305 rear seal

[Buddy]

not even sure this is my problem but I have an oil leack i cant seem to find. It is dripping down from my starter area. I have already changed my oil pan gasket (this is what I thought it was) I have done that on twice, I cleaned the entire area and i am 100 % sure it is not leaking from there. I have also changed my valve pan gasket so i know it's not them. I also notice small drip marks on my felx plate cover. my question is how hard is this going to be to change. I know that my crank is the skinny one that sticks out and towards the back. some one told me I needed to know that first. so how do I go about changing this seal, is it a big job???

[onelow84]

valve cover maybe too....

[Buddy]

anybody else???

[bake74]

    The "crank seal" is most commonly refered to as the rear main seal.  You have to remove transmission and than you can access it, not hard once you get to this point.  You said you checked the oil pan gasket and the valve cover gaskets are new, are you positive it is not coming from the back corner of the valve cover ?  I would make sure before going to all that work.
     The other thing to check is when you get trans out make sure it is not from trans.   Tom

[Buddy]

what and where would it be coming from on the trans? is there anything i should replace when I have that off as I am 100 % it has to be the main seal i have checked everything else. What do i have to do to get the rear seal out

[Grim 82]

There are two styles of rear main seal. Newer motors use a 1 piece rear main that has to be installed over the end of the crank. To do this the motor must be split from the trans and the flex plate removed.
On the older more common motors in these trucks the rear main is in two halves, and is accessed by removing the oil pan and removing the rear main bearing cap.
Also check the top of the bellhousing area for oil. The back of the intake, dist, or oil pressure sending unit can leak there and drip down to the bottom.

[Grim 82]

http://forum.73-87chevytrucks.com/smforum/index.php?topic=3950.0

[Buddy]

ha ha dont get much better of an example on how to do it than that, thanks alot... I just not 100% that is where it is coming from. the oil on the bottom of the starter has me guessing where the leak is. I am leaning more towards the valve cover gaskets again. I dont see any oil coming from the bottom of the bell housing cover and i would think thats where it would leak from aftering seeing your pictures...again thanks alot.

[Lt.Del]

Those pics look mighty familiar  

Buddy, what year is your engine?  It may be a two- piece (like mine) or a one-piece rear main seal. As mentioned earlier, a one-piece is much more extensive since the trans must be separated from the engine.

[acefoxx]

Just another idea to look at. I had an oil leak that I had a hard time pinning down. It was my mech fuel pump gasket. As you drive it blows it back all the way to the starter. I had a broken bolt on my blockoff plate so I had to pull the engine to fix it. Other then that I would put my money on the rear seal or the real cross seal of the intake.

[Buddy]

ok here what I found out, got home looked everywhere again for a leak, took the bell housing cover off etc... no oil. I was like what the heck where is this oil coming from. so I backed the truck out of the garage a little so the exhaust was out side. I started the truck up crawled under neath and just waited and waited and waited nothing happened. So I crawled back out wiped everything down and did it all again than i seen the smallest of drip at the very back of the passenger side valve cover ....... a very tiny tiny drip. I found the leak. I just replaced the oil the other day so i couldn't see the oil coming doen the side of the block. I do know one thing I am done with cork gaskets.....in my opion they SUCK. i will get some good ones in the mornu=ing and go with them.


Again guys thanks alot for the help i guess I should have looked a little harder before posting.

[bake74]

     Glad to hear you stuck it out and found the problem.