I'd go buy a bottle of pre-mixed antifreeze, and just fill it up with that. Less hassle, works great.
You need 1 1/3 quarts of pure antifreeze.
The original solution has 3.6 quarts of antifreeze in it. The equation then becomes (3.6 + x)/(12 + x) = 0.40, where x is the amount of antifreeze added. X is then equal to 2.
If my math is correct it would take an additional ( .6 of a U.S. quart of antifreeze ) to increase a 30 % antifreeze volume to 40 % if the total volume of the mixture is 6 quarts
In the original solution, you have 5 quarts total, 20% antifreeze. So 20% * 5 = 1. You have 4 qt water and 1 qt antifreeze. You will add an amount A, to this mixture. When you add, the new total volume (in quarts) is 5 + A, and the percentage is:(1 + A)/(5 + A) x 100%. So when you start out at A = zero, you have 1/5 x 100% = 20%.So set up the equation (1 + A)/(5 + A) * 100 = 30, and solve for A.Multiply both sides by (5+A) and isolate the term A. Note that since you are adding, the value of A will never be negative (so you don't have to worry about the denominator (5+A) being zero.Answer = 5/7 (quarts) = 0.714285714285155 quarts.
4.2 quarts
4 quarts or one gallon of pure antifreeze, mixed with an equal amount of distilled water, for a 50/50 mix.
9.1 US quarts
For the 2003 Ford Ranger with a 3.0 liter V6 engine and AUTOMATIC transmission ( 7.4 quarts of antifreeze ) * That's for a 50 / 50 mix of 7.4 quarts of antifreeze and 7.4 quarts of preferably distilled water * because the engine cooling system capacity is 14.8 quarts according to the owners manual
For a 1987 Mercury Grand Marquis : For the 5.0 liter / 302 cubic inch V8 engine ( 7.5 quarts of antifreeze with 7.5 quarts of preferably distilled water should give you a 50 / 50 mix of engine coolant ) --------------------------------------------------------------------------- For the 5.8 liter / 351 cubic inch ( 8.0 quarts of antifreeze )
2 gallons of non-toxic antifreeze
13 quarts
2