00 Sierra 4.8l Question

[dannyo210]

Hi, I just replaced the thermostat in my 2000 4.8L Sierra, following the Haynes manual. I am having issues with the engine overheating however, and I believe there is air in the system.

 

I was hoping somebody has an easy solution to bleeding the coolant system to relieve the air, so I will not have to spend another $25 on DEXCOOL after draining it all again.

 

Any advice would be appreciated.

 

Thanks

[jackyshaikh]

Follow this procedure

 

<A href="http://gsi.xw.gm.com/si/cellHandler.do?cellId=37226&refDoc=523204&from=sm#ss1-523104">

Drain and Fill Procedure

Important: If you do not follow the procedure below, a low or high coolant level condition and/or vehicle damage could result.

 

 

1. 
   <LI type=1>Park the vehicle on a level surface. <LI type=1>Follow the steps below in order to remove the radiator surge tank fill cap:

• Slowly rotate the cap counterclockwise.

 

 

• Stop rotating and allow the hissing to stop.

 

 

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

 

<LI type=1>Remove the drain hose from the left side of the radiator tank and repositon the hose to a catch pan. <LI type=1>Open the radiator drain cock. <LI type=1>Allow the system to drain completely. <LI type=1>Inspect the engine coolant:

• Discolored -- follow the flush procedure below.

 

 

• Normal in appearance -- Continue with the next step.

 

<LI type=1>Close the radiator drain cock. Important: When filling the cooling system use a 50 to 60 percent concentration with DEX-COOL® coolant.
 
<LI type=1>Fill the system through the radiator surge tank opening. <LI type=1>Pre-mix a 50 to 60 percent solution of DEX-COOL® and clean, drinkable water. <LI type=1>Slowly add the pre-mixed solution to the system until the level is slighlty above the surge tank split line. <LI type=1>Start the engine. <LI type=1>Idle the engine for 1 minute. <LI type=1>Loosely install the surge tank cap. Do not allow the system to build pressure. <LI type=1>Cycle the engine from idle to 3000 RPM in 30 seconds intervals until the engine coolant reaches 99°C (210°F) and the thermostat opens. <LI type=1>Shut off the engine. <LI type=1>Refer to step 3 in order to remove the radiator surge tank cap. <LI type=1>Start the engine. <LI type=1>Idle the engine for 1 minute. Fill the surge tank to ½ inch above the COLD FULL mark on the radiator surge tank. <LI type=1>Install the radiator surge tank cap. <LI type=1>Cycle the RPM. Idle the engine to 3000 in 30 second intervals until the engine coolant reaches 99°C (210°F). <LI type=1>Shut off the engine. <LI type=1>Top off the coolant, as necessary, to ½ inch above FULL COLD mark on the radiator surge tank. <LI type=1>Rinse away any excess coolant from the engine and the compartment.

Inspect the concentration of the coolant.

1. 
   
   

 

[merlin5577]

Hi, I just replaced the thermostat in my 2000 4.8L Sierra, following the Haynes manual. I am having issues with the engine overheating however, and I believe there is air in the system.

 

I was hoping somebody has an easy solution to bleeding the coolant system to relieve the air, so I will not have to spend another $25 on DEXCOOL after draining it all again.

 

Any advice would be appreciated.

 

Thanks

 

I dont mean to be a jerk by saying this but.......RTFM.

 

If you look in the manual it will (or should, at least in every GM vehicle I have ever owned or worked on) tell you were the bleed valve(s) for the cooling system is/are. Just open the valve(s) and let the air out. Good luck.