For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: Engine temperature lamp comes ON and stays ON, or the temperature gage 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? | -- | Go to Step 2 | Go to Step 3
2 | Refer to Loss of Coolant Does the engine still overheat? | -- | Go to Step 3 | System OK
3 | Check for a loss of system pressure. Use the J 24460-01 . Is there a loss of system pressure? | -- | Go to Step 4 | Go to Step 5
4 | Correct the system pressure. Does the engine still overheat? | -- | Go to Step 5 | System OK
5 | Check for low coolant protection. Use the J 23688 . Is the low coolant protection at or above the specified value? | -37 C (-34F) | Go to Step 7 | Go to Step 6
6 | Correct as necessary. Does the engine still overheat? | -- | Go to Step 7 | System OK
7 | Check for an inoperative cooling fan. Refer to Cooling System Description and Operation Are there any inoperative cooling fans? | -- | Go to Step 8 | Go to Step 9
8 | Repair or replace the electric cooling fans as necessary. Refer to Cooling Fan Inoperative Does the engine still overheat? | -- | Go to Step 9 | System OK
9 | Check the drive belt tension. Check the drive belt tensioner. Is the tensioner working properly and is the tension correct? | -- | Go to Step 11 | Go to Step 10
10 | Replace the tensioner as necessary. Refer to Drive Belt Tensioner Replacement in Engine Mechanical 3.0L. Does the engine still overheat? | -- | Go to Step 11 | System OK
11 | Check for a cracked coolant recovery reservoir or a leaking hose. Is the reservoir cracked or is the hose leaking? | -- | Go to Step 12 | Go to Step 13
12 | Repair or replace part(s) as necessary. Does the engine still overheat? | -- | Go to Step 13 | System OK
13 | Check for a faulty auxiliary water pump. Is an auxiliary water pump faulty? | -- | Go to Step 14 | Go to Step 15
14 | Repair or replace the auxiliary water pump. Refer to Auxiliary Water Pump Replacement . Does the engine still overheat? | -- | Go to Step 15 | System OK
15 | Check for a faulty engine coolant temperature (ECT) sensor. Refer to Cooling System Description and Operation . Is the sensor operating properly? | -- | Go to Step 17 | Go to Step 16
16 | Replace the Engine Coolant Temperature (ECT) sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls 3.0L. Is the engine still overheating? | -- | Go to Step 17 | System OK
17 | Check for obstructed radiator air flow or bent radiator fins. Is the radiator air flow obstructed? | -- | Go to Step 18 | Go to Step 19
18 | Remove or relocate any add-on parts that block air to the radiator. Remove any debris from the radiator fins. Does the engine still overheat? | -- | Go to Step 19 | System OK
19 | Check the thermostat. Refer to Thermostat Diagnosis . Is the thermostat stuck in the closed position? | -- | Go to Step 20 | Go to Step 21
20 | Replace the thermostat. Refer to Engine Coolant Thermostat Replacement . Does the engine overheat? | -- | Go to Step 21 | System OK
21 | Check for blocked cooling system passages. Are the cooling system passages blocked? | -- | Go to Step 22 | Go to Step 23
22 | Drain the cooling system. Refer to Cooling System Draining and Filling . Flush the cooling system. Refer to Flushing . Does the engine overheat? | -- | Go to Step 23 | System OK
23 | Check for a faulty engine water pump. Are the impeller blades broken or eroded? | -- | Go to Step 24 | Go to Step 25
24 | Replace the water pump. Refer to Water Pump Replacement . Does the engine still overheat? | -- | Go to Step 25 | System OK
25 | Check the radiator cooling capacity. Is the proper sized radiator being used on the vehicle? | -- | Go to Diagnostic System Check - Engine Cooling | Go to Step 26
26 | Replace the radiator. Refer to Radiator Replacement . Is the repair complete? | -- | System OK | --