My 1995 M3 has recently started to flash "Check Coolant Level, See Owner's Manual" on the OBC display when turning the eninge off. Initially, I added some more coolant to the reservoir. Now with the flashing message again, it appears that there is enough coolant but still I am getting the warning message. Is it possible the sensor is faulty or could there be another real problem somewhere else?
The sensor for the coolant level is on the bottom of the expansion tank, which is on the passenger side of the radiator. On the left when standing in front of the car with hood open. Actually now that I think about it, the expansion tank is where you add coolant. If you look at the bottom of the tank there is a sensor attached onto the bottom of the tank. So if the coolant is completely covering the sensor and you are still getting the message than it is probably a faulty sensor or wiring. Make sure the wire connection to the sensor is clean and not corroded. That would be my first place to look. Other wise it might be the sensor or something else. Needless to say, if you have the correct level of coolant in your car and the car is not consuming coolant, this warning is not indicating a worse problem. It only informs you of the level of coolant in the expansion tank (when it is working properly).
Thanks for the reply. After posting my message I saw the links to related questions and understood better what the problem was. The error message is intermittent so I am fairly certain the sensor is either failing or sending an occasional false signal.
