How to test the stock OEM Oil Cooler/Warmer?

[kevboost7]

I'm getting some brown sludge in my radiator and coolant reservoir. The engine was rebuilt by the previous owner with forged pistons and rods, and new turbos, etc. I'm suspecting the oil is mixing with the coolant because of the stock oil cooler thing. I read that some of the gaskets can fail and cause the oil and coolant to mix. How do I test if this is the problem? 

[GTSBoy]

17 minutes ago, kevboost7 said:

I read that some of the gaskets can fail and cause the oil and coolant to mix. How do I test if this is the problem? 

It's not a gasket failure. AFIAK, there are no gaskets separating the two fluids. If it lets one into the other, it is broken metal.

[Duncan]

Also, it's highly unlikely to be the cause, especially if there is no milkshake under your oil cap.

Goop in the cooling system is almost always rust from the block due to someone along the way not running enough coolant/rust inhibitor. If it worries you, you can try and flush everything out for a few times.

[The Bogan]

Auto or manual car, there are multiple places for oil and water to mix

I have never heard of one of those warmer/cooler thingos failing before , is that a thing?

[GTSBoy]

7 minutes ago, The Bogan said:

I have never heard of one of those warmer/cooler thingos failing before , is that a thing?

Yeah. Particularly on cars where the maintenance, particularly the coolant maintenance, has not been up to scratch. Coolant turns acidic, eats the HX out, and at some point it becomes too thin to resist the pressure and you get horrible things happen. RBs are moderately famous for it. It's not like it's a problem that happens to all of them. But there've been enough events that people fear it.

[The Bogan]

16 minutes ago, GTSBoy said:

Yeah. Particularly on cars where the maintenance, particularly the coolant maintenance, has not been up to scratch. Coolant turns acidic, eats the HX out, and at some point it becomes too thin to resist the pressure and you get horrible things happen. RBs are moderately famous for it. It's not like it's a problem that happens to all of them. But there've been enough events that people fear it.

Fair enough

OP: If the car is a auto what's the trans fluid look like because the trans cooler in the radiator may have a issue

If there's any milk shake on the trans dip stick you need to get that sorted pronto before the auto eats itself 

 

[kevboost7]

The car is a manual. The fuild in there has been replaced too.

There was actually milkshake under the radiator cap. In fact, the whole coolant was brown milkshake last year. I drained all the brown liquid out via radiator. Replaced the OEM radiator with a Koyo and Replaced all the coolant hoses under the plenum. I re-filled with fresh green coolant, and now i see brown spots contaminating the coolant again. Its not completely taking over like before though. 

I really hope its just left over rust not flushed out properly. 

[TurboTapin]

1 hour ago, kevboost7 said:

The car is a manual. The fuild in there has been replaced too.

There was actually milkshake under the radiator cap. In fact, the whole coolant was brown milkshake last year. I drained all the brown liquid out via radiator. Replaced the OEM radiator with a Koyo and Replaced all the coolant hoses under the plenum. I re-filled with fresh green coolant, and now i see brown spots contaminating the coolant again. Its not completely taking over like before though. 

I really hope its just left over rust not flushed out properly. 

Send your oil out for analysis for peace of mind. 

[Duncan]

If you have an active leak it would be badly contaminated again by now....I'm pretty sure it is just residual.

BTW I suggested checking under the oil cap, not radiator cap.

Finally, cooling system pressure testers are cheap to buy, that will tell you with a reasonable degree of confidence if there is a leak anywhere in that system.