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J 26568 - Coolant and Battery Fluid Tester
J 42401 - Radiator Cap and Surge Tank Test Adapter
GE-47716 - Vac-N-Fill Coolant Refill Tool
Draining Procedure

Warning

With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.

Remove the coolant pressure cap.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (See: Maintenance\Vehicle Lifting\Service and Repair).
Place a drain pan under the drain cock.
Remove the radiator drain cock.
Drain the cooling system.
Lower the vehicle.
Inspect the coolant.
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 (See: Flushing).
Vac-N-Fill Procedure

Install the J 42401 - Radiator Cap and Surge Tank Test Adapter onto the coolant surge tank.

Warning

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.

Attach the Vac-N-Fill cap to the J 42401 - Radiator Cap and Surge Tank Test Adapter.

Attach the vacuum gauge assembly to the Vac-N-Fill cap.

Attach the fill hose to the barb fitting on the vacuum gauge assembly. Ensure that the valve is closed.

Note: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water.

Always use more coolant than necessary. This will eliminate air from being drawn into the cooling system.

Pour the coolant mixture into the graduated reservoir.
Place the fill hose in the graduated reservoir. Note: Prior to installing the vacuum tank onto the graduated reservoir, ensure that the drain valve located on the bottom of the tank is closed.
Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.

Attach the venturi assembly to the vacuum tank.

Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.

Attach the vacuum hose to the vacuum gauge assembly and the vacuum tank.

Open the valve on the venturi assembly. The vacuum gauge will begin to rise and a hissing noise will be present.

Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg). Cooling hoses may start to collapse. This is normal due to vacuum draw.
To aid in the fill process, position the graduated reservoir above the coolant fill port.

Slowly open the valve on the vacuum gauge assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
Close the valve on the venturi assembly.
If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss. If vacuum loss is observed, refer to Loss of Coolant (See: Testing and Inspection\Symptom Related Diagnostic Procedures\Loss of Coolant).
Open the valve on the vacuum gauge assembly. The vacuum gauge will drop as coolant is drawn into the system.

Once the vacuum gauge reaches zero, close the valve on the vacuum gauge assembly and repeat steps 11-17.
Detach the Vac-N-Fill cap from the J 42401 - Radiator Cap and Surge Tank Test Adapter.
Remove the J 42401 - Radiator Cap and Surge Tank Test Adapter from the coolant surge tank.
Add coolant to the system as necessary.
Inspect the concentration of the coolant mixture using J 26568 - Coolant and Battery Fluid Tester. Note: After filling the cooling system, the extraction hose can be used to remove excess coolant to achieve the proper coolant level.
Detach the vacuum hose from the vacuum gauge assembly.

Attach the extraction hose to the vacuum hose.

Open the valve on the venturi assembly to start a vacuum draw.

Use the extraction hose to draw out coolant to the proper level.
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.
Install the surge tank cap.

Best way to bleed any cooling

Submitted by Big Block 409 on Sat, 06/04/2011 - 14:09.

Best way to bleed any cooling system on any vehicle is to install a "Prestone Flush and Fill" kit. Question is, why do you think it's necessary to bleed the system on your Camaro? What sort of cooling system problem are you havin? Also how did you come to the resolution, that bleedin the system is gonna fix the problem?

I recently did a cam swap,

Submitted by tiwanaku on Sat, 06/04/2011 - 15:03.

I recently did a cam swap, which as you know involves removing the water pump and timing chain cover. I can only assume I have air still trapped in the system as it will not pressurize. I can open the cap with the engine temp at 225F and not lose coolant. I have already replaced the cap in hopes that it was faulty, but this did nothing to address the issue.

Attempting to fix the issue before heading back to the dyno. Thank you for the input. If you can think of any other cause for the system not pressurizing and point me in the proper direction, that will be greatly appreciated. I believe that I am on the right track, but I have never had an issue purging air or getting pressure before.

you'll still need to apply

Submitted by mws919 on Sat, 06/04/2011 - 15:00.

you'll still need to apply vacuum to remove the air, on this system.

Air pocket Water pump

Submitted by Big Block 409 on Sat, 06/04/2011 - 15:24.

Air pocket
Water pump problem
Wrong radiator cap
Thermostat stuck open

it's a closed loop system, so

Submitted by mws919 on Sat, 06/04/2011 - 16:03.

it's a closed loop system, so any trapped air cann't get out, that's why gm has this tool to remove the trapped air.
with out building enogh pressure the fluid will come to boil at a lower temp.
i work for the dealer, so have only used thier tool, but i'm sure it must be avil. on after market by now.
call some part stores and ask if they carry it or rent it.