anybody use infrared thermometers to check car?

"George Orwell" > wrote in message
...
>I took my car to radiator service, and they had one of
> those infra-red remote thermometers with laser sights.
> So they could measure the temperature of the bottom
> radiator hose, transmission oil cooler and all sorts of
> stuff. I thought of getting one. It seems the good ones
> (with accuracy of 0.75 Celsius) are about $200.
> Any DIY car enthusiasts got one in their back shed?
>
I just picked up one of these units. I couldn't resist the sale at $19.
Lots of uses around the house at this time of the year in finding
air leaks, and checking out the cooling system on the old car.
Can anyone shed some light on the theory behind what makes
it work. I know that it measures the electromagnetic radiation coming
from the surface aimed at to determine the temperature. I don't
see how it works when the object surface is made of wood.
Any takers?