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Rear Main Seal Catastrophic Failure - Rebuilding Engine

C

CNorell145

New member
So, my RMS decided to give out completely as I was going down the road yesterday. By the time the idiot light came on, it was already too late - the damage had been done. The oil was leaking in a steady stream.

The engine now tries to die whenever I slow down - dropping to 150 - 200 RPM. I believe this is being caused by damage done to the journal bearings, and in turn to the crankshaft. That being said, I am going to have to replace the whole lot of it before I can drive the car again.

My question to you guys is this:

Is there anything else I should replace while I have the engine apart? The car is at 102,000 miles.

Also, are there any performance mods you guys can think of doing to the engine while I have it apart? I was thinking about stroking the crank, shouldn't be too much more work since I already likely have to replace it.

Any other advice/potential diagnosis would be appreciated.
 


Find yourself a used motor for $400-700 and drop it in. Not worth rebuilding the bottom end on these cars unless you have the proper ($$) machine shop work done to it. If you do the bottom end yourself you may very likely end up with a 100-mile motor before it eats itself again even with all new parts.
 
Another question -

If I wanted to just replace the RMS and the crankshaft... Can this be done from underneath the car, or would the whole engine have to be pulled? Has anyone attempted this?

Thanks in advance
 
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You have to pull the whole motor as the block has to be align bored and checked over before installing new main bearings.
 
CNorell145 said:
Another question -

If I wanted to just replace the RMS and the crankshaft... Can this be done from underneath the car, our would the whole engine have to be pulled? Has anyone attempted this?

Thanks in advance
Click to expand...
Chances are that if the engine was starved for oil, the crankshaft will not be the ONLY damage, which means the entire engine assembly needs to be disassembled, and inspected, and worn parts be replaced, but rebuilding an engine is not just replacing parts, it involves enough to write an entire book, so, if your not experienced at rebuilding engines, don't do it.
 
the only way to "rebuild" a 3800 is with a good motor....

once you tear it apart your going to find that youll need a crank, cam, lifters, etc, etc. by the time you hunt down parts your spending more than a good used motor.

any aftermarket crank you buy to replace your destroyed stocker is likely a welded and reground crank...and those snap and destroy lots of expensive parts...i know

and then once you get a good used engine to start your "rebuild" youll find that all you need to do is re gasket the motor and drop it in.

just trying to spread some wisdom here....
 


^ What he said.. along with everyone else.

These motors are not worth rebuilding. There used to be a Swan stroker setup that raised the displacement to 4.2L. From what I've read the gains were not worth the price on the kit... plus I don't think they are available anymore. But yeah if you pull the crank for new bearings you will need to align bore the journals. Unless you have a bunch of machine shops at your disposal... forget about it.
 
Just to chime in..... (probably shouldn't try this)...When I blew motor #2 I pulled out a running junk yard L36. It ran fine before I pulled it but I tore it down anyway. I just didn't like how the bearings looked so I did new rod bearings, new mains and new rings. I had the service manual alongside me and followed all limitations. The motor is by no means blue printed, but I hit 3500 miles today. Motor is top swapped and the only modification to the long block is 105 springs. I am very happy with my ticking time bomb so far.

Sent from my SPH-L720 using Tapatalk
 
FWIW and James.. please correct me if you think I'm wrong, but likely the RMS didn't go. It's more likely the rear cover gasket or an oil pressure sender to dump that kind of oil. The RMS wouldn't have that kind of pressure and supply to kill a motor that fast.

Plus.. Every rear engine cover gasket I've seen, needed to be redone. I don't think I've actually found a RMS leaking. If you grab a new motor, rear engine cover is a must, not a maybe.
 


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