GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Chevy C Cab/Chassis HD (GMT 400) 🢒 Engine 🢒 Engine Cooling 🢒 Engine Overheating

Step

Action

Yes

No

1

Inspect for a loss of system pressure.

Is there a loss of system pressure?

Go to Step 2

Go to Step 3

2

Inspect and repair any faulty hose connections.

Does the engine still overheat?

Go to Step 3

System OK

3

Inspect for low coolant protection (-37°C/-34°F).

Is low coolant protection present?

Go to Step  4

Go to Step 5

4

Replace the coolant. Refer to Cooling System Draining and Filling .

Does the engine still overheat?

Go to Step 5

System OK

5

Inspect the drive belt for excessive wear or low tension.

Is the drive belt worn or is the tension too low?

Go to Step 6

Go to Step 7

6

Replace the drive belt. Refer to Drive Belt Replacement in Engine Mechanical - 8.1L.

Does the engine still overheat?

Go to Step 7

System OK

7

Inspect the water pump.

Is the water pump inoperative?

Go to Step 8

Go to Step 9

8

Replace the water pump. Refer to Water Pump Replacement .

Does the engine still overheat?

Go to Step 9

System OK

9

Inspect the radiator fins for obstruction.

Are the radiator fins obstructed?

Go to Step 10

Go to Step  11

10

Inspect and clean the radiator. Refer to Radiator Cleaning .

Does the engine still overheat?

Go to Step 11

System OK

11

Inspect the cooling system passage for obstruction.

Is the cooling system passage blocked?

Go to Step 12

Go to Step 13

12

Inspect and flush the system. Refer to Flushing .

Does the engine still overheat?

Go to Step 13

System OK

13

Insepct the fan clutch. Refer to Fan Clutch Diagnosis .

Is the fan clutch inoperative?

Go to Step 14

Go to Step 15

14

Replace the fan clutch. Refer to Fan Clutch Replacement .

Does the engine still overheat?

Go to Step 15

System OK

15

Inspect for a stuck thermostat. Refer to Thermostat Diagnosis .

Is the thermostat stuck in the closed position?

Go to Step 16

Go to Step 17

16

Replace the thermostat. Refer to Engine Coolant Thermostat Replacement .

Does the engine still overheat?

Go to Step 17

System OK

17
  1. The following factors may cause the engine to overheat:
    2. • A heavy vehicle payload
    • Excess engine oil
    • Restricted air flow through the radiator
    • Extreme air temperature
  2. Correct or repair as necessary.

Does the engine still overheat?

--

System OK