motor knocking
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CF Veteran
Joined: May 2011
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From: Partlow, va
Year: 1994
Model: Cherokee
Engine: 4.0 i6, 307 injectors
My motor has had a knock for a little bit now I here it more now what can I do? Also how long will it take to pull it out and a new one put in
CF Veteran
Joined: Oct 2009
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From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
Try running a heavier oil. I run 5w40. Didn't really have knock, but there was little noises that the heavier oil cleared up. I ran the 5w because of winter. If you're knocking, I'd suggest sticking with a 10w40.
CF Veteran
Joined: Oct 2009
Posts: 2,867
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From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
CF Veteran
Joined: Apr 2009
Posts: 4,734
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Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Don't use Lucas. Drain the oil, change the filter using a good brand, and put good 10W-30 in it with no additives.
A thicker oil strains your oil pump and doesn't lubricate the bearings as well.
Thicker oil doesn't prevent or cure engine wear. It actually accelerates it.
A thicker oil strains your oil pump and doesn't lubricate the bearings as well.
Thicker oil doesn't prevent or cure engine wear. It actually accelerates it.
CF Veteran
Joined: Aug 2011
Posts: 10,489
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Did you check the torque converter bolts? They are known to loosen and knock like hell. And Amen ^...my pump must be REALLY strained, pushing that 30W for 263,000 miles. (OK only the last 120K for sure!)
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CF Veteran
Joined: Jul 2011
Posts: 3,235
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From: Elkton, Maryland
Year: 1998
Model: Grand Cherokee
Engine: 4.0
PM Bohnett and see how far he is from you, he may be able to stop by and help you idenify the problem.
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
What brand of oil filter are you using?
And the torque converter to flexplate bolts, if you have an auto trans, and has already been suggested, is where I would start.
And the torque converter to flexplate bolts, if you have an auto trans, and has already been suggested, is where I would start.
Thread Starter
CF Veteran
Joined: May 2011
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From: Partlow, va
Year: 1994
Model: Cherokee
Engine: 4.0 i6, 307 injectors
Originally Posted by pulltabmike
A little more info please....Mileage, oil pressure, last tuneup. Is the knock coming from the bottom of the motor or higher up? Could be a couple of reasons that do NOT require a rebuild or new motor.
PM Bohnett and see how far he is from you, he may be able to stop by and help you idenify the problem.
CF Veteran
Joined: Oct 2009
Posts: 2,867
Likes: 16
From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
Don't use Lucas. Drain the oil, change the filter using a good brand, and put good 10W-30 in it with no additives.
A thicker oil strains your oil pump and doesn't lubricate the bearings as well.
Thicker oil doesn't prevent or cure engine wear. It actually accelerates it.
A thicker oil strains your oil pump and doesn't lubricate the bearings as well.
Thicker oil doesn't prevent or cure engine wear. It actually accelerates it.
CF Veteran
Joined: Aug 2010
Posts: 1,150
Likes: 1
From: Nashville, TN
Year: 1997, 1993
Model: Cherokee
Engine: 4.0L
Ok its a out 230,000 miles index at running temperature going 55mph the oil pressure is at 40psi, and the knocking is hard to tell if you r under the hood it sounds like it is on top but if u are going into the cab with the door open it sounds like its coming from the bottom, and I am using mobile1 oil and frame oil filter
Get rid of the fram filter. I know some people say they run them and are fine but I've used them in the past and my engine runs quieter now that I've switched brands. Go with Napa Gold (made by wix), wix, mopar, Mobil 1 or Motorcraft oil filters.
Thread Starter
CF Veteran
Joined: May 2011
Posts: 3,380
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From: Partlow, va
Year: 1994
Model: Cherokee
Engine: 4.0 i6, 307 injectors
Originally Posted by pulltabmike
A little more info please....Mileage, oil pressure, last tuneup. Is the knock coming from the bottom of the motor or higher up? Could be a couple of reasons that do NOT require a rebuild or new motor.
PM Bohnett and see how far he is from you, he may be able to stop by and help you idenify the problem.
CF Veteran
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
The Orange Can Of Death.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
The old OCODs. More than likely the singlemost cause of bearing failure in our beloved 4.0s.
That said, it sounds like the OP may have loose TC to flexplate bolts since he has good oil pressure. Have we determined he has an auto trans?
That said, it sounds like the OP may have loose TC to flexplate bolts since he has good oil pressure. Have we determined he has an auto trans?


