[my07_335i]

For the last few months, my coolant warning will come on when I hit a bump in the road hard. Pothole, uneven road, you name it. I thought at first it was a leak, but I could drive for a hundred miles without seeing a warning, then hit a small hole in the road, and bam...instant warning. If I turn the car off and back on, it's great again until the next hole. FWIW, it seems to be larger holes/bumps, small ones won't do it.

I've checked the expansion tank every time, it's fairly full/not low, so I don't think I have a leak, the only thing I could think of, is that maybe the sensor is going out, but then I can't explain why it only happens when i hit potholes/bumps.


Any ideas? Google isn't helping me here

[TrAcK TRaP]

Nothing to do with this post but you have pic of your wheel set up with 15/12 spacers. I have the same wheels just wanna see how it looks like your offset is 35F 35R?

[PhaseP]

Could be dirty electrical connection, or just the sensor is toast.

[07lilredwagon]

How many miles on the car?....yes, could be a bad connection...contaminated terminals, ect...but if the water pump is old...could it be on its last legs?

JP

[bman5150]

My coolant expansion tank had a hairline crack. Barely leaked and then started leaking to the point I got the light just two days after topping the fluid off and also saw coolant on my garage floor at work. Dealer replaced under CPO warranty. This was just a few months ago.

[kkasson]

I agree, sounds like a loose connection. The sensor is in a dry part of the tank, you can just unplug it and twist it out. Take it out and check the connectors. I don't remember where the wires on the connector go but you might also try to follow them back a bit and see if you find anything loosen.