vacuum coolant fill
 

Is there a visual reference to know when you have reached the correct amount of vacuum necessary to start the vacuum coolant fill process? For example the coolant hose lines are collapsed?
If I had a vacum gauge the reading should be 25 but I don't have a gauge.
When is too much vacuum and when is not enough?

There is no visual reference, you should have a gauge, and should be pulling 23-27 inches of vacuum. It is common for the hoses to collapse well before that level of vacuum is reached. And there is no "too much vacuum" level, you need to get all the air out and have enough vacuum to pull in the new coolant.

What kind of vacuum fill system are you using that does not have a proper gauge?

JFP,
Its an oil extraction (Pela 6000) hand pump adapted to suck air. I read about it on this site How To Vacuum Refill Coolant System using a Pela 6000 and a Rubber Bung - MG-Rover.org Forums.
I just tested it on the car, no coolant and after 27 strokes of the pump it collapsed the large coolant hoses under the car. I clamped off the pump hoses for 3 min. and the vacuum held. When I realeased the clamp and put my finger over the end of the hose I was surprised at the amount of suction.
If you apply too much suction is there any fear of ruining seals?

Since I didn't hear back from anyone I went ahead and used my hand vacum pump. It worked great just not long enough, haaaa! I was still concerned about creating too much of a vacum so after about 85 - 90 strokes I stoped pumping and allowed the coolant to flow into the engine.
Too soon, I got about 4-4.5 gallons in, now I'll have to do the remainder the burp method. It worked well I just didn't create enough vacuum.
I think a gauge would have made the difference. The pumping action was getting a little harder but still lots of stroke remaining.

The 5 gallon bucket has the new coolant mix.
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