Expansion tank "pop"
 

The other day out of the blue, wife heard a "pop" and the X5 3.0 dumped coolant.

Expansion tank split - classic, right? The one in the car was Meyle and I've ordered a new Behr tank and the ATF thermostat as it was broken when the tank came off. Strange thing though, there was a chunk of plastic sticking out of the split line. I cut the tank apart to look inside (I'm curious), and that chunk of plastic came out of the well where the ATF thermostat sits. The internal ribs of the tank are also broken. So, which came first?

Also, when I removed the tank, I found there was no electrical connection to the level sensor and I can't see the wire. Anybody know where on the harness the sensor wire comes out?

That's some great follow up. I think we (xoutpost) figured out of you have the high level dash you get the level sensor reading but if you have the basic dash you don't.

All the e53 get the same tank so the basic ones end up with a "sensor to nowhere".


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Interesting there's a sensor but no connection. I guess I can call off the hounds.

Yup I replaced my expansion tank a few months ago and likewise nothing to connect to the sensor. I'm thinking of adding an idiot light. Simple circuit with led and resistors that closes when low and gives me a red glow in my grill if the college is low. I would only see when I walk in front of my car but that is daily

Interestingly enough, I have a friend with a similar 3.0 and he says he's seen "low coolant" messages on his. He's in Toronto this week - we'll GTG later and see what he has. Same dash at any rate.

The sensor itself is just a little reed relay that (probably) opens when the level is high enough. There's a ring magnet on the float.

He's seen the message because he has the "wordy" display.