Crankshaft seal question

[bcjjones]

So just for clarification the rear main seal kit is for the crankshaft seal case? And the crankshaft seal is also replaced when the rear main seals are replaced also?

Fel-Pro BS40408-1 - Rear Main Seal Set | O'Reilly Auto Parts

That being the rear main seal kit

National 224460 - Oil Seal | O'Reilly Auto Parts

And that beaing what is behind the rear main seal

 

[Dsmkauai]

Rear main seal is the seal behind the flywheel/clutch. Crank seal is behind the crank pulley.

 

[bcjjones]

Is it common practice to replace the crankshaft seal and the rear main at the same time?

 

[ChiTownHussla]

if you are being meticulous yes

 

[bcjjones]

Well I guess my real question is what is the likelyhood of the crankshaft seal leaking? Is it more likely that just the rear main seals are leaking?

Car has 128k on it. I guess I'll know once the trans is off but as with all oil leaks, the origin isn't the easiest to find.

I've heard to replace the crank seal the oil pan needs to be removed which was done recently so I want to avoid that if possible.

 

[Dsmkauai]

I've had them both leak at separate times. Replacing both is a great idea if you don't mind the work. I did my last rear seal when I switched clutches and I did the front seal when I did the timing belt last, I also took the time since I was in there to replace most of the other seals so they are all fresh.

 

[jayson427]

Well I guess my real question is what is the likelyhood of the crankshaft seal leaking? Is it more likely that just the rear main seals are leaking?

Car has 128k on it. I guess I'll know once the trans is off but as with all oil leaks, the origin isn't the easiest to find.

I've heard to replace the crank seal the oil pan needs to be removed which was done recently so I want to avoid that if possible.

well the easiest way to see if you have a rear main seal leaking oil is to look into the clutch inspection cover and see if there is oil all splattered inside the bell housing. but if your crankshaft seal is weak and you replace the rear main gasket it could make the crankshaft seal leak right away or it may not. just recently i swore i had a rear main seal leaking but it turned out to be the oil pressure switch. degrease the block some what and let the engine run then shine a flashlight all around see what you find.

 

[Joethefallen23]

Is it common practice to replace the crankshaft seal and the rear main at the same time?

Not necessarily, Common practice is to do the crank seal with a timing belt job and the rear main seal with a clutch job (or any time you have the trans off for that matter). All of which is assuming the seals have plenty of miles on them.

 

[bcjjones]

Well I am a Tech here at a local dealership and have been a light duty mechanic for several years. I'm aware of how to find an oil leak, just not always the easiest.

So I'm dropping my trans once again to replace the clutch and putting an oem tob in also. With 128k on the motor, what seals would y'all reccpmend replacing? It's obvious at least the rear main is leaking, as I have oil in the bell housing.

 

[Dsmkauai]

I would do them all, just buy a good oem full motor seal kit and start replacing them as you do certain mods or maintenance to your car.

 

[bcjjones]

Okay sounds good, but what specifically in relation to dropping the trans?

 

[Dsmkauai]

Probably just the rear main and maybe the axle seals when doing a clutch job.

 

[bcjjones]

So I am confused or isn't there a crank seal behind the rear main?

 

[Dsmkauai]

Same thing rear main seal = crank seal. The other paper gasket is for the rear main seal retainer which doesn't have to be replaced when doing just the rear main seal. If you want to do the retainer gasket the oil pan has to come off.
http://www.mitsubishiparts.com/oe_parts_catalog.html?Year=&make=&catalogid=1

 

[jayson427]

i would read up on replacing the rear main seal as alot of people replace it incorrectly. there is a pic by pic thread that shows everything. iv seen alot of threads where they replace it and its worse then before just a heads up.

 

[bcjjones]

Okay great info thank y'all. Leads me to yet another question though. Would it be wise to replace the retainer gasket or are those not a common problem for leaks?

 

[Dsmkauai]

It won't hurt to since you'll be in there, but like I said the oil pan has to come off. So that means you'll be doing the oil pan gasket/grey rtv too.

 

[bcjjones]

Well I dont mind the extra work, and doing the oil pan again. Only if the retainer gasket is a common leak though?

Thanks for all the responses!

 

[pauleyman]

How do you guys intend to replace the rear seal without removing the housing considering the seal is installed from the inside? I done them and did not take the pan off. The housing itself is part of the flange the pan seals to so I resealed that part from the top side. If you wanted one continuous bead that cured at the same time then yes, you'll have to redo the oil pan.

 

[Dsmkauai]

Seal comes right out the center without housing removed pretty easy actually then press back in. I have also done the housing gasket without taking the pan off. I only suggested it so the job was done the right way and no chance of a leak later on.

 

[pauleyman]

It might be different for 2g. I've only changed 1g and if memory serves its from the inside.
Just looked it up and it's 6 bolt that is on the inside and requires housing removal.

 

[Dsmkauai]

Yes correct sorry I should have specified the gen. 1g (6bolt) housing has to be removed, 1g or 2g (7bolt) does not.