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Oh Crap! Got a Knock!!!

B

biggin69

NAXJA Forum User
Location
Hamilton, OH
My 97 XJ 4.0 developed a knock. I thought it was probably the flex plate until I decided to pull the plug wires one at a time just to see. When I pulled off number 5, the knock quit. the jeep has 142K on it. What should I do?
 
Drop the pan and take a look at the bearings ASAP. If you catch it quick enough you can simply swap in a new set of rod and main bearings.
 
park it..

Pull the pan, replacing JUST the bearings right now is a fairly cheap and straight-forward repair.. Keep driving with it, and you will wear out other parts Quickly, Creating a very expensive rebuild.. or, a hole in the block
 
Are you per chance running a FRAM filter?

What was your oil pressure?
 
The question is, why did it happen. Loss of oil pressure, bad oil, abuse? Did it happen real sudden?
 
Fram's have a history of causing loss of oil pressure and destroying 4.0L's. While your pressure sounds adequate, it may not have been at one time. I would slice and dice the filter. Was the previous filter a FRAM? By any chance would you have it?
 
old_man said:
The question is, why did it happen. Loss of oil pressure, bad oil, abuse? Did it happen real sudden?
Click to expand...

I just bought it from a friend I work with. He had it since 06 and seemed to take care of it. It did not do it until I changed the oil. Running Valvoline Max Life 10w-30 and Fram extra guard filter.
 
old_man said:
Fram's have a history of causing loss of oil pressure and destroying 4.0L's. While your pressure sounds adequate, it may not have been at one time. I wold slice and dice the filter. Was the previous filter a FRAM? By any chance would you have it?
Click to expand...

Previous was not a Fram and no I do not have it. So are you saying the filter could be causing the knock?
 
You did check the oil level, right?
 
I would swap the filter and give it a try, but your numbers sound fine.
 
Not always. You could actually have a cracked piston and what you hear is a piston rattle. The best thing to do is pull the pan.
 
Since they started being made in China, from what we can tell, the filter element inside collapses. Haven't heard of it happening on other vehicles, but I have personally been involved in multiple failures.
 
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