Scary YJ engine noise

[TRevs]

I had an oil leak in my 95 YJ so I tackled the rear main seal and oil pan gasket. Never done a RMS but since my LJ just developed a similar leak I decided to go for it.

Things went slowly but I the only trouble I had was inserting the new upper half; it was very tight and I ruined one. I reinstalled the oil pan and spark plugs last night (I had removed them so it would be easier to turn the crankshaft when replacing the rear main seal), added oil to the proper level and started the engine.

Immediately there was a new noise, sort of a mid-pitch whine. I listened for about 30 seconds before shutting it off. I couldn’t tell if it was coming from the top or bottom. I let it sit for a few minutes started it again, thinking that maybe the oil pump was just dry, It made the same noise but after a few more seconds the whine diminished a bit and I thought I heard a light tapping/clicking noise. As i was under the jeep listening, I saw a few wisps of smoke around the back of the engine/front of the transmission, so I shut it off again.

So I’m worried but also glad it isn’t the LJ. Does anyone have any possible explanations for the noise? Could this be something temporary and benign, like a little excess RTV? Should I drop the oil pan again and inspect the crankshaft?

 

[Rickyd]

Does it have oil pressure? Is the rear main cap torqued? Excess sealant get onto the bearing?Pickup tube in place?

 

[TRevs]

I didn’t look at the oil pressure gauge when it was running but I can do that.

I was careful to apply the 3mm bead of RTV only where indicated on the bearing cap, but I saw a tiny bit squeeze out after installing the cap; I imagine some could have worked its way around the shaft as well, but I can’t imagine it would be much since inused it sparingly.

In addition to removing cap #7, I loosened #4, 5, & 6 in an effort to lower the crank a hair and get just a bit more clearance to insert the new upper seal, which was very snug. I don’t think it helped, but I did torque all 4 caps incrementally like 40 ->70 ->80. I tapped each cap lightly with a plastic hammer to seat the cap and get the bolts hand tight before using a wrench.

 

[TRevs]

The oil pickup was undisturbed. I saw a bit of sludge on the screen but it seemed minimal to me

 

[TRevs]

I cranked it up this afternoon. Oil pressure gauge went up promptly. The sound was less pronounced than yesterday; it almost sounded normal but still a faint metallic whine. Seems more audible near the front of the engine.

Maybe i’m just not remembering what it sounded like before the repair.

 

[Rickyd]

Try removing the accessory belt? That will eliminate a lot of noises

 

[TRevs]

Here’s some audio from the second start

 

[TRevs]

Welp i started it after letting it sit for a couple days and it sounds normal now.