The Most Economical Unit to evacuate, test and refill engine cooling systems. Tests for leaks-confirms system integrity, reduces chance of refilling a leaky system. Eliminates potential airlock problems-refill cooling system using "Patented" vacuum technology. Refills in seconds-quickly refill from new or used coolant reservoir. Accurately pre-mixes water and anti-freeze in convenient 3 gallon (11.3L) holding reservoir. Connects easily to most engine cooling systems.