1996 Jeep Cherokee adding temperature guage

If your probe is too small for the drain hole, go to your local parts or home improvement store and find a suitable adapter. Bring both the plug and the probe. Tell them that you need to install the probe into the drain hole. If for example your probe diameter is 5/16" and the drain plug is 1/2". They will find you a hollow adapter measuring 1/2" outside thread with 5/16 inside thread. Make sure you use Teflon tape on the threads prior to installation.

you didn't give any input on removing the plug. is there a special tool --- or can i just drill thru and use a large extractor?

I didn't think I needed to. It looks like an oil drain plug, I think you will need to use 19mm socket to remove. The hole is already threaded, that is why I told you to get an adapter for the probe. Unless if the probe is much larger that the hole itself, then you will need to drill and extract.

Sorry. The plug is round and threaded but has a recessed center --- more or less square ---- have to stick something into it to remove. 3/8 drive is too big --- that's why we tried a 5/16" piece of stainless keystock --- but can't get enough leverage to break it loose. I will try drilling it so I can get an extractor into it --- and remove it that way. No problem on getting the adaptors --- think I have what I need --- just going crazy on trying to get it out. Was not comfortable drilling because of possibility of getting shavings inside --- but guess it is just in the water jacket so should not create a problem. Thanks for your help ---

No prob. Good luck with the project.