well, is it mechanical or electrical? i assume you have a 4.6, 1996? i drilled and tapped a hole in the water neck, thermostat outlet thing. use lots of teflon too. it doesn't leak one bit on mine. i don't think this is the best place to put it, but it works quite well for me, and it gives the temp of the water coming out of the engine, not the water going into the engine.
