This is pretty typical of what is available. Pretty good price on this one by the way. I don't remember the brand we have (at work) but they were around $100. It works best if the area that you are getting the temperature reading from is painted black. You can take these and shoot all over/around the radiator, thermostat housing, hoses, etc... and get a pretty good idea of what the cooling system is doing.
temp gun
This one was the first one that came up on a search page. The ones with the laser pointer are easier to use. We use them for troubleshooting heat exchangers and to find hot spots on rotating equipment.