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 (quantity 2) |
A pressurized coolant expansion tank system is used
- To continuously separate the air from the cooling system
- To replenish the system through a hose connected between the coolant expansion tank and the electric thermostat.
A continuous vent into the coolant expansion tank, through a hose connected to the radiator, prevents air locks from forming in the cooling system.
The coolant expansion tank is attached to the front end carrier in the front left corner of the engine compartment. A filler cap, a bleed screw and an engine coolant level sensor are incorporated into the coolant expansion tank. MAX and MIN level markings are molded into the exterior of the tank.
The engine coolant level sensor is located in the underside of the tank body. When the coolant level in the coolant expansion tank is sufficient, the magnetic float is in the top position. In this position the magnetic field closes the switch contacts in the coolant level sensor. When the coolant level drops significantly below the MIN cold fill coolant level, the magnetic float descends, thus the switch contacts disconnected. The engine coolant level sensor sends signals to the Body Control Module/Gateway Module (BCM/GWM) on hardwired connections. Maximum and minimum marks are molded on the tank body.
The coolant expansion tank provides the following functions:
- Service fill
- Coolant expansion during warm-up
- Air separation during operation
- System pressurization by the filler cap.
The coolant expansion tank has an air space of approximately 0.5 to 1 liter (1.06 to 2.11 US pints), above the MAX level, to allow for coolant expansion.