Ok, so here I go again. I have a '94 XJ 4.0L 2wd 5-spd, 3"lift. Just noticed I had a crack in the exhaust manifold, but I saw another thread that said you could weld it. But, I have to change the rear main oil seal soon, I've seen write-ups for this. My question is, that I have a lower end knock, sounds closer to the firewall. But, I have a hynes manual, and I was looking up the rod and main bearing. The manual says there is some kind of color code to the bearing size? Is this true, or can I just go down to the part store and get some standard bearings? I'm planing on doing this with the engine in the truck, does anyone have any advice to help me make sure I don't F the crank up, or motor after? I've done bearings before, usaully not a big deal, time consuming, but not to bad. But, I'm alittle cautous because the manual was saying all this weird stuff, about how all the bearing are different sizes? Just wanted to get your guys opion on it. And any advice.

Thanks,
J

 

How long has it been knocking? Check your flexplate first before you pull off the main and rod caps. A cracked or broken flexplate will sound just like a rod knock. Pull the inspection plate off the trans and look for cracks. They may be very small and hard to see, but if there are any it will usually lead to complete seperation around the bolts holding it to the crank.

 

Knocks been since I bought it. I did do the entire clutch about 2-3 months ago. New everything. I'm pretty sure it's a bearing, or rod.

 

Well if you replaced the clutch it's not the flexplate.. You have a flywheel not a flexplate. As for rod bearings you might be able to buy just one but I have always bought the set never a single.

 

How long have you had the Jeep. We know at least 3 months.

 

I've had the XJ for almost a year now. But, I put about 220 miles on it a week. The knock isn't so bad that I think it's going to die. I just want to stop this before it gets any worse. I'll probably pick up the set, and just change them all. I'm going to do a compression test also, even though I really don't want to take the head off. I figure doing the rod bearings, and cleaning out the sludge in the oi pan, made a new oil pick up, if it's all sludged up, and rear main seal should do the trick. Any other advice?

And I don't drive it like a grandma, but I don't beat the p*** out of it either. I drive like an XJ should be....

Thanks,
J

 

Any other good advice when doing rod bearings or rear main seals? And how do I know, before I rip everything apart, if I have a 1 piece or 2 piece seal?

 

Replacing bearings on a high milage engine without reconditioning the rods/crank journals is a waste...and if you have rod knock there is a chance you could have a nicked crank...Leave it alone unless you tend to rebuild it.

 

yeah, the motor has 202,XXX on it. I'm starting to think that same thing. It still has great power. I still have to do the rear main though. When I do, I'll just clean all sludge out. What does it mean when you say "spin a bearing"?

 

it means that the rod/crank has struck the bearing causing it to spin in its journal....

 

Thanks Guys!