Winter is just around the corner. Days are getting shorter and the weather is turning colder. As you get in your car and drive to your destination you notice that the cabin in your BMW isn’t getting any warmer. You put your hand against the vent and you feel cool air coming through. You double-check that your heat is on, but your cabin isn’t getting any warmer. Your car is now uncomfortably cold for winter driving. This is a common sign that you have a failing thermostat.

Your BMW’s engine cooling system is very efficient. It is so efficient that your engine will never have the opportunity to get to operating temperature to burn fuel optimally or heat up your cabin. That is where your BMW’s thermostat comes into play. The thermostat is a device that is calibrated to lock coolant inside your engine until it reaches a specific temperature. Then the thermostat opens and allows coolant to reach your radiator to cool it and maintain operating temperature.

As the thermostat ages, it can fail in a couple of ways on your European automobile. It can leak causing your car to lose coolant and overheat. The thermostat can fail in a closed position causing your engine to overheat. Finally, the thermostat can fail in an open position causing your coolant to never reach operating temperature. As your coolant stays cold there is no heat source to warm your cabin and your vents will blow cold.

If you notice that there is no heat coming from your BMW vents, you should bring it in to get diagnosed. A thermostat replacement can turn into a big repair if the failed component is left unattended.