Coolant System Bleeding

[bfloyd]

I've finally gotten my car to the point where it will consistently start just about every time I turn the key. I've only been running it for a couple of minutes at a time, and probably not long enough for the thermostat to open. I have replaced the entire cooling system (new hoses, new coolant bottle, new water pump, and a new radiator), and have installed the "Wings Be Cool" bleeding kits at both the front and rear of the car. I've filled the system up with antifreeze, pressure tested it with no leaks, and now I'm to the point where I know I'll need to bleed the trapped air out of the system.

Might be stupid question, but nothing is going to be able to bleed until the thermostat opens, right? I have the engine running this afternoon, and crawled up under the right front wheel to turn the bleeder valve. Nothing came out. No air, just nothing. Do I just need to wait a little longer for the thermostat to open before I can proceed with the bleeding? The temperature gauge in the car doesn't move... or hasn't moved yet.

Can someone give me a little advise on what to expect?

[AugustneverEnds]

Congratulations on accomplishing an important overhaul!! :thumbup2:

You got it right, until the engine begins to heat up and the thermostat opens no coolant or air will bled out of the system. You need to let the engine run until the gauge is a bit over the first mark and the fans kick on and make sure the climate control knob is pointed to HEATER and the temperature knob is set to full HOT to properly bleed the heater core. Bleed the radiator first and then the engine. It helps to have a helper to keep track of how hot everything is getting to avoid overheating and drawing air back in. Since you have replaced so many parts don't be alarmed or discouraged if it takes more than one round of bleeding to get it done. Just for full disclosure I don't use the self-bleeder kits so I don't have experience with them.

[David T]

Congratulations on accomplishing an important overhaul!! :thumbup2:

You got it right, until the engine begins to heat up and the thermostat opens no coolant or air will bled out of the system. You need to let the engine run until the gauge is a bit over the first mark and the fans kick on and make sure the climate control knob is pointed to HEATER and the temperature knob is set to full HOT to properly bleed the heater core. Bleed the radiator first and then the engine. It helps to have a helper to keep track of how hot everything is getting to avoid overheating and drawing air back in. Since you have replaced so many parts don't be alarmed or discouraged if it takes more than one round of bleeding to get it done. Just for full disclosure I don't use the self-bleeder kits so I don't have experience with them.

The thermostat is supposed to have a small hole in it to allow air to pass so you CAN bleed it. For the initial bleed fill the header bottle and pressurize the system. Open the bleeder by the thermostat and let it go until all of the air is out. Refill the header bottle and repressurize. Loosen the small hose on the top, right side of the radiator and let the air out of it. Tighten the hose and check the header bottle is 1/2 full. You may have to repeat again. Drive the car and check the coolant level frequently till you are sure you got all the air out and there are no leaks. Make sure the fans start up. Should not take more than 20 minutes. Verify they run when you turn on the A/C. You do not need to have the heater on, it is on ALL THE TIME except when in MAX. You should not need any of the auto bleeder kits. If you have no leaks, didn't pop the head gaskets by overheating the motor, and you completely bled the system, any remaining trapped air will work itself out.

[Chris4099]

As David mentioned, there should be a small hole in the thermostat that will let air out of the engine as you fill. I've had that kit for years and what I do is fill the system to the top and let air out at the front bleeder by the radiator. Move it as high as possible to reduce the amount of coolant that comes out with the air. Once nothing but coolant comes out, close the valve. Go back to the expansion tank and top off. I just did this last week and the tank was completely empty which shows how much air is trapped at the radiator! Now you can go ahead and start the car. Any remaining air should come out on its own thanks to the self bleeder. Usually what's left is just enough to bring the level down in the expansion tank back to normal. If there's too much coolant, it will simply purge itself out once the system fully heats up.