which rear main seal to choose

[ekajkrats]

Fel-pro seems to be popular for seals/gaskets such as the valve cover gaskets.

Is that would I should be looking for on a rear main seal?

Fel-pro blue silicone:
http://www.summitracing.com/parts/fel-2900/overview/make/chevrolet

Or is fluoroelastomer better than silicone in this instance?
http://www.summitracing.com/parts/fel-2912/overview/make/chevrolet

What about timken?
http://www.summitracing.com/parts/tmk-5092/overview/make/chevrolet

Thanks for any advice.

Here is the back story as to why I am going to pull the engine:
The engine is of unknown origin and age and was in there when I purchased the blazer from the PO. Its a 400sb. It as had a small leak that recently started getting worse. I thought it was just the mechanical oil gauge line leaking, but I fixed that and the leak still was happening. Also replaced my brake vacuum booster, and then the oil leak changed from a drip to pouring out the back and down the oil filter and the flexplate cover. Enough oil was pouring out that I would have emptied the engine of oil in minutes if I left it running.

So after I confirm where the oil is leaking from, which I think is likely the rear main seal, I will pull the engine, and replace all accessible gaskets: oil pan, rear main, timing cover gasket, and valve cover. Any other gaskets? Anything else I should do to it while the engine is out?

Thanks for any insight and advice!
-Jacob

 

[diesel4me]

I'd make sure the rear intake manifold rubber seal,if there is one still there,isn't leaking,they often bulge out and let oil ooze onto the bellhousing and mimic a rear main leak...GM reccomends tossing those seals in the rubbish and using a thick bead of RTV instead there at both ends of the intake..

If it is the rear seal,I have no preference,I have only replaced one old style rear main seal and used a Fel-Pro stock looking replacement..this was on a 250 straight six--I had some excess play in the rear main bearing as well,which likely wiped the old seal out,so I bought just the rear main bearing from NAPA and installed that at the same time..didn't leak after,and its a good thing--a socket fell off my ratchet extention lying under the truck it fell and knocked a piece off one of my front teeth...truck would have been torched if it leaked after that job was done ,without the luxury of a lift lying in slush one cold winter day!..

 

[ekajkrats]

Thanks diesel! I will definitely, check thoroughly the intake before I go pulling the whole engine. The PO had a bunch of rtv on the back, almost too much that it was difficult to get the mechanical oil line back in. So I felt back there after the oil was pouring out and didn't feel oil, but I need t get a mirror back there to see what's really going on.

I will probably go with the silicone fel-pro for everything.

Thanks again!