'04 BMW 330i. automatic, 99k miles (Wifemobile) Sounds like I have ghosts under the hood.
3 weeks ago I replaced the gasket beneath the oil filter housing. Noticed that coolant had been slinging off the water pump pulley. No significant water loss. No worries, I will take care of it next time she is out of town.
1 week ago: “Honey, did all this water running across the parking lot come out of my car?”
This morning I replaced water pump, both thermostats, radiator, expansion tank, three hoses, fan clutch, tensioner on accessory belt, and several O-rings. After fifteen years of driving BMWs, I have learned that when you have to go in to the cooling system, you go all the way.
On restarting car, I have a whistling/moaning sound. Comes and goes randomly. Not related to engine speed other than perhaps it is a bit more pronounced on deceleration. Took a trip to the store, and after about 10 miles it quieted down to where I did not notice it. The noise was back when I pulled the car into the garage after washing it. It is loud enough that people turn and look curiously at the car at stop lights.
My theory: Head got pretty hot as we drove to gas station for water to get us home last Sunday. Perhaps that hardened the intake manifold gasket enough to make it leak? Idle is perfectly smooth, so if it is a vacuum leak, it is not yet a big one.
Any other theories?