The present invention a portable universal electric radiator cap pressure tester, having a multiple of common radiator cap filler necks fixed on a dash board. The fixed filler necks simulate the filler neck openings on a vehicle's radiator or overflow reservoir. This allows the user the ability to quickly install a common radiator cap on the face of the tool and pressurize the radiator cap to its maximum recommended pressure. This gives the user the knowledge if a used radiator cap will hold its recommend pressure and provide a water tight seal during operation on a vehicle when the engine cooling system is under operating pressure.