GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The engine temperature lamp comes on and stays on, 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.

Has there been 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 .

Has there been 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 or J 26568 .

Is the low coolant protection at or above the specified value?

-37°C (-34°F)

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 Fan Inoperative .

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 Engine Cooling Fan Replacement .

Does the engine still overheat?

--

--

Go to Step 9

9

  1. Check the accessory drive belt tension.
  2. Check the tensioner.

Is the tensioner working properly and the tension correct?

--

Go to Step 11

Go to Step 10

10

Replace the tensioner as necessary. Refer to one of the following procedures:

    •  Drive Belt Tensioner Replacement in Engine Mechanical - 3.1L
    •  Drive Belt Tensioner Replacement in Engine Mechanical - 3.8L

Does the engine still overheat?

--

Go to Step 11

System OK

11

Check to see if any of the radiator fins are obstructed.

Are any of radiator fins obstructed?

--

Go to Step 12

Go to Step 13

12

  1. Remove or relocate any add-on parts that block air to the radiator.
  2. Remove any debris from the radiator fins.

Does the engine still overheat?

--

Go to Step 13

System OK

13

Check to see if any of the cooling system passages are blocked by rust or scale.

Are any of the cooling system passages blocked by rust or scale?

--

Go to Step 14

Go to Step 15

14

  1. Drain the cooling system. 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 15

System OK

15

Check for a pinched or kinked coolant recovery reservoir hose.

Is the reservoir hose pinched or kinked?

--

Go to Step 16

Go to Step 17

16

Replace or reroute the hose as necessary. Refer to Coolant Recovery Reservoir Replacement .

Does the engine still overheat?

--

Go to Step 17

System OK

17

Check for a loose, damaged, and/or missing deflector.

Are there any loose, damaged, or missing deflectors?

--

Go to Step 18

Go to Step 19

18

Replace the deflectors. Refer to Radiator Air Baffle Assemblies and Deflectors .

Does the engine still overheat?

--

Go to Step 19

System OK

19

Check to see if the thermostat is stuck in the closed position.

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 still overheat?

--

Go to Step 21

System OK

21

Check for a faulty water pump.

Is the water pump faulty?

--

Go to Step 22

Go to Step 23

22

Replace the water pump. Refer to Water Pump Replacement .

Does the engine still overheat?

--

Go to Step 23

System OK

23

Check for an incorrect radiator.

Is the radiator correct?

--

Go to Step 24

--

24

Install the correct radiator. Refer to Radiator Replacement .

Does the engine still overheat?

--

--

System OK