Heater Valve: Car off, does it default to open?
 

OK, here's a question, when the car is not running, is the vacuum operated heater valve in the open position or closed?

I picked up a Stant cooling system pressure tester (amazing tool by the way) and when I use it to bleed the system, I want to be sure I'm getting to the heater core as well.

Thanks guys.

You need the car running and at operting temp to properly bleed the cooling system. I also helps to raise the front of the car a bit when doing the bleed. Heater valve must be OPEN when bleeding.

If you don't have the car running and at operating temp you will not get all the air out of the system. There is a pocket in the back of the head that traps air, and if not properly bled, you will end up with a "hot spot" and ultimately a blown head gasket.

Proper bleeding of the system is another one of the "MUST DO" things on these cars, just like timely timing/balance belt replacement.

Under the hood is in pieces, I've just built up the coolant system with all new hoses and want to check for leaks before I assemble much more. Its easy to get to the hoses now if I need to tighten or adjust. I'll do a full nose up hot bleed in the spring.

I'm pretty sure the valve is open if there is no vacuum to it. With the car off, the coolant should go through the valve, not sure about the heater core ( exchanger) though. I would suspect that it does.

Thanks, that seems logical to me, but I've been fooled before by illogical occurences on my 951.

Without even seeing the pressure tester, I must agree that it is amazing, if it can also be used to bleed the system out. Looks like you have your answer, anyways.