For 1990-2009 cars

Step | Action | Value | Yes | No
--- | --- | --- | --- | ---
DEFINITION: The engine temperature lamp comes on and stays on, or the temperature gauge shows hot, or coolant overflows from the coolant recovery 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 | Fill the system to the specified level. Refer to Loss of Coolant . Does the engine still overheat? | -- | Go to Step 3 | System OK
3 | Check for a missing or damaged radiator upper air deflector, baffle, or center air deflector. Are there any missing or damaged deflectors or baffles? | -- | Go to Step 4 | Go to Step 5
4 | Repair or replace any deflectors or baffles as necessary. Does the engine still overheat? | -- | Go to Step 5 | System OK
5 | Check the coolant concentration. Refer to Coolant Concentration Testing . Is the coolant concentration adequate? | -- | Go to Step 7 | Go to Step 6
6 | Correct the coolant concentration as necessary. Refer to Notice: Pure coolant can be added to raise the boiling point of the coolant, but too much will affect the freezing point. Do not use a solution stronger than 70 percent, as the freeze level rises rapidly after this point. Pure coolant will freeze at -22°C (-8°F). .

Does the engine still overheat?

--

Go to Step 7

System OK

7 | Check for a loss of cooling system pressure. Does the cooling system maintain the correct pressure? | -- | Go to Step 9 | Go to Step 8
8 | Pressure test the cooling system. Correct as necessary. Refer to Radiator Diagnosis . Does the engine still overheat? | 103 kPa (15 psi) | Go to Step 9 | System OK
9 | Check for a pinched or kinked coolant recovery reservoir hose. Is the reservoir hose kinked or damaged? | -- | Go to Step 10 | Go to Step 11
10 | Reroute or replace the hose as necessary. Refer to Coolant Recovery Reservoir Replacement . Does the engine still overheat | -- | Go to Step 11 | System OK
11 |

1. Check the drive belt tension.
2. Check the tensioner. Refer to Drive Belt Tensioner Diagnosis in Engine Mechanical.

Is the tensioner working properly?

--

Go to Step 13

Go to Step 12

12 | Replace the tensioner as necessary.

• | For VIN 1, refer to Drive Belt Tensioner Replacement in Engine Mechanical.

• | For VIN K, refer to Drive Belt Tensioner Replacement in Engine Mechanical.

Does the engine still overheat?

--

Go to Step 13

System OK

13 | Check for an obstructed radiator air flow or bent fins. Are any radiator fins bent or is air flow to the radiator being obstructed? | -- | Go to Step 14 | Go to Step 15
14 | Remove or relocate add on parts that block air flow to the radiator. Refer to Cooling System Maintenance Recommendations . Does the engine still overheat? | -- | Go to Step 15 | System OK
15 | Check for a blockage in the cooling system passages. Are the cooling system passages blocked? | -- | Go to Step 16 | Go to Step 17
16 |

1. Drain the coolant. Refer to Cooling System Draining and Filling .
2. Flush the cooling system. Refer to Flushing .
3. Repair as necessary.

Does the engine still overheat?

--

Go to Step 17

System OK

17 | Check for an inoperative cooling fan. Refer to Electric Cooling Fan Diagnosis in Engine Controls. Are any cooling fans inoperative? | -- | Go to Step 18 | Go to Step 19
18 | Repair or replace the cooling fan as necessary. Refer to Electric Cooling Fan . Does the engine still overheat? | -- | Go to Step 19 | System OK
19 | Check if the thermostat is stuck in the closed position. Refer to Thermostat Diagnosis . Is the thermostat sticking (or stuck) in the closed position? | -- | Go to Step 20 | Go to Step 21
20 | Replace the thermostat as necessary. Refer to Engine Coolant Thermostat Replacement . Does the engine still overheat? | -- | Go to Step 21 | System OK
21 | Check for a faulty coolant pump. Is the coolant pump faulty? | -- | Go to Step 22 | System OK
22 | Replace the coolant pump as necessary.

1. On the 3.8L (L67) engine, refer to Water Pump Replacement .
2. On the 3.8L (L36) engine, refer to Water Pump Replacement .

Does the engine still overheat?

--

Go to Step 23

System OK

23 | Check the radiator cooling capacity. Make sure the proper sized radiator is being used on the cooling system. Is the correct sized radiator being used with the cooling system? | -- | System OK | Go to Step 24
24 | If necessary, install the correct radiator. Refer to Radiator Replacement . Does the engine still overheat? | -- | -- | System OK