O.K., heres the deal. I'm tired of babying my Jeep around to keep the rattling rods from blowing a hole in the block.

Has anyone ever replaced only the mains and rod bearings in a 4.0 engine? I know, I'm supposed to turn the crank, but I have done this on farm tractors and road tractors (in-frame rebuilds) and they kept going for years.

 

Won't know til you see the bearings and crank.

How long has it been doing this?

 

I've been driving it like this for a year. Has 40 psi oil pressure on start up. Drops to 10 psi after oil gets hot in about 5 miles. When the engine experiences no-load, like between shifts it gives off a very noticeable rattle. It's never given what I call a classic "rod-knock". Sounds like all the rods are rattling in unison.


I originally thought it might be the lifters, but an engine man said "its on it's way out", that is your bottom end.

 

Where did my reply go?? Here it is again. I have been driving the Jeep like this for over a year. It has 40psi oil pressure on start up, drops to 10 when oil gets hot. When the engine is in no-load condition like between shifts it gives off a very noticeable rattle. It does not smoke or have what I called a rod-knock.

 

you sure it's not just spark knocking?

have you verified the oil pressure with a mechanical guage ? you won't get a years worth of driving out of a bad bearing (or 8). a friend of mine changed just the bearings in his jeep. it had low oil pressure and a noticeable tick at hot idle. no damage to the crank so he just replaced all the bearings with std size.

 

I'm doubting it's the bearings. They don't last that long once they begin making noise.

Auto trans? If so, flexplate bolts loose?