Anybody know whats involved in changing rod bearings, does the engine need to be pulled out or can it be done by removing the oil pan?

Anybody know how much a mechanic would charge?

 

I changed them in my old CJ5 6 banger by just pulling the pan. Of course I have put a number of engines together so it really wasn't a big deal. Be sure you replace the oil pump and the rear main seal while you are at it

I don't have a clue what somebody might charge for that.

 

so can they be changed without removing the engine? Can you just pull the pan and change them out?

 

I have done this several times on 4 liters and if you are in there you might as well throw some mains in it too. You can get to everything when you drop the pan. I paid less than 100 in parts at AutoZone, Advance auto and some other shops wanted almost double that so it pays to shop around. Don't know what a shop would charge to install, probably a couple hundered.

 

this a TJ? XJ? auto?

 

It is in a 99 grand cherokee WJ, auto

 

the motor was sludged up to the point that i had to dump motor flush into the spark plugs to get the engine to free up enough to crank. I have flushed the motor out and I believe I have taken care of the sludge problem for the most part. I thought rod bearings were shot when the oil pressure drops at idle......my oil pressure drops to 5-10psi at idle and goes to 40 when I rev it up. Maybe I am wrong at diagnosiing the problem. I pulled the valve cover off and the rockers and springs look good.

 

had 2 4.0's around that same year and both ran fine but sounded like a bad rod knock, turned out it was torque converter to flexplate bolts were backing out and hitting the tranny case. Pull the inspection cover before you buy parts...

 

you killed your oil pressure sending unit with the motor flush or it still has sludge in it...common problem, replace sending unit

 

wouldn't hurt to drop the pan and have a look and maybe replace the seals, and oil pump. I did it on mine back before the 350 swap. I'm pretty sure it is a 2 piece rear main seal.

 

In my experience 5-10 psi at idle and 40 psi revved is normal for some engines. Is the bottom end making noise?

 

yes, there is some knocking going on and it sounds like its in the bottom of the motor.

 

pull that inspection cover off before you buy parts, as a former jeep tech, I've seen it before not only on some of my trucks...