Cooling System Component Views (Hatchback)
| Callout | Component Name |
|---|---|
| 1 | Bolt |
| 2 | Radiator Bracket |
| 3 | Radiator Bumper |
| 4 | Radiator |
| 5 | Drain Cock |
| 6 | Spring Clamp |
| 7 | Upper Radiator Hose |
| 8 | Cooling Fan |
| 9 | Bolt |
Scheme 7
| Callout | Component Name |
|---|---|
| 1 | Bolt |
| 2 | Radiator Bumper |
| 3 | Radiator Bracket Bolt |
| 4 | Radiator Bracket |
| 5 | Radiator |
| 6 | Drain Cock |
| 7 | Upper Radiator Hose |
| 8 | Cooling Fan (Main) |
| 9 | Cooling Fan (Auxiliary) |
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions.
Engine Overheating
| Checks | Actions |
|---|---|
| Check for a loss of the coolant. | Add the coolant. |
| Check for a weak coolant solution. | Confirm that the coolant solution is a 50/50 mixture of ethylene glycol and water. |
| Check the front of the radiator for any dirt, any leaves, or any insects. | Clean the front of the radiator. |
| Check for leakage from the hoses, the coolant pump, the heater, the thermostat housing, the radiator, the core plugs, or the head gasket. | Replace any damaged components. |
| Check for a faulty thermostat. | Replace a damaged thermostat. |
| Check for retarded ignition timing. | Perform a code diagnosis using the engine control module (ECM) for a vehicle with a manual transaxle. Confirm the integrity of the timing belt. |
| Check for an improperly operating electric cooling fan. | Replace the electric cooling fan. |
| Check for radiator hoses that are plugged or rotted. | Replace any damaged radiator hoses. |
| Check for a faulty water pump. | Replace a faulty water pump. |
| Check for a faulty surge tank cap. | Replace a faulty surge tank cap. |
| Check for a cylinder head or an engine block that is cracked or plugged. | Replace a faulty water pump. Repair the damaged cylinder head or the damaged engine block. |
Loss of Coolant
| Checks | Actions |
|---|---|
| Check for a leak in the radiator. | Replace a damaged radiator. |
| Check for a leak in the following locations: Surge tank Hose | Replace the following parts: Surge tank Hose |
| Check for the following loose or damaged parts: Radiator hoses Heater hoses Connections | Reseat the hoses. Replace the hoses or the clamps. |
| Check for leaks in the coolant pump seal. | Replace the coolant pump seal. |
| Check for leaks in the coolant pump gasket. | Replace the coolant pump gasket. |
| Check for an improper cylinder head torque. | Tighten the cylinder head bolts to specifications. Replace the cylinder head gasket, if needed. |
| Check for leaks in the following locations: Intake manifold Cylinder head gasket Cylinder block plug Heater core Radiator drain plug | Repair or replace any components, as needed, to correct the leak. |
Coolant Heater Inoperative
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Test the engine coolant heater power supply cord for an open or short to ground. Refer to Circuit Testing . Did you find the condition? | Go to Step 3 | Go to Step 4 |
| 3 | Replace the engine coolant heater power supply cord. Refer to Coolant Heater Cord Replacement . Did you complete the repair? | Go to Step 6 | |
| 4 | Inspect for poor connections at the harness connector of the engine coolant heater. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find the condition? | Go to Step 6 | Go to Step 5 |
| 5 | Replace the engine coolant heater. Refer to Coolant Heater Replacement . Did you complete the repair? | Go to Step 6 | |
| 6 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Engine Fails To Reach Normal Operating Temperature
| Checks | Actions |
|---|---|
| Check to determine if the thermostat is stuck open, or if it is the wrong type of thermostat. | Install a new thermostat of the correct type and heat range. |
| Check the coolant level to determine if it is below the MIN mark on the surge tank. | Add sufficient coolant to raise the fluid to the specified mark on the surge tank. |
Tools Required
J-36649 Cooling System Pressure Test Adapter. See Special Tools .
Radiator
This vehicle has a lightweight tube-and-fin aluminum radiator. Two models of radiators are available: small, standard, and heavy duty. The 2 models vary only by capacity. Plastic tanks are mounted on the right and the left sides of the radiator core.
On vehicles equipped with automatic transaxles, the transaxle fluid cooler lines run through the left radiator tank. A radiator drain cock is on this radiator.
To drain the cooling system, open the drain cock.
