[AKnowles]

Jager, for my two cents I would not open the reservoir while it is hot. Before I bought my uvIew Airlift 550000 for the vacuum bleed I did several flushes using just distilled water. Anytime I tried to open the reservoir there was venting. Even with the purge valve open. I'd recommend letting it cool. Doesn't have to be completely cool, but can't be at operating temperature.

If you are in Southern CA, you are welcome to stop by and use my vacuum system. After my first fill, and running the motor, I let it cool down and created a vacuum again and added another 1/2 gallon using the system. Since then it has been running at normal temps. I seriously recommend buying a vacuum system for the coolant flush or water pump replacement as it works very well and eliminates the need to bleed the system.