I have an adapter for my oil temp gauge and its a m12x1.75, but I'm wondering if it will fit in the drain plug spot because I think the thread on the original drain plug is m12x1.75x25? correct me if I'm wrong but it would make my gauge install a lot easier if it would fit.

 

Will it fit? Yes.

Should you use that? No. Its most likely an NPT to that thread and i bet you will kink or damage it taking it in and out so much. Pop your intake manifold and replace one of your galley plugs (allen head) on the front of your block.

 

Would I use Teflon after the first three or four threads so that I don't get any in the oil? or will it just stay where it's supposed to and I don't have to worry about it getting in the oil.

 

yes. Teflon tape it so it doesn't leak.