Surge Tank
| CAUTION | As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously - possibly with explosive force - spewing the solution over the engine, fenders and the person removing the cap. |
The surge tank is a transparent plastic reservoir, similar to the windshield washer reservoir.
The surge tank is connected to the radiator by a hose and to the engine cooling system by another hose. As the vehicle is driven, the engine coolant heats and expands. The portion of the engine coolant displaced by this expansion flows from the radiator and the engine into the surge tank. The air trapped in the radiator and the engine is degassed into the surge tank.
When the engine stops, the engine coolant cools and contracts. The displaced engine coolant is then drawn back into the radiator and the engine. This keeps the radiator filled with coolant to the desired level at all times and increases the cooling efficiency.
Maintain the coolant level between the MIN and the MAX marks on the surge tank when the system is cold.
Coolant Pump
The belt-driven centrifugal coolant pump consists of an impeller, a drive shaft, and a belt pulley. The coolant pump is mounted on the front of the transverse-mounted engine, and is driven by the timing belt.
The impeller is supported by a completely sealed bearing.
The coolant pump is serviced as an assembly and, therefore, cannot be disassembled.
Thermostat
A wax pellet-type thermostat controls the flow of the engine coolant through the engine cooling system. The thermostat is mounted in the thermostat housing to the front of the cylinder head.
The thermostat stops the flow of the engine coolant from the engine to the radiator to provide faster warm-up, and to regulate the coolant temperature. The thermostat remains closed while the engine coolant is cold, preventing circulation of the engine coolant through the radiator. At this point, the engine coolant is allowed to circulate only throughout the heater core to warm it quickly and evenly.
As the engine warms, the thermostat opens. This allows the engine coolant to flow through the radiator where the heat is dissipated through the radiator. This opening and closing of the thermostat permits enough engine coolant to enter the radiator to keep the engine within proper engine temperature operating limits.
The wax pellet in the thermostat is hermetically sealed in a metal case. The wax element of the thermostat expands when it is heated and contracts when it is cooled.
As the vehicle is driven and the engine warms, the engine coolant temperature increases. When the engine coolant reaches a specified temperature, the wax pellet element in the thermostat expands and exerts pressure against the metal case, forcing the valve open. This allows the engine coolant to flow through the engine cooling system and cool the engine.
As the wax pellet cools, the contraction allows a spring to close the valve.
The thermostat begins to open at 87°C (189°F) and is fully open at 102°C (216°F). The thermostat closes at 86°C (187°F).
Electric Cooling Fan
| CAUTION | Refer to Electric Coolant Fan Caution . |
| CAUTION | Refer to Damaged Fan Blade Caution . |
The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling fans increase the flow of air across the radiator fins and across the condenser on A/C-equipped vehicles. This helps to speed cooling when the vehicle is at idle or moving at low speeds.
The fan size is 366 mm (14.4 in) in diameter with 5 blades to aid the airflow through the radiator and the condenser. A non-A/C model is 300 mm (11.8 in). An electric motor attached to the radiator support drives the fan.
A/C OFF or Non-A/C Model
- The cooling fans are actuated by the engine control module (ECM) using a low-speed cooling fan relay and a high-speed cooling fan relay. On A/C-equipped vehicles, a series/parallel cooling fan relay is also used.
- The ECM will turn the cooling fans ON at low speed when the coolant temperature reaches 93°C (199°F) and high speed at 97°C (207°F).
- The ECM will change the cooling fans from high speed to low speed at 94°C (201°F) and turn the cooling fans OFF at 90°C (194°F).
A/C ON
- The ECM will turn the cooling fans ON at low speed when the A/C system is ON. The ECM will change to high speed when the coolant temperature reaches 97°C (207°F) or high-side A/C pressure reaches 1 882 kPa (273 psi).
- The cooling fans will return to low speed when the coolant temperature reaches 94°C (201°F) or high-side A/C pressure reaches 1 448 kPa (210 psi).
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature (ECT) sensor uses a thermistor to control the signal voltage to the engine control module (ECM) and controls the instrument panel temperature indicator. The ECT sensor is located on the cylinder head. Refer to the appropriate engine controls section for diagnosis and replacement of the sensor.
Engine Block Heater
The vehicle is designed to accept an engine block heater. The engine block heater helps to warm the engine for improved cold weather starting. It can also help reduce fuel consumption when a cold engine is warming up.
The engine block heater utilizes an existing expansion plug for installation and is located in the engine block in an existing freeze plug port.
Contact your General Motors dealer for further information or installation.