What happens when oil cooler fails?

[afnan]

Hi,
I have seen some oil coolers fail. Just out of curiosity in your opinion what is the result of the engine oil cooler failure on 3.0 Ecodiesels?

What I understand is

1. Oil and coolant mix to form a creamy slurry
2. It may clog the radiator.
3. The oil will eat away all rubber parts (Orings or Hoses) as rubber parts are not resistant to petroleum.

Does this meal the engine is ruined? especially 3 as there are many rubber parts cant change all

[drover]

The engine will die well before the rubber gives way , a look at the header tank will give early signs.........its the same with any diesel nowadays as they all have similar coolers on the engine.

[afnan]

Originally Posted by drover

The engine will die well before the rubber gives way , a look at the header tank will give early signs.........its the same with any diesel nowadays as they all have similar coolers on the engine.

Header tank? you mean the expansion tank and what signs to look for? my oil is pure black

[drover]

Black oil is good, its when the red in the expansion/header tank turns from red to grey mucky slop that you worry that means oil has found its way into the system, early sign is a grey/blak high tide mark in tank and a scum under the lid also find a scum under the oil filler cap when coolant/water makes its way into the sump....... If you get serviced by a dealer don't panic if your nice red/pink coolant seems to have a pinky scummy mark in the header tank it an additive which they put in, I think its a leak seal actually.... any sign that the colour of your coolant is changing is cause for an investigation ............ Its not a Jeep thing though other brands have oil cooler failures as well.

[Red1]

When the engine is running the cooling system will fill with oil & overflow the expansion / header tank.

When the engine is stopped the reverse will happen and the oil sump will fill with coolant. The oil level on the dipstick will rise.

Oil pressure is higher then the cooling system pressure when the engine is running.

Also the overflow leaves a lovely mess all under the vehicle.