91GTRI

I think I have a leaking rear main seal, how hard is this to replace? I've noticed little puddles in my driveway the last week or so, and jacked the car up yesterday to look. I changed the oil, wiped everything down then started it up, and can see a little trickle running down the metal cover that covers the flywheel on the bellhousing. I have not gotten a mirror yet, and checked the rear intake seal to make sure it is not that. My question is this, I've heard that if the pcv valve or some screen gets clogged it can cause the seal to blow. Is this true? If so, where is this screen located? I know the pcv is under the intake plenumn, can you change this with out removing the plenumn? Any help would be appreciated. What has to be done to replace the seal? drop the pan? drop the tranny?

TheGmKiller331

Oh you are going to have fun!

Are you a descent mechanic?Can you do descent sized jobs?You are most likely going to need to drop the tranny.

Thats how i do it it seems like a lot of work but removing it gets you right there and its easily fixed.The only problem is that this will take about 2-3 hours if youre good.

Wait until you see what all that work was for.Less than a nickel worth of rubber.LOL

619socalstang

pcv can be change by pulling it out anf inserting the new nohting alse involved. in a 91 you can not just drop the pan have to pull the motor or lift it to do so but that does not matter because to replace the rear main just remove the tranny and pull the old seal out and put the new one in, be sure to press it in evenly and completely, check crank for burns and such.

TheGmKiller331

Well i thought that lifting the motor up to clear the double hump pan was common sense but yes you should lift it.Its ewasier to pull the tranny and then jack the motor up thjat to pull the motor.If it was a carbed setup like mine 30 minutes to have it out by myself.But you have EFI so theres lots **** to tag and disconnect.

91GTRI

when dropping the tranny do you disconnect the bellhousing from the motor first? I've never taken a manual tranny out, always automatics. Also, anyone have an answer about the pvc or the screen(?) that gets plugged. One thing I noticed was a little condensation on the inside of the oil filler cap. It was not milky or anything, but there were some water droplets. I've never noticed it before.

TheGmKiller331

That sounds like condensation.If its not milky then youre ok.


As far as the manual tranny goes remove it like any other tranny.The easiest is in one peice.

roundman

make damn sure it's the rear main seal before you go changing it. it could be a valve cover gasket leak or intake gasket leak that lets oil run down the back of the motor and make you think it is a rear main seal. pull the bottom inspection cover on the bellhousing and look for oil inside the bellhousing and on the flywheel and clutch, if there isn't any here, then it is not the rear main seal leaking. you don't have to pull or move the motor to change it, just drop the tranny and bellhousing, then remove the clutch and flywheel to get access to the seal. the PCV valve just plugs into a grommet on the back left side of the block near the passenger side head. a large hose leads from it to the connection on the bottom of the intake upper, but you don't have to remove it to change the PCV valve. I don't know about any screen that can plug and cause the seal to blow. install a new PCV valve and make sure the hose from it to the intake isn't plugged up and you will not have any pressure build-up in the crankcase high enough to blow the seal unless the rings are really shot on the pistons. I changed my rear main seal when I installed my racing tranny at 108,000 miles just on general principles because I had the tranny out but the seal was still working just fine, so make sure it is the seal before you do a lot of work for nothing!