2 piece rear main seal advice

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
Guys I think ive got a leak from the rear main seal, not sure but going to pull the dust cover and look around. I bought the good Felpro blue gaskets. Ive read some stuff about how they never really seal up. Will I be wasting my time doing this or should I give it a go. Ive heard all kinds of things from rotating the halves of the gaskets so the ends don't mate up exactly with the block/pan surface, to using a dab of silicone on the edges, etc. Any advice would be good. Thanks
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,388
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
I've heard all the things you've heard. The only suggestion I can offer is to be sure that it's not the rear portion of the oil pan seal because those like to leak sometimes, plus they look and act similarly when they leak. The only comfort I can offer you is that at least it's not like changing the rear main seal on a Gen III small block.
 

74 Shortbed

Full Access Member
Joined
Aug 12, 2013
Posts
6,306
Reaction score
1,413
Location
*
First Name
*
Truck Year
*
Truck Model
*
Engine Size
*
IF the rear main seal is leaking you'll have to drop the pan and the rear cap, rotate the block half out, it can be a PITA sometimes but it will come out, reverse for installation just make sure the lip faces inward same for the cap, DO NOT use silicone on the ends it'll be all over the crank, you can use a dab of gasket cement but you don't need anything for them to seal, re torque the cap and put the pan back on and you're done..
 

87scotty

Full Access Member
Joined
Oct 8, 2015
Posts
1,079
Reaction score
306
Location
Central il
First Name
Andrew
Truck Year
1987
Truck Model
V20
Engine Size
5.7 for now
And from what ive heard... So take it as a grain of salt but usually when rear main starts leakin your do for a rebuild. Do to crank thrust! Like i said idk if i belive it but makes since if its sliding back and forth taking out seals
 

74 Shortbed

Full Access Member
Joined
Aug 12, 2013
Posts
6,306
Reaction score
1,413
Location
*
First Name
*
Truck Year
*
Truck Model
*
Engine Size
*
A seal will fail from sitting too long and dries up and sticks to the crank, when you start it up it grabs the seal and ruins it, also excessive heat will harden the seal and make it leak, badly worn main bearings let's the crank move around and will cause the seal to leak, a bad thrust will allow more end play but won't cause a seal to leak
 

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
Thanks for the insight. Im not worried about it needing rebuilt, I may get to this today
 

Latest posts

Forum statistics

Threads
43,937
Posts
946,051
Members
35,982
Latest member
jake26104
Top