Milky oil...trying to find the cause

[czimpel]

End of last season I notice the coolant was low and then check the oil to find it was very milky. Car was running fine, not missing or smelling like antifreeze. So, I decided to pull it and go through and make sure that everything was OK.
Specs
• 291 4.1 block
• Champion Irons
• Fel Pro 1000 Head gaskets
• ARP head studs torqued properly

Findings so far.
• Pulled the plugs before pulling the motor. All looked good except #5 had a tint of rust.
• Suspected possible intake gasket-All looks good.
• Suspected head gasket on DS. Looked good to the eye as far as I can tell.
• Pulled the PS and still no issues found.
• Checked the deck to see if I could notice any visible cracks. None.
• Looked over heads for the same. None.

Could it possibly be lifting a head under boost?

Where would be my next step?

Thanks, Cory

 

[Chuck Leeper]

I'd disassemble the heads and have them pressure tested.
I have seen the irons crack.... And, the alums, too.

 

[czimpel]

I'd disassemble the heads and have them pressure tested.
I have seen the irons crack.... And, the alums, too.

Sounds good, I will get that done. Any other possibilities?

 

[czimpel]

Double.

 

[Nigel]

Head studs might be leaking.

 

[Chuck Leeper]

If the block has been bored, I'd look close at the cyl walls.

 

[87national55]

If the block has been bored, I'd look close at the cyl walls.

Just found a crack on my cylinder wall... small but it’s there.


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[Thumper]

What radiator/oil cooler set up are you using. I have seen stock radiator oil cooler rupture/ crack and put antifreeze in oil.

 

[TurboBuRick]

Coolant can leak into the oil via the front cover as well.

 

[czimpel]

What radiator/oil cooler set up are you using. I have seen stock radiator oil cooler rupture/ crack and put antifreeze in oil.

No oil cooler.

 

[czimpel]

Coolant can leak into the oil via the front cover as well.

I'll check there as well.

 

[rmar]

Biscuit so far everything in this thread could apply.

 

[Chuck Leeper]

One test, that may have provided an answer, was a coolant press test, B4 disassembly.

 

[czimpel]

One test, that may have provided an answer, was a coolant press test, B4 disassembly.

Damn. I was just expecting the intake or head gasket.
What would that prove other than I have an internal coolant leak? It wouldn't help locate it would it?

 

[rmar]

Sure could.

 

[czimpel]

Sure could.

Too late now, but how could you pinpoint where it was leaking on an internal leak?

 

[michael evans]

It might be to late to check the engine at home, but the radiator is easily done.

 

[czimpel]

Sure could.

Too late now, but how could you pinpoint where it was leaking on an internal leak?

It might be to late to check the engine at home, but the radiator is easily done.

No oil cooler and the issue is milky oil.

 

[michael evans]

Seen that you have no oil cooler (like me) and I forgot to edit.

I had a head gasket let go and had to pull the engine to deck the block. I had the same issue (water in the oil).

 

[earlbrown]

You don't have to disassemble your heads to have them pressure tested. Any automotive machine shop should be able to fix you up. Personally I've never seen an 8445 head fail a pressure test.


A cooling system pressure test (or just a GM seal tab) would have been the thing to do before tearing it down.