oil in coolant (1 Viewer)

[vinny tetravino]

ok Ill just start by saying that I am a heavy duty mechanic and that I worked as a mechanic at toyota

so I recently bought an used 3b from radd cruisers due to the dreaded dropped precup which exploded my piston wore a groove in the head and the block...
it gave me some issues so I got the head done valves ect. ran great for about a year got better all the time
the other day checked my fluids and my coolant was black with oil on top so I thought it was possibly residuals from the popped engine and proceded to flush the coolant system 4 times
refilled drove for a week and the black gooo is back in my rad it is strange that it doesnt really mix with the coolant but just sits on top in the rad and the overflow. There is no coolant in the oil there is no exaust coming out the coolant system the truck runs awsome and doesent overheat wtf

so wtf is going on is it a leaky oil cooler or a head gasket I am leaning towards oil cooler.... but not sure


any extra brains to wrap around this one would be appreciated

 

[IanB]

Are you able to do a leakdown test to rule out a bad HG?

 

[RufusTheDufus]

Do you have an oil pressure gauge on the engine?

There's two oil pressure relief valves in a 3B. One is built into the pump housing on the front of the block. The other is in the oil filter housing. Either of these could stick causing higher than normal pressure in part of the oil circuit.

If the oil cooler was failing I'd expect you to see a least a little coolant in the oil too. (Or at least milky coolant condensation on the bottom of the oil filler cap.) The oil pressure is generally higher than the cooling system pressure when the engine is running if your radiator cap is working. But when you shut down oil pressure goes to zero but the cooling system pressure goes up from heat soak. I'd expect a little coolant to get into the oil at this time. Maybe it's not enough to notice and could be evaporating?

Does the engine have a turbo?

Any chance it could be fuel and not engine oil?

 

[vinny tetravino]

I dont think a leak down test would help as there is no exaust getting out of the head and that is a lot more pressure than a leakdown

the oil pressure is good never get s too high around 40 psi at cruising speed
the bottom of the filler cap gets black sludge on it after a day of running around
there is definitely no coolant in the oil and I agree with the coolant pressure rising after shut down but maybe not enough pressure to leak?
there is a turbo, with both coolant and oil lines, but it seems fine I am sure the they are not mixing there
it is definitely oil in the system not fuel, too black for fuel

in any case I have the oil cooler gaskets on order

 

[BEE-JAY42]

Go to Cummins and buy a product called restore, run it through your radiator then flush it. It will clean out absolutely all oil from the previous failure. If you get more oil after that then you have oil making it's way into your cooling system without a doubt.

 

[vinny tetravino]

been there done that last week and the oil returned no doubt that the oil is there

 

[vinny tetravino]

no one has ever had this problem??

 

[vinny tetravino]

just so ya know I did the head gasket and the oil cooler and its gaskets yesterday It sure looked like the cooler orings were the problem

 

[buschmaster86]

and where the cooler o rings the problem ?

 

[Bisonthecruiser]

Anyone have this same issue with a 1HDT? There is nothing online anywhere about this issue that I can find. But hey, it's me searching.