General Description
The cooling system consists of the following components:
| • | A radiator |
| • | A coolant recovery reservoir |
| • | Electric engine coolant fans |
| • | A thermostat |
| • | A water pump |
| • | An accessory drive belt |
These maintain an efficient engine temperature level during all engine operating conditions.
The system directs some engine coolant through hoses to the heater core in order to provide defrost and passenger compartment heat.
A coolant recovery reservoir connects to the radiator in order to recover engine coolant displaced by expansion.
As the engine cools, vacuum draws coolant back into the radiator.
3800 (VIN K) Engine
On the 3800 (VIN K) engine, the water pump draws the coolant from the radiator. The coolant circulates through coolant jackets in the cylinder block, and then through coolant jackets in the cylinder heads. The coolant is then directed back to the radiator.
5.7L (VIN P) Engine
On the 5.7L (VIN P) engine, coolant is drawn from the radiator by the water pump. The coolant is circulated through coolant jackets in the cylinder heads, then through coolant jackets in the engine block. The coolant is then directed back to the radiator.
Engine Coolant Temperature Gauge Sensor
This sensor controls a temperature gauge in the instrument panel. This gauge indicates the operating temperature of the engine. Refer to Section 8A for engine coolant temperature gauge location and diagnosis.
Engine Coolant Temperature (ECT) Sensor
This sensor sends a signal to the powertrain control module (PCM), which completes the ground for the electric engine cooling fan relays. This sensor operates the fan when the engine coolant temperature exceeds 110°C (230°F).
Engine Block Coolant Drain Hole Plug 3800 (VIN K)
The engine block coolant drain hole plugs are on either side of the engine block just above the oil pan. Knock sensors are installed in both drain holes. Remove the plugs and the sensors when you completely drain the cooling system.
Engine Block Coolant Drain Hole Plug 5.7L (VIN P)
The engine block coolant drain hole plug is on the left side of the engine block. Remove the plug when you completely drain the cooling system. Also, remove the knock sensor on the right side of the engine block.
Long Life Coolant
This vehicle has a newly developed engine coolant. GM Goodwrench DEX-COOL™ was developed to last for 166 000 km (100,000 mi) or 5 years, whichever occurs first. Follow the instructions in Draining/Filling Cooling System. Make sure only GM Goodwrench DEX-COOL™ (orange-colored, silicate-free) is used when coolant is added or changed.
A 50/50 mixture of ethylene glycol (GM Goodwrench DEX-COOL™) and water will provide this protection:
