[SRGN]

Originally Posted by grivera

Maybe a long shot but did installer forget to put anaerobic sealer between rear main and block?

Great advice here. I've used anaerobic for years on rear mains in my Buick builds. I also use it between the 2 halves of the neoprene rear main seal that I use instead of the rope seal. I haven't had a rear main leak since I started doing it that way. Far superior to silicone.

[steve25]

If you did not install the seal yourself I wonder if it was installed not facing the right way.

Many seals are made such that they need some crankcase pressure to load the sealing lip onto the crank .