oil in antifreeze is a sign of a head gasket leak, shut car down before major damage is done.
Yes, engine oil and automatic transmission oil can both get into the cooling system.
Nothing will happen if you drain the cooling system and replace the coolant.
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.
When your coolant looks brown in color this means that you have got oil in your cooling system. This is not good, you could have a cracked head gasket or a crack in the block somewhere that is letting oil escape into the cooling system. The foam at the top of the radiator happens when the oil mixes with the coolant and then runs through the water pump. Hope this helps.
Nothing if you drain it out and flush the cooling system. Oil is not a good coolant, and the water pump will have a hard time pumping it, so the vehicle will overheat if you do not remove the oil.
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.
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?
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.
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.
it has a bad head gaskit