FlyingXJ Posted October 5, 2021 Share Posted October 5, 2021 So was driving to work when this noise popped up when driving was a bit loud at first at idle and driving. Put got quieter later in the day and can be heard at idle and low rpm but whent away when above 2,000 rpm. I ask around and I got so many different responses ranging from piston slap, flexplate/flexplate bolts, sticky lifters, timing chain to water pump bearing. The only one I'm ruling out is the piston slap since I watched a couple of videos of 4.0l with piston slap and it was a lot louder then my nosie (then again I could be wrong). 20211002_114429_1_1.mp4 Link to comment Share on other sites More sharing options...
Pete M Posted October 5, 2021 Share Posted October 5, 2021 do you have an engine stethoscope? Link to comment Share on other sites More sharing options...
Eagle Posted October 5, 2021 Share Posted October 5, 2021 Video won't play for me. What's your oil pressure? What oil do you use, and what brand of oil filter? Link to comment Share on other sites More sharing options...
Muncher Posted October 5, 2021 Share Posted October 5, 2021 Make sure it's not your wheel lol Link to comment Share on other sites More sharing options...
FlyingXJ Posted October 6, 2021 Author Share Posted October 6, 2021 @Pete M sort of one of the guys at our shop let me borrow his and even then we came up with different opinions of where it was coming from. I heard more noise coming from between the front of the bell housing and the rear of the engine, while he says the nosie is coming from the front and echoing throughout the pan toward the rear. @Eagle my oil pressure at cold start stays at 40psi -60psi when going down the road. When it warms up i would say by the stock oil pressure guage 20-30 psi when warm and 60 psi when going down the road. As for the oil I don't know but I am going to change the oil to the stock oil it is suppose to have, the filter is a normal autozone filter that fits it. Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 6, 2021 Share Posted October 6, 2021 Bad lifter Link to comment Share on other sites More sharing options...
cruiser54 Posted October 6, 2021 Share Posted October 6, 2021 check the flexplate bolts first. https://www.cherokeeforum.com/f51/how-fix-flexplate-knocking-125547/ Link to comment Share on other sites More sharing options...
FlyingXJ Posted October 6, 2021 Author Share Posted October 6, 2021 @cruiser54 what is the torque specs the flexplate bolts are suppose to be at? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 6, 2021 Share Posted October 6, 2021 Tight!! The factory torque spec was too low. Remove the bolts one at a time, wire wheel the threads, re-install with LocTite tight as you can get em with a 15mm wrench. Link to comment Share on other sites More sharing options...
FlyingXJ Posted October 11, 2021 Author Share Posted October 11, 2021 Update: So took it to a buddy of mine that had a lift, and checked the flexplate and flexplate bolts. Flexplate was good no crakes, the bolts where all in and I'm glad I decided to check them while they where all in they weren't exactly tight. So I took them out cleaned them, put lock tight on them and tighten as hard as I could. So after that I decided that since it was up in the air to change the oil and filter. Once I did and started it up the noise was very quiet and now took on the noise of a tick when at idle and went away once warmed up or at higher revs. Which me and buddy concluded that it was most likely that the noise all along was a lifter(or lifters) that went bad. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 11, 2021 Share Posted October 11, 2021 What brand of oil filter? Link to comment Share on other sites More sharing options...
FlyingXJ Posted October 11, 2021 Author Share Posted October 11, 2021 For it just has a STP filter. Also any one know wheres a good place to buy the head bolts for my year of jeep? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 11, 2021 Share Posted October 11, 2021 STP are junk filters. Use Wix or NAPA Gold. why do you need head bolts? Link to comment Share on other sites More sharing options...
FlyingXJ Posted October 11, 2021 Author Share Posted October 11, 2021 Ok ill change it, as for the headbolts aren't you supposed to change them when taking the head off? Or can you resue them? Link to comment Share on other sites More sharing options...
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