05-05-04, 04:12 AM
I need to drain my cooling system so that I can fill it with the proper 50/50 mix and add the sealant additive. I was wondering how many gallons does it take to fill the cooling system for a 97 DeVille with a 4.6 Liter Northstar engine.
My '98 Seville (same engine) capacity is 12.5 quarts. Never have measured how much of that 12.5 will drain out when a hose is pulled.
05-05-04, 09:27 AM
The book says 12.5 quarts (3 gallon), but I've never been able to get it completely drained. After draining from the radiator, I can only get 2 gallons in before it is full.
The service manual recommends that you flush with water until the drain runs clear. Presumably that means there is no coolant left in the system, just water. Then add 6 quarts of straight anti-freeze and finish filling with just water.
I got about 10 qt out by blowing air into the system for my 98 Devill. I added 50/50 premixed.