I just finished installing a used but good condition 403 in my Studebaker pickup. Prior to installation, I removed the pan and intake to clean out sludge and installed a new oil pump and timing chain. After running it about 50 miles I have oil in the coolant but no coolant in the oil. Some sites seem to suggest the intake gasket (felpro turkey pan) could cause this. Is that possible? If not, do you have any suggestions before I pull the motor apart? Many thanks for your help!

 

Welcome to the site. Is it oil or transmission fluid?

 

Thanks for the welcome. I have a separate transmission cooler so it is motor oil. I drained the oil and there is absolutely no coolant in the oil. However,when I drained the coolant I found at least a half pint of oil.

 

Did you use RTV around both sides of the turkey tray on the 4 outside water ports?

 

Yes. However, this build took some time and I am not sure I re torqued the manifold bolts after I ran it the first time.

 

That sounds like a cool truck! The Olds 403 should be a great dependable engine also. My guess would be the intake sealing also. Let us know what you find, and pics of the truck, please...

 

You would think that with a leaking manifold gasket you'd find water in the oil as the water is pressurized and the oil is not.

 

The oil is not pressurized around the intake area, but the oil pump puts out 40-50 psi vs the coolant that has a 15 psi cap (maybe). I can't think of where pressurized oil would get into the coolant passages, though. Every time I had any issues, it was as you said with water in the oil.

 

Thanks to all who replied. It sounds like I need to take it apart and see what the problem is. Greg asked for pictures so I will attach some.

 

Good looking truck, love the color.

 

That's true the oil pressure when the engine is running is higher than the coolant. However when you turn the engine off the coolant pressure is higher and you'd think it would get into the oil.

 

It does not make good sense that the intake is causing the problem but that is the only part of this original engine that was disturbed since it was in a rusty 98 and not leaking oil into the coolant. Also, my neighbor and I ran a radiator pressure test and it seemed ok both ways (pressurized and running). I must be missing something obvious

 

Just to confirm, the transmission lines do not go into the radiator at all? Typical setup for aux cooler is Transmission -> Aux Cooler -> Radiator -> return.


I wonder if oil can get around the timing cover.

 

I am using a racing radiator and the separate transmission cooler is connected directly to the transmission. I will give your other idea some thought. thanks

 

I assume you have no engine oil cooler.

 

No separate oil cooler but I did find this tech tip in the Dick Miller Racing parts catalog:

A customer once complained that his intake was leaking oil between the intake and head on both sides near the carburetor (I did find a pool of oil there). For oil to get by the gasket at that spot, one or both surfaces are not flat. Remember a surface that may be warped by heat and the gasket will still seal until disassembled. Then when the parts are reassembled, they may leak unless they are resurfaced.

I do not own a machinists straight edge but with the best steel rule I own, the intake manifold sure seems warped. So until I learn different from a machine shop, that sure seems like my problem.

Thanks to all who responded!

 

I like that truck! Did you get it fixed yet?

 

What intake? If it is an Edelbrock, many come out of the box far from straight.