Step | Action | Value | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
DEFINITION: Engine temperature lamp comes ON and stays ON, or the temperature gauge shows hot, or coolant overflows from the reservoir onto the ground while the engine is running. | ||||||||
1 | Check for a loss of coolant. Is there a loss of coolant? | -- | ||||||
2 | Fill the system to the specified level. Refer to Loss of Coolant . Does the engine overheat? | -- | System OK | |||||
3 | Check for low coolant protection, Refer to Coolant Concentration Testing . Is the coolant to the correct concentration? | -- | ||||||
4 | Check for a loss of system pressure, Refer to Cooling System Leak Testing . Is there a loss of system pressure? | -- | ||||||
5 | Check for a faulty engine coolant temperature (ECT) sensor. Refer to Cooling System . Is the sensor operating properly? | -- | ||||||
6 | Check for a cracked coolant recovery reservoir or a leaking hose. Refer to Loss of Coolant . Is the reservoir cracked or is the hose leaking? | -- | ||||||
7 | Repair or install new parts as necessary, then retest. Does the engine overheat? | -- | System OK | |||||
8 | Check for incorrect drive belt tension. Refer to Drive Belt Tensioner Replacement in Engine Mechanical. Is the belt to the correct tension? | -- | ||||||
9 | Check for incorrect ignition timing. Is the timing incorrect? | -- | ||||||
10 | Check for a damaged water pump driveshaft. Is the water pump driveshaft damaged or is the seal leaking? | -- | ||||||
11 | Check for obstructed radiator air flow or bent radiator fins. Refer to Radiator Assembly . Is the radiator air flow obstructed? | -- | ||||||
12 | Are the cooling system passages blocked? Refer to Flushing . Add fresh coolant to GM specification 6277M. | -- | ||||||
13 | Check for inoperative cooling fans.
Are the cooling fans and the motors operating correctly? | -- | ||||||
14 | Check the thermostat. Refer to Thermostat Diagnosis . Is the thermostat stuck in the closed position? | -- | ||||||
15 | Replace the thermostat. Refer to Engine Coolant Thermostat Replacement . Does the engine overheat? | -- | System OK | |||||
16 | Check for a faulty water pump. Refer to Water Pump Replacement . Are the impeller blades broken or eroded? | -- | ||||||
17 | Check for a missing or damaged radiator upper air deflector and/or center air deflector. Are the deflectors missing or damaged? | -- | ||||||
18 | Check the radiator cooling capacity. Is the proper sized radiator being used on the vehicle? | -- | ||||||
19 | Consult the current parts catalog. If necessary, replace the radiator. Refer to Radiator Replacement . Is the repair complete? | -- | System OK | -- | ||||
