The one I have I use for A/C work, it has a steel probe that just needs to touch the tubes on a A/C system. I use foam insulation wrapped around the probe so it isn't effected by outside air.
For your truck, I bet you could wire tie them around hoses or tape them. My older gauge I had I used on my uncles Stanley Steamer to measure steam temp going into the engine, I had to use wire to tie the probe to the steam line, but all it had to do was touch the pipe to get a good reading.
The cheap infra-red no touch thermo guns work really good for checking temps also. I think you could cut some hose and split it down the middle and use it along with wire ties to seal the thermocouple end to the hose you want to measure. Some of the cooling fan controllers insert the thermocouple under the radiator hose between the outlet / inlet and the hose, I haven't seen one personally, but they may be a thinner wire type and not the probe type.
On my truck, I drilled a hole in the thermostat housing that wasn't being used, it was cast for hole but never drilled and tapped. After looking at the 250's head, I could see just how close to the chamber the probe was so it was no surprise it read hot.
Last edited by Joe H; 04/06/2026 12:03 PM.
