Sensor is closed when full... (archive)

The coolant sensor is closed when the tank is full, open when low. This is the opposite of what you'd think, the opposite of what Bentley's schematic indicates, and the opposite of what BMW's own ETM for '86 says. But it's what I say.

I assume you are saying the check light is blinking because your coolant level sensor is indicating low coolant. Well, assuming your level is fine, play with it in your fingers. If you push that sleeve that floats on the coolant up (indicating full coolant), and then turn on the ignition, your check should go off. I have noticed that my check panel does not monitor coolant on an ongoing basis--once the engine is running, regardless of whether or not you fix the problem, the light is staying on until you restart the car. Hence, it is important you turn the ignition off and on when checking this thing.
Now, if that doesn't work, you could double check by making sure resistance is zero across the contacts when it's closed (I believe signal stops flowing when the tank is full--somebody correct me if it's backwards), just to make sure it's not a problem with the sensor going to the check unit, although I've never heard of that happening. It's probably just your coolant sensor coincidentally going bad. . .

David
'88 535iS-"Hannah"
111k

Follow Ups:

[ Follow Ups ] [ 5-series (E28) Message Board ] [ Msg. Board FAQ ]

Questions, comments, or problems, please visit the Roadfly help desk.