In Reply to: "Check Coolant" error? posted by Dan Masucci on November 20, 2000 at 03:19:01:
My 89 525 did the same thing. Turned out to be the sensor within the coolant expansion tank. It is a "float" that rises and falls within the tank. A "special tool" crafted from a coat hanger allowed me to "exercise" the float and free-up its travel. Check the sensor out before you spend $$$ chasing this down.