Coolant Expansion Tank
| ITEM | DESCRIPTION |
|---|---|
| 1 | Bleed screw |
| 2 | Hose connection - Engine coolant outlet |
| 3 | Hose connection - Radiator |
| 4 | Filler cap |
| 5 | Maximum and minimum level markings |
| 6 | Mounting lug |
| 7 | Hose connection - Engine coolant inlet |
| 8 | Engine coolant level sensor |
| 9 | Mounting lugs |
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.
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 Body Control Module (BCM)/Gateway Control Module (GWM).
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.
Minimum and maximum level markings are molded on the coolant expansion tank body. The coolant expansion tank has an air space above the maximum level, approximately 0.5 liter (0.13 gallon) to 1 liter (0.26 gallon). The air space allows the engine coolant to expand.