Engine Knock Wont Stop!
01-26-2017, 09:52 PM
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Join Date: Feb 2015
Location: North Carolina
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Year: 1993
Model: Cherokee
Engine: 4.0
Engine Knock Wont Stop!
Tried everything and I just don't know what to do. All started rend only one day when I jumped in the jeep and left work. Didn't slowly come on, Just randomly started. I noticed it when I stopped at a light.
It only does it at idle and disappears as RPMs rise. Sounds like a rod knock but isn't as loud as a knock. Randomly comes and goes only when engine is warm. Running 5w40 shell rotella t6. Been around since mid fall.
This first vid is what it first sounded like in fall. It rarely gets this loud, usually just a little noisy. It even disappeared for almost a full month at one time and this is my Daily.
https://youtu.be/kX6AmoaeemE
Then finally, the sound changed to this in early January but also still made the other sound at times. this was the last time I drove it before pulling the engine
https://youtu.be/G-jgLVIRQfI
I pulled the engine and pulled the pan. Found it to have been rebuilt by the PO. Rods and Mains at .020. I took the crank to shop and had it redone and put new correct size rod and main bearings in as the old ones were worn down to the brass. I figured the worn bearings were the cause of the engine knocks.
Put it back together. And drove it to college and back (15-20 miles). On the way home it started making the noise again and by the time I got home it was just as it was before (sounded like the first video).
Not sure what to do. There were no broken piston skirts when I rebuilt the bottom end, rod wrist pins and Pistons felt nice and tight, no play. And flex plate didn't appear to have any cracks. Any reason why all the old bearings were worn on one side. Any ideas as to the noise? Thanks.
It only does it at idle and disappears as RPMs rise. Sounds like a rod knock but isn't as loud as a knock. Randomly comes and goes only when engine is warm. Running 5w40 shell rotella t6. Been around since mid fall.
This first vid is what it first sounded like in fall. It rarely gets this loud, usually just a little noisy. It even disappeared for almost a full month at one time and this is my Daily.
https://youtu.be/kX6AmoaeemE
Then finally, the sound changed to this in early January but also still made the other sound at times. this was the last time I drove it before pulling the engine
https://youtu.be/G-jgLVIRQfI
I pulled the engine and pulled the pan. Found it to have been rebuilt by the PO. Rods and Mains at .020. I took the crank to shop and had it redone and put new correct size rod and main bearings in as the old ones were worn down to the brass. I figured the worn bearings were the cause of the engine knocks.
Put it back together. And drove it to college and back (15-20 miles). On the way home it started making the noise again and by the time I got home it was just as it was before (sounded like the first video).
Not sure what to do. There were no broken piston skirts when I rebuilt the bottom end, rod wrist pins and Pistons felt nice and tight, no play. And flex plate didn't appear to have any cracks. Any reason why all the old bearings were worn on one side. Any ideas as to the noise? Thanks.
