gonna try running a bottle of Marvel Mystery Oil through it and see how that does, maybe it will clean something out and get things flowing. We're considering pulling the head and putting in a set of new lifters, since they're only like $5 each.
05-08-2009, 06:51 PM
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Year: 1998
Model: Cherokee
Engine: 4.0
actually 3.50 a piece if you get the speed pro set from summitracing. I am in the process of replacing mine now. I wouldnt suggest wasting your time on the mystery fix oils.......nothing will fix a colapsed lifter. Thicker 20w50 oil will help. But ultimantly replacement is the cure.
05-08-2009, 07:02 PM
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Check the flexplate my "89" did the same thing. I took the cover off the bell housing and turned the flexplate back and forth with a screw driver. And I saw play on the flexplate to the crankshaft. I was so happy to find out I only had to pull the tranny. 
Heres a pic with the crack highlighted.
Heres a pic with the crack highlighted.
05-08-2009, 08:26 PM
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Model: Cherokee
How does your oil pressure look? and hows is your compression? I read an article last night that said if you hear knocking or unusual noise from the motor when it is cold while quickly reving the engine to 2000 rpms then you most likely have bad main bearings and you need a rebuild. Get a mechanics oil pressure gauge, install it where your temp sensor goes, If the pressure is high when cold and once it warms up to normal operating temp you are getting no less then 10 lbs pressure while idling between 700-750 rpms and the engine did not knock when it was cold your bearings are probably OK. If it starts out cold with good pressure but then the pressure is low while driving but still has at least 10 lbs when idling with no knocking its probably the oil pump. Hope this helps.