Oil pan replacement

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Copper Jr

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Good afternoon everyone,

I am trying to replace my oil pan and the rear main seal is off about an inch. Only info I have on the truck is 1986 k10 305/465/208. Is there something simple I’m missing here. I ordered the pan from summit racing and I’m just looking for guidance on where and what to order. Thanks
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Copper Jr

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I’m thinking I have a two piece main seal and the new oil pan is for a one piece
 

HOTFOOT

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that would be my guess, picture of the back of your eng.
 

Copper Jr

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that would be my guess, picture of the back of your eng.
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QBuff02

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That's a two piece rear main seal engine with a one piece rear main oil pan. I believe '86 is when they started going to one piece rear main seals. Your truck falls in that split, or the engine has been replaced at some point in the truck's life with an engine of earlier vintage. You need a different oil pan from an early (two piece rear main) design. The mouth of the pan is wider when you have a one piece rear main seal.
 

Copper Jr

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Thanks for confirming ordered correct pan, should be here soon.
 

Copper Jr

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Got the replacement for two main seal fit great. Still leaking oil pretty bad. Any way to tell if it’s the rear main seal?
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bucket

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I bet if you run the numbers on the block, it's not original to the truck. 86's got a 1-piece main, it wasn't a split year kind of thing.
 

bucket

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Also, your flywheel appears to be dry, which leads me to believe that something up top is leaking. Maybe valve cover gaskets, the rear of the intake manifold, or maybe a leaking oil pressure sender.
 

Copper Jr

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Also, your flywheel appears to be dry, which leads me to believe that something up top is leaking. Maybe valve cover gaskets, the rear of the intake manifold, or maybe a leaking oil pressure sender.
Definitely one of the valve covers, it has a stripped bolt I am planning on fixing this weekend. We will see if that helps and I’ll look into the block numbers also
 

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