Coolant Expansion Tank

The coolant expansion tank is located in the right side of the engine compartment. The tank is located by a grommet on its underside and positively secured with a bolt and washer to a bracket on the vehicle body and a second bracket that locates in a molded slot in the tank body.

The coolant expansion tank has 2 connections; one for coolant expansion through the radiator overflow and one for coolant inlet into the thermostat housing. The overflow pipe is secured in the tank with a plastic clip. The hose to the thermostat housing is a quick release connector, retained with a spring clip. A third connection adjacent to the overflow connection is not used and sealed with a blanking plug and O-ring seal.

The coolant expansion tank provides the following functions:

• The service fill.
• Engine coolant expansion during warm up.
• Air separation during operation.
• System pressurization by the filler cap
• Coolant level sensing.

Maximum and minimum marks are molded on the tank body.

The engine coolant level sensor locates in a sealed cavity at the bottom of the coolant expansion tank body. A float with an integral magnet is located inside the coolant expansion tank. The coolant level sensor contains a switch that reacts to the position of the magnetic float. The coolant level sensor is hardwired to the central junction box (CJB).

The magnetic float is designed to float very close to the bottom of the tank, significantly below the MIN cold fill coolant level. The magnetic float in this position does not indicate float failure, for example sinking or sticking. The float has a travel distance of approximately 15 mm (0.59 in) from the bottom of the tank.