Have a 2001 DeVille. When I turn on the ignition I get a warning message “check coolant level” After driving for several minutes the message disapears. Have checked the coolant level and it is OK. What is causing the message to appear?
How was the coolant level checked? Was it the reservoir or the radiator? Was it with the engine hot or cold?
When you first start the car the volume of coolant will be at its lowest. When the car heats up the coolant expands and flows into the reservoir. If you are a little bit low on coolant, it may only trigger the level sensor when the car is cold.
Try changing the radiator cap. The sensor that brings up the light is in the radiator but you check the coolant in the overflow reservior. If your cap is faulty, it can stop coolant from getting from the reservior to the radiator.