That is for certain -but curiosity has gotten the best of me...I just want to know how this thing works. It looks like it has a venturi in it, but that seems odd to me for an instrument designed for a noncompressible fluid. Looking into it -I don't see any kind of moving parts. Plus I am an R&D guy for a mechanical / hydraulic / pneumatics company and this might come in useful for something else...I am always looking to learn!
My Rad. would blow long before that...I have seen it when a friend was blowing up used heater cores trying to "test" them.