Purging air from cooling system

[my996]

I will be replacing the overflow coolant tank in my 99 999 C4. I was comfortable using the method described in a thread on the board that describes the process - using the relief value and purging air by a combination of opening the value and letting and cool, etc. etc. However, when I had my car at the shop to replace the alternator the other day, porsche mechanic said the only way to purge the air is to use a pressure system. I think he just wants me to pay him to do it but just in case - Loren, or anyone who might know, what is the correct way to remove the air from the cooling system once I have reinstalled the expansion coolant tank? Thanks

[Loren]

Well if the whole system has been emptied then the best way is to use a vacuum (pull) to fill the system and eliminate air.

If you just added a 3rd radiator or replaced the coolant tank then you should not have lost much coolant - in that case I have found the driving with the purge valve open works fine.

[my996]

Well if the whole system has been emptied then the best way is to use a vacuum (pull) to fill the system and eliminate air.

If you just added a 3rd radiator or replaced the coolant tank then you should not have lost much coolant - in that case I have found the driving with the purge valve open works fine.

anyway to tell if there is air in the system? - also, if I wanted to be anal about this, where can I can a vacuum pump that will help me do this? Any cost ideas?

[Loren]

The usual way that you know there is air in the system is higher than normal temps and having to refill the coolant tank.

Here is the vacuum refiller...

http://www.renntech.org/forums/index.php?s...ost&p=64529