check these bearing journals please...

I'm doing my rear main, joy of joys, and was concerned about what I saw. I decided to pull the next cap and it looked worse as far as color is concerned, but I don't know if this is normal or not. Opinions?

They are not good,but also not horrible,it would depend on the actual mileage more than anything.Also might want to look at the rods.Might be able to just have all the journals polished if they are in spec.

Yeah, let's see the rod bearings, too.

Thanks for the response from both of you. I'll have to wait until tomorrow to pull a rod cap, but I'll get a picture up when I do. Just a little more background, this is from a '92 with approx 165,000 indicated miles, but I'm sure it's at least a little higher if not a lot higher as it had 31" tires installed with the old speedo gear when I bought it a few months ago. This is my daily driver, but it is not driven hard at all. I prefer 5w30 synthetic oil, but would another type and weight possibly help to slow the wear that is already taking place? And I've done a lot of reading about how these 4.0's need higher zinc content because of the flat tappets, is that something that might help with this crank bearings as well? Thanks for your time to anyone who can help.

The bearings are scored from dirt in the oil. This comes back to oil filter quality and oil change frequency.

What's lurking at the bottom of the oil pan near the drain plug? Lots of gray material?

4Doors said:

I prefer 5w30 synthetic oil, but would another type and weight possibly help to slow the wear that is already taking place?

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Your sig says you are in Fla, I feel 5W30 is too thin for use on a high Milage XJ in a hot weather state like Fla, I would go with Mobil one 10W40 or 15W50. The Jeep owners manual calls for 10W30.
I am in NY & use M1 10W40 winter & 15W50 summer.

cruiser54 said:

Yeah, let's see the rod bearings, too.

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Here you go...

winterbeater said:

The bearings are scored from dirt in the oil. This comes back to oil filter quality and oil change frequency.

Click to expand...

That's always a risk with an older used vehicle, but I wasn't going to be too picky for $900. It runs smooth as silk and has good oil pressure.

As for the bottom of the oil pan, there was grime but no metal shavings.

I may go ahead and bump my oil to 10w30 if it will help slow wear.

I drive this XJ with a light foot so if it doesn't look like it's going to die right away, I'll probably leave it alone for the time being. My father-in-law and I are thinking about buying a beater together so he can get the trans/t-case for his MJ project and I'll take the engine and rear axle. I'd do a full rebuild on the engine before swapping it.

I wouldn't sweat it too much. Those are just bearings doing their job. Could be better, but they're not into the base. Bearings are designed (I think it's called embeddability?) to sustain those little pockmarks and scratches without damaging the crank.

Ok that does help me feel better, because the crank looked perfect everywhere. This is the second Jeep rear main I've done but I feel much more knowledgeable this time around. This isn't an especially fun job to do, but it is pretty rewarding. Thanks everyone for your input!

You're good to go for now. The rod bearings I took out of my 88 make yours look like brand new.