wierd noise while running?
07-26-2017, 06:58 AM
#3
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Did you check the flywheel for backed out bolts or cracks? Does it make the sound cold and hot? I assume it follows engine rpm? How is your oil pressure? What is the condition of your serpentine belt?
07-26-2017, 10:58 AM
#4
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Year: 1997
Model: Cherokee
Engine: 4.0L
Sounds louder underneath but from what i couldnt say without actually being there. Does it get louder or increase in speed when you give it gas? That could point to the engine or even those convertor bolts. Buy a stethoscope and see what you can find, mechanics use them too. Crawl under it and try to track it down. Check in front of the engine, around the oilpan, and transmission. And everything around them.
Last edited by fb97xj1; 07-26-2017 at 11:01 AM.
07-26-2017, 12:42 PM
#5
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Year: 1998
Model: Cherokee
Engine: 4.0L I6
It's quieter when cold but once it's hot you can hear it a lot more and if you tap the gas it'll go away it's only a idle when it does it belt is fairly new same goes for torque converter I did that when I did the 4wd swap in November but didn't check the flex plate is the flex plate accessible without dropping the trans?
07-26-2017, 01:36 PM
#6
CF Veteran
Yes the flywheel to converter bolts are accessible after removing the dust shield on the bottom of the trans bellhousing. Check those first.
The issue with the sound increasing with warm-up, decreasing with rpm increase and constant at idle makes me think rod bearings. If anyone has any other ideas of non invasive tests/inspections I would do those first but you may be looking at the removal of the oil pan to inspect for bearing material. That would involve draining the pan into a filter media (I like kidney stone traps) then removal of pan for further inpection.
I had an engine with less than 2k on it with perfect oil pressure that shredded #4 rod bearing. Same symptoms. Again I hope someone has another diagnostic step that I have forgotten.
The issue with the sound increasing with warm-up, decreasing with rpm increase and constant at idle makes me think rod bearings. If anyone has any other ideas of non invasive tests/inspections I would do those first but you may be looking at the removal of the oil pan to inspect for bearing material. That would involve draining the pan into a filter media (I like kidney stone traps) then removal of pan for further inpection.
I had an engine with less than 2k on it with perfect oil pressure that shredded #4 rod bearing. Same symptoms. Again I hope someone has another diagnostic step that I have forgotten.
07-26-2017, 03:24 PM
#7
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Year: 1998
Model: Cherokee
Engine: 4.0L I6
We dropped the pan about a year ago because I needed to install a new one we didn't look real close at the bottom end but had nonmetal shavings and my uncle ( whose been a mechanic the last 30 years) said everything looked in good working order but the motor has 259,000 on it with a top end rebuild I assume it to be the original block but am not 100% sure thank you for your input
