Confused about coolant venting

[Belgian951]

I've read tons of topics on how to vent the coolant system on a 944 turbo, but I managed to still be confused.

Is the venting done when the coolant is hot or not? There seems to be a rule never work on a hot system to vent it, but at the same time i'm reading things like "open the vent screw and let steam escape".

I'm using a pressure vent method with 10 psi of pressure applied.

[Tom]

The low-tech way is to let the motor warm up completely, then crack the vent while the motor is still running to let out steam; then close the vent and drive around the block and do it again; then rinse and repeat until no air is left. If you have a pressure tester, you can vent the motor while cold. Apply 10-15psi at the reservoir and then crack the vent screw until it has a solid flow and isn't spitting air/coolant. You may need to do that a few times too, after driving it, as air can get trapped sometimes. A wet/dry shop vac can help keep the motor clean while venting. Assuming no head gasket leaks, the last few bubbles of air should work their way out while driving over time. If you can hear a lot of gurgling when you turn the heater on; or if the engine temp rises at stop lights and then drops quickly when you get going again; those are sure signs that you need to vent more.

[Belgian951]

Thanks once again Tom!

[netopier]

beware, that if the air is trapped near 4th cylinder in the head, it can cause headgasket failure, that is why steam vent kit was invented and used. i see the vacuum method as the only one, which can avoid this