Fixer pluged radiator or caused thermostat to stick shut.
It could be a head gasket or cracked head. With the engine cold, take the radiator cap off and crank the engine. If the head gasket is bad coolant should shoot out of the radiator. 12 inches to possibly hitting the hood.
water pumps in malibus can fail because the plastic impeller can spin on the steel shaft. If the water pump is ok then it is probably a head gasket.
Problem?
My 1971 chev truck has 319,000 miles on it & the heads have never been off - If U don't overheat the engine & KEEP the oil changed U shouldn't have a head gasket problem.* keep antifreeze & water pump lube in the radiator.
I would suggest you replace the thermostat, and flush the cooling system. Also check the radiator fins and see if they are clean and free of debris.
There may have been some Bar's leak/stop leak added at one time. Flush system. If that's not the case and it's a milk shake consistency, then you could have a bad head gasket allowing oil into the coolant.
To flush a radiator on an Acura RL you will need to make sure the care is level. Remove the radiator cap from the radiator under the hood. Place a bucket under the radiator and remove the radiator plug. This is a white plug located on the bottom of the radiator which may be hidden by the splash guards at the front of the vehicle. After the radiator fluid has been drained replace the white radiator plug. Refill the radiator with coolant and replace the radiator cap.
Most of the time it is because the thermostat has gone bad and is not opening at the proper temperature. Cure: replace thermostat. If the thermostat has been replaced, flush the radiator. Buildup of residue in the bottom of the radiato0r will cause overheating, but it is maintained over heating, not temporary.
It probably overheats due to a leaking head gasket. I'm assuming everything else has been eliminated such as the water pump, radiator, thermostat etc. I raced using 400 Cubic Inch Chevrolet Motors and know them fairly well.
It could be any number of things, but I'd check for bad fan relay or fuse, sticking thermostat, blocked radiator or blown head gasket.
No, the two should never mix. If the engine has ever been overheated it could have caused the head to warp resulting in a blown head gasket. Oil in the coolant is one indication of a blown head gasket so you might want to take care of that before driving anywhere else.
As long as the engine didn't overheat you should be O.K.