Rick_Vor

iTrader: (36)

I've ran into a bunch of posts that recommend installing the new style OEM rear main seal backwards on boosted application.

I put a new OEM rear main seal the recommend way (this side out markings facing out) on my forged 370 when I assembled it. It took quite a few tries to install if so I may have just jacked it up suring the install. It's got a steady drip leak at idle (18" vacuum) so I need to replace it before I put it under any boost. I thought I'd ask before I start dropping my 4L80E and transfer case. It's a solid 8-10 hour job so I'd rather not have to do it again.

By the way, I'm running 5/8" hose from each valve cover to a catch can so I haven't had any issues with a boosted crankcase focing oil out the seal on the original motor.

Also, any preference for OEM or Felpro?

Rick

FasTimeSS

iTrader: (47)

Curious

FMX05

iTrader: (3)

I've heard both ways as well. I remember seeing an engine builder say they have better luck installing it backwards. I put mine in as gm intended. So far my 390 hasn't seen any boost but its been in nearly a year with no leaks.

cleonard

what about when installing oil pan and front cover at same time.

BKnBLK05

Been through this put it in right,make sure it's tap all the way to the bottom of the cover...you shoud be fine

pwrtrip75

iTrader: (8)

lol..

cleonard

jokes on me i guess. what i meant was what is torque sequence when having all of them off.

FMX05

iTrader: (3)

If I remember correctly this is what gets people. When they do it "by the book" the book is telling them how to install the old seal. I think the old seal had to be installed to a certain depth but not bottomed out. The new one likes to be seated all the way in.


Just be careful not to force it too much. I didn't have a piece of pipe big enough to go that route so I used a small rubber mallet, a block of wood, and my fingers. You should be able to feel when it is evenly seated.