As of right now I lack one of those digital heat meters, but I plan on picking one up soon.

So far I've been getting various opinions as to how to "measure" heat with using a drop of saliva on the cooling head and if the saliva sizzles off, its too hot. This evening, I was running my buggy with some friends in an empty parking lot and did the "saliva test" and the spit sizzled off the cooling head, is it too hot? or is this an inaccurate way to measure heat?

The person who tuned my engine used the digital temp meter and it measured at 190 degrees after several short sprints and said it was perfect. Yet even at 190 degrees the saliva still sizzles.

Also how do you know if your engine over heats? what are some of the symtoms? any long term effects?