2.5 engine noise (with videos)

[Tim_with_the_tj]

Before

After

Oil pan findings

The after video was when the engine still had the old filter, ATF, and fresh 10w30 oil (before I removed and cleaned the oil pan). Now the engine sounds even better IMO. She will probably run forever now. Haha.

 

[Tim_with_the_tj]

So cleaning it out, old school style, with 1 quart of tranny fluid "fixed" the rattle? Or do you believe it was a replacement part? Correct me if Im wrong, but you didn't do anything up top except check it and replace the valve cover, right?

Heck, if all it took was a thorough removal of gunk, then I'd be shocked. I'm due for an old change I'd do the same but I tried mystery motor oil years ago and I didn't do shit. I will say that my TJ, after a long drive, (ei. last night for example) it's often relatively quiet in comparison to when it starts and sits for approx 3 min, when I begin to hear the rattle.

Ya gotta videos of the before and after. That's wild if its just a matter cleaning.

Yep, she just needed some love. I did not replace any parts in the top end. I’d recommend trying the 1 qt of ATF with some cheap oil and run it for a day before doing your oil change. It’s cheap and easy. Worth a shot. I think I just got lucky on this engine, though.

 

[fourpointzero]

For sure, much quieter. Good shyt!

I wont be as lucky, though. I listened again to the audio of your video clips and def misheard what I thought I originally did. Mine is a lower toned and more audible at the lowest point of the engine. Been that way for years. Over 67k since owning it and haven't had a problem. I'll keep going till it doesnt, but doubt it'll fail. Im almost at 200k and keep up w maintenance and servicing as if it was anyone's cherished ride.

 

[Tim_with_the_tj]

in the video from the bottom it almost looks like your fan blade is wobbling .

Meant to tag you and tell you I found 2 of the 4 fan bolts so loose I took them off with my fingertips. Lol

For sure, much quieter. Good shyt!

I wont be as lucky, though. I listened again to the audio of your video clips and def misheard what I thought I originally did. Mine is a lower toned and more audible at the lowest point of the engine. Been that way for years. Over 67k since owning it and haven't had a problem. I'll keep going till it doesnt, but doubt it'll fail. Im almost at 200k and keep up w maintenance and servicing as if it was anyone's cherished ride.

Well, I wish your engine the best of luck in the long run. For what it’s worth mine was loudest at the front of the oil pan, under the timing cover area.

 

[Tim_with_the_tj]

….aaaaand she’s loud again today. Must be a sticking lifter(s)?

If it were rod or crank bearings I feel like it would’ve never quieted down like it did. The mystery continues.

 

[Tim_with_the_tj]

SOLVED IT!

Short version: It was an incorrectly installed harmonic balancer the whole time, causing the engine noise/knocking! The old balancer didn’t even look like it failed, but what I didn’t realize was someone had not seated it onto the crank fully. They ran it onto the crank with a bolt and the bolt bottoms out in the crank before the harmonic balancer is fully seated (looks correct and torques to 80 lb ft but is not correctly installed).

If you have knocking, check that your balancer is fully seated onto the crank using an install tool. You can rent one like I did. Basically free.

The details: I replaced the balancer when I removed the timing cover to inspect the timing chain set, even though the balancer didn’t look bad. I figured why not.

I installed the new harmonic balancer with a proper install tool. At this time I also added ATF mixed with fresh engine oil to the engine. Upon cranking the Jeep the motor was quiet! I thought the ATF had freed up a lifter. I drained the oil mix, installed a new filter, and fresh oil. The Jeep was still quiet.

Later I noticed something. The crank bolt washer (fat washer) was loose enough to spin by hand, even though the crank bolt was torqued to 80 lb ft. The bolt was bottomed out in the crank.

I decided instead of adding washers I would slide the balancer out slightly then re-torque it allowing the bolt to seat the balancer. So I did that (mistake)

Next day I replaced the thermostat and then started up the vehicle. It clattered on startup and was knocking/loud again to my surprise. I thought damn maybe a lifter got stuck again. Then it dawned on me. Something HAD changed. I messed with that harmonic balancer.

Today I removed the balancer to measure it compared to the old one, thinking the snout must be different in length somehow. It was exactly the same as the old one. Hmmm. So I asked myself when was this engine running quietly? It was when I installed the new balancer with the install tool and FULLY seated it against the crank. So I reinstalled the new balancer with the install tool and fully seated it. I used two hardened washers as spacers on the crank bolt/washer so the bolt wouldn’t bottom out too soon. Cranked her up and she’s quiet again!

Problem solved and some lessons learned. Someone during previous ownership had the balancer installed incorrectly and it was causing the knocking noise the whole time.

Hoping this will help someone else one day