So just a little background first: It's a 91 Cherokee Limited, it's got 277xxx miles on it but the engine itself has around 150xxx. I bought it knowing the water pump needed to be replaced which caused it to make some terrible screeching noises, other than that it ran great. Fast forward: I replaced the water pump with a brand new Bosch water pump, replaced the serpentine belt, thermometer, and did an oil change along with new coolant. We also did the the front brakes, so my cousin and I put it up on jack stands and replaced the pads and rotors. Then we started it up while it was on the stands and that's when it started with this sound. He thinks it something like rod knock, piston slap, or something similar. But I had no problems with this sound before so I wouldn't think it would all of a sudden have piston slap or something, especially this loud. And it stops sometimes and gets worse when I go over bumps or turn sharp. I just wanted to get some ideas on what to look for, thanks guys!

 

Was the water pump locked up, did it over heat? I assume you have the correct amount of oil in it. Long shot, what kind of oil filter did you put on it?

 

Seems kinda random. Maybe a weak oil pump or clogged oil pick up tube.

 

Brand new Wix oil filter with six quarts of Castrol 10w-30 with a little seafoam. The rod and wheel on the original water pump had a lot of play in it which also ate up the serpentine belt. It's really throwing me for a loop, I was wondering if maybe when we put it up on the jack stands and started it, if it could have caused a mount of something to break or become loosened, I know that's a long shot but I can't thinking of anything else that could cause a sound like that out of thin air. Oh I have good oil pressure too.

 

Remove belt and start see if knock still present if not inspect all things that belt rotated . Only run for a few seconds as not to overheat engine.

 

I'll try that as soon as I can. I'm currently laid up after my last dentist visit. Is it a possibility that we could have bent, broke, or moved something out of place when we put it up on jack stands?

 

Check Flex plate. Could have lose bolts or a crack on it somewhere. And be sure to inspect it thoughouly. Cruiser54 on here recomends doing this as maintenance for all these jeeps.

Read this thread l
V

https://www.cherokeeforum.com/f51/ho...ocking-125547/

 

Depends were stands were put ...very dought full if they were under axle or frame rails...

 

I didn't think so but im grasping at straws. The noise I'm hearing sounds similar to the flex plate knock but a lot louder and is isn't always consistent. Hopefully this Saturday I'll be able to get a video of the sound to help you guys out.

 

Alright guys, I haven't been able to work on the Jeep but I found a video that is pretty close to what I'm hearing: So I have a question, the sound isn't there all the time, so would that mean that the flexplate bolts are just loose? I'm afraid of the flexplate being cracked because I don't have tools to drop the tranmission. Thanks for the help guys

 

So I was able to get under the Jeep today finally and sure enough 2 of the flexplate bolts were loose so I tightened them back up and now it's as quiet as a mouse. Thanks guys