I installed my twin SPAL fans today and the instructions say that you should not put any teflon tape on the sensor but I can't get it to stop leaking. It is mounted in the head. Should I try the teflon tape anyway? Anyone ever had this problem?

I never use the teflon tape but I pretty much always use some type of 100% silicone sealer. Just a little in the threads, I think that the lubricating properties of the silicone do just as much if not more than the sealer effect, then the fitting goes in that little bit farther.

tighten it farther. unless it's a 2 wire sender, it needs full electrical contact with the head to complete the circuit to ground the relay when it reaches a certain temp.

it is the one wire sender and its as far as I can get it in but still leaking. Is that a no on tape or silicon sealer? any help will be appreciated. I'm about to go lift the hood and start trying to fix it. Any idea of a replacement part number from Advance or AZ? if I can't get it to stop

I had the same problem, just put tape on the upper threads, and leave some on the bottom exposed. You can then put a meter of the base of the sender and your head/manifold to see if there is continuity between the two. Worked fine for me.

I installed my twin SPAL fans today and the instructions say that you should not put any teflon tape on the sensor but I can't get it to stop leaking. It is mounted in the head. Should I try the teflon tape anyway? Anyone ever had this problem?

lock tight sealant in the last 4 threads .
as Onick stated then ..You can then put a meter of the base of the sender and your head/manifold to see if there is continuity between the two. when it reaches temps 195 .. it's a ground switch at that point .. run another wire to the top of the sensor to a toggle to ground so you can cycle the fans at will with the key in the on as a over rid to temp on only .
Don