rear main seal if no one never seen it.

 

 

I don't believe that's an OEM seal. All the ones I have seen (or purchased at the dealer) are the Brownish like the crank and cam and not Black.

 

Did OEM change or isn't that OEM?

Brown vs. black doesn't really matter. Either can be of several types of seal compounds.

 

I expect that the OEM seal is Viton. My reasons for suspecting this are that they generally last forever and are in an innacesible location. Unlike the cam seals (which are clearly Nitrile from how hard and cooked they get), the rear mains stay soft and supple upwards of 300k miles. That indicates a very high tollerance for temperature - which would be in accordance with Viton or silicone but I highly doubt they are silicone. I've never seen a silicone lip seal in brown or black anyway.

 

Nitrile is a very poor choice for the rear main - it's actually a poor choice for the front main and the cam seals but that's what they use. Nitrile is good to 225* F and that's on the edge of where these engines run. Their life would be improved if something like Viton or Polyacrylate were use to replace them. Cost is the primary factor here with Viton seals being many times more expensive than Nitrile.

 

GD

Edited August 25, 201015 yr by GeneralDisorder

I don't believe that's an OEM seal. All the ones I have seen (or purchased at the dealer) are the Brownish like the crank and cam and not Black.

 

Did OEM change or isn't that OEM?

 

it's not OEM it's Fel-pro