Coolant Leak and Overheated!!!!!

[chiefcorey]

I've only had my 540i for 2 weeks and a day.

I'm driving over the bridge up hill, and the alarm starts going off and I notice that the temperature is going out of control. It was in the red before I could pull over.

Got the car stopped, cooled down, then drove slowly at a high temp to a gas station.

It was clearly out of or low on coolant, so I started filling the resevoir with water. Then the steam back like crazy before I had filled the resevoir.

Before I go on, I'll tell you that I know zero to nothing about engines. But what I did find was a hose that was coming out of the bottom and came up and was not attached. I wish I had taken a picture of it, but maybe I can get one tomorrow.

Anways, it had a broken neck at the plastic box it was attached to.

Do you guys know what it was attached to? I assume it now needs to be replaced, but dont' even know what it is. I left the car at my mechanics, but would like to know what you all think.

And finally, do you think any damage happened to my car while it was running in the red heat range? It would have only been a short bit, but could anything serious have occurred? I suppose it could, but what I'm looking for is better understanding on how strong this v8 really is and if it could have stood up to a minute or so in the red with the engine in neutral as i rolled down a hill to a spot i could pull over.

Thanks!!!!!!

[colo525i]

It sounds to me like the thermostat housing ruptured (plastic "box" on the engine). The thing to do in the situation is to replace the broken housing, toss in a new thermostat for good measure and refill with coolant/water and see if the temp is still ok. You did the right thing tossing the transmission into neutral and coasting. These engines are not very tolerant of being overheated, but the parts should only be about $50, so the diagnosis is cheap.

[chiefcorey]

The mechanic looked and said it's actually the heater control valve casing. Apparently it's all one unit, part # 64118391417 and is about $250 CND. Not good. The casing can't be purchased separately from the pump that's inside it.

[632 Regal]

Call BMAparts.com, last I checked a brand new one (complete with pump) was about 75.00 US

[chiefcorey]

Call BMAparts.com, last I checked a brand new one (complete with pump) was about 75.00 US

Thanks, it's $120 US plus shipping etc. now. i'd save a bit of money, but then wouldn't have my car all weekend. That's the problem with repair work that needs to be done to get the car on the road again, as opposed to brakes, engine mounts, etc, that you can just fix whenever you get your parts.

Will you get a discount at BMAparts.com if you create a login? just wondering for future reference.

[632 Regal]

you get a discount by calling your order in, their website prices are not usually the same as when you call.

You can bypass the heater valve for the weekend and fix it after the new parts come in. Thats what I had to do once, used a plug and a short piece of 1/2" copper pipe and good to go. The plastic pump casing cracked on mine.

Theres almost always a way around being completely down...This is my only transportation as of now (besides the E31 which is allergic to mud).


Thanks, it's $120 US plus shipping etc. now. i'd save a bit of money, but then wouldn't have my car all weekend. That's the problem with repair work that needs to be done to get the car on the road again, as opposed to brakes, engine mounts, etc, that you can just fix whenever you get your parts.

Will you get a discount at BMAparts.com if you create a login? just wondering for future reference.