Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Inspect for a loss of coolant. Is there a loss of coolant? | -- | ||
2 | Refer to Loss of Coolant. Fill the system to the specified level, then retest. Does the engine overheat? | -- | System OK | |
3 | Inspect for a faulty engine coolant temperature (ECT) sensor. Is the sensor operating properly? | -- | ||
4 | Inspect for a loss of system pressure. Refer to Cooling System Leak Testing . Is there a loss of system pressure? | -- | ||
5 | Inspect for a low coolant concentration level. Refer to Coolant Concentration Testing . Is the coolant concentration low? | -- | ||
6 | Repair or install new parts as necessary, then retest. Does the engine overheat? | -- | System OK | |
7 | Inspect for incorrect drive belt tension. Refer to Drive Belt Tensioner Diagnosis in Engine Mechanical 4.3L. Is the belt tension correct? | -- | ||
8 | Inspect for retarded ignition timing. Is the timing retarded? | -- | ||
9 | Inspect for an obstructed radiator air flow or bent fins. Refer to Radiator Replacement (Inspection). Is the radiator air flow obstructed? | -- | ||
10 | Inspect for a pinched or leaking coolant recovery reservoir hose. Refer to Coolant Recovery System Description . Is the reservoir hose OK? | -- | ||
11 | Inspect for an inoperative cooling fan. Refer to Fan Clutch Diagnosis . Is the fan operating properly? | -- | ||
12 | Inspect the coolant thermostat. Refer to Thermostat Diagnosis . Does the thermostat fail to open or open too late? | -- | ||
13 | Inspect for a faulty water pump. Refer to Water Pump Test. Is the water pump operating properly? | -- | ||
14 | Inspect for a loose, damaged or missing air deflector. Is this system OK? | -- | ||
15 | Inspect the radiator cooling capacity. Is the radiator the specified one for the vehicle accessory package (including aftermarket items)? | -- | ||
16 | Does the overheating occur only when pulling a trailer? Is the trailer weight, plus the vehicle weight less than the GCWR for the vehicle? | -- | ||
17 | Does the overheating occur with prolonged idling (especially with the AC ON)? | -- | -- |
