That's not the question you need to ask yourself. There's not supposed to be any oil in your cooling system, so you need to take your truck to a diesel service and get it fixed.
Yes, engine oil and automatic transmission oil can both get into the cooling system.
Low engine oil can effect the cooling system as it creates additional friction which may be difficult for the cooling system to remove. The oil is designed to both lubricate and cool the internal components.
It will take a few flushings to get all of that solution back out of the to be oil in the cooling system so it probably doesn't have a lot of oil removal capacity.
A broken piston ring can allow oil to get into your cooling system. A bad valve seal can also allow oil into the cooling system.
The oil cooler is inside (actually under the intake plenum) !
Once you have determined and repaired how the oil got into the cooling system eg. head gasket , oil cooler, or turbo, you need to thoroughly flush out the cooling system with a chemical cooing system flush and plenty of water.
does cooling system hold pressure?
The cooling system in the 198 Expedition includes the radiator and its reservoir along with the thermostat. This system included an oil cooler as well, depending on the model purchased.
Answer 1The oil doesn't really cool the engine. It reduces friction which means there is less heat but the coolant and radiator is what cools the engine. Answer 2, Another OpinionI have to disagree with answer one regarding engine cooling. I agree it is intended to reduce friction, BUT it does pick up a great deal of heat, which has to be removed to protect the oil from breakdown. Some engines actually have a separate oil cooler [I'm not talking about the transmission oil cooler] for cooling the crankcase oil. and some, like the Jaguar, have heavy cast aluminum oil pans with fins, designed to dissipate heat from the oil.I agree that the radiator system is designed for and does the bulk of the cooling, but the motor oil circulation system does contribute by distributing and disipating some of the heat.j3h.
it has a bad head gaskit
System pressure will run abnormally high, the AC system will vibrate, and you won't get proper cooling.
Oil is used as the x-ray tubes cooling system.