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Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 999
Experience:  Senior Technician
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I can't stop the rear oil seal on my 400 ci small block

Customer Question

I can't stop the rear oil seal on my 400 ci small block Chevy from Leaking. I've replaced it twice, and both times it starts to leak after about a week. Is there more that one size crankshaft used in the 400 SBC? How can I be sure I'm using the right seal?
Submitted: 1 year ago.
Category: Chevy
Expert:  Gary replied 1 year ago.

Hi there,

If the block has had the main saddle aligned honed, the seal bore will now not be the correct fit in the block.

There are two seal diameters available.

You made need this one:

Tiny bit of sealant on the outside, and the parting join, and stagger the joints.

Also ensure your oil leak is not coming from the rear camshaft plug.

Hope this helps.


Expert:  Gary replied 1 year ago.

Hi again,

I hope my advice has been of assistance to you.

Kind regards