KaLiKoStreet

Car started steaming and coolant boiling in reservoir this morning on my way to work. I have a 30 min drive to work and it didn't start steaming until i was like 5 mins away from work. Car is an 04 with a Mazda reman engine i put in about 23,000 miles ago. Car doesn't seem to be leaking water and its also not running hot either. Don't have any hot start issues and don't have any noticeable power loss. The steam is coming from the passengers side of the engine near the air pump. There is a small amount of water below the water pump but doesn't seem to be enough to say the water pumps bad. There is a small amount of milkiness on the oil dipstick but no more then normal however, I have a oil overflow/catch can that comes off the top of the oil filler neck. Right below the oil cap I have a hose coming out of the plastic oil filler neck going into a plastic container Ive had since I put the engine in. Now there is oil and water mixed in that container and there is an odd amount of milky oil stuck to the top inside of the oil filler lid. Haven't pulled my plugs yet since its been raining the last week and is still raining. Its odd that the car isn't running hot and isn't having any power loss but the coolant is boiling and blowing out through my oil catch tank. I'm going to pull my plugs as soon as i can and see if they're wet and i know what that means. Does this seem to be a coolant seal failure caught right as it happened or something else maybe like the water pump or something. I was expecting to see completely milky oil on the dip stick if a lot of water was mixing into the oil but its like no more then just condensation on the dipstick. I plugged my obd2 scanner up to it and only code i have is p0456 and I've had it before due to a vacuum hose leak. Don't believe there is any connection between the two there...Maybe a freeze plug failure or most likely coolant seal failure? Its not taking much water either, what it does take it all seems to be blown back into the oil catch can.

Loki

iTrader: (1)

The thing is, coolant and oil don't share a seal in these engines. It's not like a piston engine's head gasket. So I don't know how you're getting steam in the oil, it might just be humidity and oil vapours boiling out of the oil?

However, there's a common issue with the coolant reservoir cracking, which leads to loss of coolant pressure and overheating. The examination is simple, just look for cracks at the coolant neck. The fix is also simple: get a new bottle, but be careful not to break the radiator nipple when installing it. Especially on an 04, that plastic is now 13 years old.

9krpmrx8

iTrader: (46)

Wall of text much?

If it's boiling then the car is overheating. The milky oil has nothing to do with it, it's common in the colder months.

You need to pressure test your coolant system for leaks. But if the pump is weeping then it is bad, no matter how little the amount of coolant is, it should be in your engine and not leaking out of it.