Volvo Repair: S70 Radiator Sensor Light - Volvo 1999, coolant level, heater cores

Question
James, the bottom radiator hose clamp broke and lost all coolant. Replaced hose and coolant but the sensor light continues to come on  when attempting to drive. I parked it on concrete to check for leaks and let it idle. There was no leak evidence after 40 minutes. No sensor light either but when I let it cool and restarted the engine the light came on and remains on.

Thank you, James White

Answer
Well the coolant level will go down several inches in the resevoir when it heats up so make sure the resevoir is almost full to start.  Then when it gets to operating temp the level will be in the correct spot.  You should try to take the car somewhere to get the system pressure tested  because that is the best way to find leaks.  Your most likely problem is the radiator or possibly head gasket since you lost coolant while driving before.  The radiator cracks along the side tanks so look for coolant residue there.  Also the heater cores on these cars sometimes leak so check the drain of the a/c case inside the car.  If no leaks turn up anywhere checkout the coolant level sensor on the bottom of the resevoir.  They sometimes come apart giving a false reading.

James