Patent pending coupler combines pressure, vacuum, and temperature testing capabilities in one kit. Test cooling system with engine on or off to pinpoint leaks or diagnose blown head gaskets, cracked block, or damaged head(s). Refills cooling system in minutes without trapping air that can cause overheating. Components connect using self-locking quick-disconnects for easy and time saving assembly and breakdown. Includes four (4) adapters for connecting to the most common radiator and coolant bottle necks found on Domestic and Asian automobile's Performs pressure, vacuum and temperature diagnostics and refills cooling systems in minutes. The MV4525 is the most innovative, advanced automotive cooling system ever designed. It's the first and only tester developed specifically to run complete cooling system diagnostics with the engine running at normal operating temperature and pressure. New patent pending technology combines testing and monitoring of pressure, vacuum and temperature simultaneously, to provide real-time data far beyond the capabilities of a simple pressure test. This combination of features ensures the most extensive, accurate cooling system diagnosis possible. Engine ""On"" Testing - With the engine on, monitor temperature, pressure and vacuum simultaneously to quickly and accurately diagnose a blown head gasket, or cracked or damaged block or head. Also diagnose faulty components such as a thermostat, fan switch/relay, or cooling sensor. When testing is complete, use the built in valve to safely drain off pressure and hot fluid without having to wait for the engine to cool. Kit Includes: Pressure pump, Four (4) adapters for testing cooling systems on most Domestic and Asian vehicles, Compressed-air-operated Venturi Vacuum, Compound Pressure/Vacuum Gauge, Valve Coupler, Temperature prob, Hose clip, 5' coolant refill hose, (2x) 30"" Extension hose, Drain Hose, Adapter Wrench, Custom Molded Case, User's Manual.