Chevrolet Silverado / GMC Sierra. Service manual — part 1617

Fig. 19: Using Extraction Hose To Draw Out Coolant
Courtesy of GENERAL MOTORS CORP.

27. Use the extraction hose to draw out coolant to the proper level.

28. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain

coolant from the vacuum tank into a suitable container for disposal.

COOLING SYSTEM DRAINING AND FILLING (STATIC FILL)

Special Tools

J 26568 Coolant and Battery Tester

J 38185 Hose Clamp Pliers

Draining Procedure

1. Follow the steps below in order to remove the surge tank fill cap:

1. Slowly rotate the cap counterclockwise.

CAUTION: To avoid being burned, do not remove the radiator cap or

surge tank cap while the engine is hot. The cooling system
will release scalding fluid and steam under pressure if
radiator cap or surge tank cap is removed while the engine
and radiator are still hot.

2008 Chevrolet Silverado 1500

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

2. Stop rotating and allow the hissing to stop.

3. After all the hissing stops, continue turning counterclockwise in order to remove the

cap.

2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

3. Place a drain pan under the lower radiator hose.

4. Using the J 38185 , reposition the lower radiator hose clamp.

5. Remove the lower radiator hose from the radiator.

6. Drain the cooling system.

Fig. 20: View Of Engine Coolant Drain Hole Plug
Courtesy of GENERAL MOTORS CORP.

7. If a complete engine block drain is required, remove the left and right engine block coolant

drain plugs.

2008 Chevrolet Silverado 1500

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

8. Remove the engine block coolant heater, if equipped. Refer to Coolant Heater

Replacement (LH6, LY2, LMG, LY5, and LY6) or Coolant Heater Replacement
(L76, L92).

9. Inspect the coolant.

10. Follow the appropriate procedure based on the condition of the coolant:

Normal in appearance-Follow the filling procedure.

Discolored-Follow the flush procedure. Refer to Flushing .

Filling Procedure

1. Install the lower radiator hose to the radiator.

2. Using the J 38185 , reposition the lower radiator hose clamp.

3. If the left and right engine block coolant drain plugs were removed, perform the following:

1. Apply pipe sealer to the drain plugs.

2. Install the drain plugs.

Tighten: Tighten the drain plugs to 60 N.m (44 lb ft).

4. Install the engine block coolant heater, if equipped. Refer to Coolant Heater

Replacement (LH6, LY2, LMG, LY5, and LY6) or Coolant Heater Replacement
(L76, L92).

5. Lower the vehicle.

6. Slowly fill the cooling system with a 50/50 coolant mixture. Refer to Approximate Fluid

Capacities .

7. Install the coolant pressure cap.

8. Start the engine.

NOTE:

The procedure below must be followed. Improper coolant level
could result in a low or high coolant level condition, causing
engine damage.

NOTE:

Refer to Fastener Notice .

IMPORTANT: Use a 50/50 mixture of DEX-COOL antifreeze and clean,

drinkable water.

2008 Chevrolet Silverado 1500

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

9. Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.

Engine should reach an operating temperature of 90°C (194°F) and the upper radiator hose
should be HOT.

10. Allow the engine to idle for 3 minutes.

11. Shut the engine OFF.

12. Allow the engine to cool.

13. Top off the coolant as necessary.

14. Inspect the concentration of the engine coolant using the J 26568 .

15. Rinse away any excess coolant from the engine and the engine compartment.

FLUSHING

IMPORTANT:

Do not use a chemical flush.

Store used coolant in the proper manner, such as in a used
engine coolant holding tank. Do not pour used coolant down
a drain. Ethylene glycol antifreeze is a very toxic chemical.
Do not dispose of coolant into the sewer system or ground
water. This is illegal and ecologically unsound.

Various methods and equipment can be used to flush the
cooling system. If special equipment is used (such as a back
flusher) follow the manufacturer's instructions. However,
always remove the thermostat before back flushing the
system.

1. Block the drive wheels.

2. Place the transmission in park (P) or neutral (N).

3. Engage the park brake.

4. Run the engine until the thermostat opens.

5. Stop the engine.

6. Follow the drain and fill procedure unsing only clean

drinkable water. Repeat the procedure if necessary, until the
fluid is nearly colorless. Refer to Cooling System Draining
and Filling (Vac-N-Fill) or Cooling System Draining and
Filling (Static Fill).

2008 Chevrolet Silverado 1500

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