Mathman to the rescue! (archive)

ASSUMING:
-Your cooling system holds 12 quarts.
-It was 1/2 gallon low.
-It was at 50/50 concentration before you added 1/2 gallon of pure antifreeze.
-It is now full (i.e. 12 quarts)
-You want to restore the 50/50 proportion by removing some amount of the current mixture and adding that amount of water.

HERE'S WHAT YOU DO:
1. Drain 1 quart 23 oz. of your mixture and dispose of properly.
2. Add 1 quart 23 oz. of water.

HERE'S WHY:
-You have 1.75 gallons of antifreeze in your system.
-You want there to be only 1.5 gallons of antifreeze in your system.
-Therefore, you want to drain 0.25 gallons of pure antifreeze, i.e. 1 quart.
-You have 1.25 gallons of water in your system.
-For every quart of antifreeze in your system, there is 1.25/1.75= 5/7 quarts of water.
-Therefore 1 5/7 quarts of mixture contains 1 quart antifreeze and 5/7 quarts water.
-Finally, 5/7 quarts water = 32*5/7 oz = 22 6/7 oz., approx. 23 oz. water, so the grand total is 1 quart 23 oz.

If all else fails, you still have enough coolant to do it right.
-Drain the system completely (& dispose of properly). For real this time.
-Fill your half empty container with water, making one gallon of 50/50 solution.
-Pour it in.
-Dump 1/2 of the other container into the now empty first container.
-Fill up both containers with water, so you now have two more gallons of 50/50.
-Fill up your cooling system & bleed as needed.

Thanks to everyone that's been helping me so far with this radiator situation. Unfortunately, I'm ready to abort the "mission". Got the new hose, got the right antifreeze, found the bleeder screw, purchased the proper tools, dressed up in my weekend "dirty" clothes, but now I think I'm in over my head. Here's the current state of affairs:
When the radiator hose blew, I think/thought all the antifreeze leaked out of the cooling system. So I purchased 2 gallons from the dealer. The parts guy said I would need 1.5 gallons of anitifreeze to mix with the 1.5 gallons of water that I would also add if the system was bone dry (which I figured it was). So...I attached the new hose and filled the reservoir with the new coolant. I then loosened the bleeder screw and coolant is coming out but there is no air coming out. What I'm thinking is that the system was not empty to begin with and now I have added over half a gallon of antifreeze (straight) to the system and now the concentration is nowhere near the 50% point. Now I can't determine what concentration of coolant I have and how to get it to the proper dilution. I'm sure there is air in the system but only coolant is coming out (alot of coolant!). Do I just let it run out and maybe there will be some air at some point? Or does this mean that the system is full? Do I start my car and see what the temp gauge does? Do I abort till monday and get my car to the shop? Damn! Damn! I was really hoping to do this solo. Is there still hope?

Patrick
88 535i

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