I bought a Digital Infrared Pyrometers from a local parts store for $40-$50.
Here is a link to Summit, they have several
http://store.summitracing.com/egnsea...115+4294854731
I use mine to check the temperature at the sensor to prove the gauge is correct. I also check different point of the engine, hoses and radiator. You can check header temp. I use mine to set the adjustable fan switch. It's a handy tool.
Dwight