the manual says it holds 4 gallons(16 quarts) ive drained the coolant...petcock on bottom of radiator...valve on engine under injector pump...and took heater hoses off and let hang below engine...but I only get about 10 quarts out... ive refilled with distilled water a few times to clean...ran and waited to cool...drained and still only get 10 qts… if I put in the PG Pre-mix, i'm afraid the 6 qts that didn't come out will dilute it further... any thoughts on getting all the coolant out...??? should I get a gallon of Sierra full strength, and put it in, then add the Bobcat pre-mix?