A few cooling system questions

I replaced (well, they are on order for tomorrow) my upper and lower rad hoses today. I back flushed the rad and heater core. Here are my questions, as I have not done this for awhile. This is for my 96 Roady wagon, by the way. First, how much coolant will the system require now that it is basically empty? Secondly, I see what looks like a bleeder valve where the hose connects to the engine in the front. When do I open that, and for how long? Finally, do you guys use a 50/50 blend (premixed) or use 100% coolant and dilute it yourself? Thanks for your help, and feel free to add any nuggets/pearls of wisdom to this discussion so I don't screw anything up!! 

First off, your system is not almost empty, your engine block is almost full and your heater core
has coolent in it. I am going by memory,but I think the big Buick Wags. have about a 16 qt
capacity , but that is an estimate only. I use 50/50,distilled water and Dex-cool anti -freeze. I mix my own,I believe its cheaper to do it that way. Their are notes on bleeding the cooling system that we have. Dont mix anti -freeze types,you should use one kind only.
good luck.

I usually flush everything with water and then add a gallon of 100% coolant. Add maybe a quart more then top off with water. Of course I don't have to worry about freezing where I am, but have not had any cooling issues that way.

As for the bleeder, you open it until coolant squirts out then close it. I just open it a little so you can hear the air escaping and it doesn't soak everything.

I to the 100% strength and dilute with distilled water.  If you pull the block plugs (sensors I believe) you can get more flushing done to the block.  Sometimes it takes time for all the air to work its way to the top.  Keep on eye on the gauge after you begin to run her.  If it get to warm bleed it again.  If you do it sprockets way be very careful you don't get a pocket of wagon in the block.  I have heard of that happening, not good in Pittsburgh.  I usually add some Water Wetter as well.

Thanks for all the tips guys. I filled it and let it run in my driveway with the air on for a half hour, turned it off, and opened the bleeder valve. It worked perfectly, hissing out some air for maybe 4-5 seconds. After it completely cooled down, I checked the overflow bottle, and it was low. Filled it to cold level again, let it run some more. In the next hour or so my wife and I are going out to run some errands and to be 100% sure all is well.

When you use the bleeder screw, place a rag underneath it just in case you let a good amount of coolant out so it doesn't drip down onto the optispark, Always protect your optispark!

jon7190 wrote:

When you use the bleeder screw, place a rag underneath it just in case you let a good amount of coolant out so it doesn't drip down onto the optispark, Always protect your optispark!

It's been mentioned before,.
The optispark is a watertight sealed unit.

I normally simply take the coolant cap off (next to the reservoir) and let it run, adding coolant as the air works its way out of the system. Works on a 305, not sure if it would overflow on a 350/LT1?