Chevrolet Silverado / GMC Sierra. Service manual — part 1610

Go to Step 2 Cooling

2

Repair any present DTCs. Refer to Diagnostic
System Check - Vehicle .
Is the action complete?

Go to Step 3

-

3

Inspect the coolant level.
Is the coolant at the proper level?

Go to Step 5

Go to Step 4

4

Fill the cooling system to the proper level. Refer
to Cooling System Draining and Filling
(Vac-N-Fill) or Cooling System Draining
and Filling (Static Fill).
Is the action complete?

Go to Step 5

-

5

Engine overheating can cause a loss of coolant.
Is the engine overheating?

Go to Step 19

Go to Step 6

6

1. Idle the engine at normal operating

temperature.

2. Inspect for heavy white smoke coming out

of the exhaust pipe.

Is a heavy white smoke present from the exhaust
pipe?

Go to Step 7

Go to Step 8

7

1. Coolant in the exhaust system creates a

distinctive, burning coolant odor in the
exhaust.

2. Condensation in the exhaust system can

cause an odorless white smoke during
engine warm up.

Does the white smoke have a burning coolant
type odor?

Go to Step 20

Go to Step 8

8

Visually inspect the hoses, pipes and hose
clamps.
Are any of the hoses, clamps or pipes leaking?

Go to Step 21

Go to Step 9

Visually inspect the following components:

Block heater

Coolant pressure cap

Core plugs

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

9

Throttle body

Engine block

Intake manifold

Radiator

Thermostat housing

Water pump

Are any of the listed components leaking?

Go to Step 21

Go to Step 10

10

1. Pressure test the cooling system. Refer to

Cooling System Leak Testing.

2. With the cooling system pressurized,

visually inspect the components listed in
steps 7 and 8.

Are any leaks present?

Go to Step 21

Go to Step 11

11

Pressure test the coolant pressure cap. Refer to
Pressure Cap Testing.
Does the coolant pressure cap hold pressure?

Go to Step 12

Go to Step 16

12

Inspect for the following conditions:

A coolant smell inside of the vehicle

Coolant in the HVAC module drain tube

Coolant on the vehicle floor covering near
the HVAC module

Is coolant present?

Go to Step 21

Go to Step 13

13

Inspect the underside of the engine oil fill cap
for a gray/white milky substance.
Is there a milky substance under the oil fill cap?

Go to Step 14

Go to Step 15

14

Inspect the engine oil fluid level indicator for a
gray/white milky substance.
Is there a milky substance on the engine oil fluid
level indicator?

Go to Step 17

Go to Step 15

Inspect the automatic transmission oil fluid level
indicator, if equipped, for a gray/white milky

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

THERMOSTAT DIAGNOSIS

Tools Required

J 24731 Tempil Stick

15

substance.
Is there a milky substance on the automatic
transmission fluid level indicator?

Go to Step 18

Go to Step 22

16

Replace the coolant pressure cap.
Is the repair complete?

Go to Step 22

-

17

1. Replace the radiator. Refer to Radiator

Replacement (4.3, 4.8, 5.3, and 6.0L) or
Radiator Replacement (LLM).

2. Replace the oil and filter. Refer to Engine

Oil and Oil Filter Replacement

Is the repair complete?

Go to Step 22

-

18

1. Replace the radiator. Refer to Radiator

Replacement (4.3, 4.8, 5.3, and 6.0L) or
Radiator Replacement (LLM).

2. Service the automatic transmission. Refer

to the following: Engine Coolant/Water
in Transmission .

Is the repair complete?

Go to Step 22

-

19

Repair the engine overheating condition. Refer
to Engine Overheating.
Is the repair complete?

Go to Step 22

-

20

Repair the engine internal coolant leak. Refer to
Coolant in Combustion Chamber or,
Coolant in Engine Oil .
Is the repair complete?

Go to Step 22

-

21

Repair or replace the leaking component. Refer
to the appropriate repair.
Is the repair complete?

Go to Step 22

-

22

Operate the system in order to verify the repair.
Did you find and correct the condition?

System OK

Go to Step 2

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Use one of the following procedures in testing for a malfunctioning thermostat.

Thermostat Test Procedure Using Tempil Sticks

The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a
pencil like device. It has a wax material containing certain chemicals which melt at a given
temperature. Temperature sticks can be used to determine a thermostat's operating range, by
rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing.

1. Use a tempil stick in order to find the opening and the closing temperatures of the coolant

thermostat.

J 24731 -188 tempil stick melts at 87°C (188°F). The thermostat should begin to open.

J 24731 -206 tempil stick melts at 97°C (206°F). The thermostat should be fully open.

2. Replace the coolant thermostat if it does not operate properly between this temperature

range.

Thermostat Test Procedure Using Glycol

Inspect the operation of the thermostat by hanging the thermostat on a hook in a 50/50 percent
solution of DEX-COOL® and clean drinkable water.

In order to inspect if the thermostat valve is opening properly, perform the following test:

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado