89 80, what sensor is this?

[George Selby]

I've got the 89 80 4 cyl back on the road (thanks, Ben, trans appears to 
work fine, no funny noises!)  Anyway, I now need to get the car running a 
little better.  While replacing the trans, I noticed a sensor on the front 
of the engine was broken, and want to replace it, however I don't know what 
the darned thing is.  It is located to the left of the upper timing belt 
cover (facing the engine from the front of the car,) and screws into a 
metal bracket.  It has a temp in C printed on it, and has a single wire 
running to it.  Can anyone ID this sensor?

George Selby