Burping the radiator?!??!?!?

[PCNWSUBARU]

What exactly does burping the system entail. My 1997 Legacy wagon was overheating. Put in a new water pump, thermostat, timing belt and radiator. After doing all that it ran fine for about a week and then began overheating again. I tried releasing the pressure valve on the radiator and letting it run. I read on here that someone thought itd be a good idea to burp the system in a similar situation. Any ideas or thoughts would be most helpful

[xoSubieLegacyxo]

You're supposed to "burp" the system whenever you change a part on the coolant system, or when a coolant line is open. What you do is replace all the necessary parts on the cooling system, fill the system with coolant, and leave the radiator cap OFF. Then turn the key and start the engine. What you are trying to do is when the system kicks on the coolant will run through the lines of the engine, and return to the radiator where any air will "burp" or release out of the radiator cap. Hope this helps!

[Garrison]

Conversely, you fill with fluid, leave the cap open, and squeeze the tube going to the engine. You'll see little bubbles coming from the cap-opening, and the level of coolant will go down. Fill with fluid. Repeat until there are no more bubbles.

You don't really want to start the car with air in the system.

[xoSubieLegacyxo]

We just took out the radiator and put it back in the car I worked on in the college shop. It was a Scion xB, and we ran the engine until the coolant cycled through the block. That was the only time I ever did it so someone else might have a better way of burping the system.

[Garrison]

Now that you mention it, I've seen another guy do that on a radiator replacement.

Hmm, perhaps I'm being too careful?

[mlitz]

Also on legacy's there is a bleeder screw on the top passenger side of the radiator that will make the job 100 times easier.

EDIT:
oh also if you jack up the driver side corner (the side with the cap) and make it the highest part of the cooling system it could help too.

[rougeben83]

Now that you mention it, I've seen another guy do that on a radiator replacement.

Hmm, perhaps I'm being too careful?

You do both, run the engine until it reaches operating temp so the thermostat opens and circulates coolant through the system, squeezing the top hose in the process to work out any airbubbles that may be trapped.