coolant block plug
 

After flushing the coolant, I went to put the block plug back in and it never gets tight. I did not want to keep going fearing it would end up inside the block. If you look at the picture, the plug is way below the threads and it still leaks. I don't know if this is normal as I do not have another truck to look at. I'm just afraid if I try to tighten, it will fall inside the block.

BTW, when I took the plug out it was not tight at all, but it did not leak. This is the first time the plug has been taken out.
https://cimg2.ibsrv.net/gimg/www.for...d38aaaf3c3.jpg

Just Flush to the face is enough. You may wish to use some thread sealer on the last installation.

So these plugs don't really tighten? I did use some thread sealant but it still leaks a little.
The passenger side block plug tightened and I did not use any sealant. So far there are no leaks from that plug.

Find another plug

I agree. That's a pipe thread. It's tapered, and it shouldn't go in that far.

I just used thread tape on mine and have had no problems so far (20k miles), I'd be getting a new plug.

Teflon tape [thread tape] has been the most reliable for sealing pipe threads for me,agree try another pipe plug,not all are cut to the same specs,you don't want to tighten to tight I used a 1/4 drive ratchet.

Thanks for all of the replies. I will get a new plug and put teflon tape on to be sure.

does anyone know the part number for the plug? Ford parts does not know and I can't find the number on the net?

It should be a standard pipe plug size. Something tells me they're 3/8 NPT, but I'll try to remember to take a look tomorrow and see if I can figure out what size they are for sure.

I would say just go to the hardware store and buy three plugs a 1/4" a 3/8" and 1/2" npt and take back the one's you don't use there isn't anything special about the plug besides the fact that it has a recessed square drive. You may be able to find one that has a recessed allen head but you may end up with a square drive outie.

What some of us have done is to install a ball valve and then a plug gently screwed into the ball valve in that location-it helps to drain the block more easily for maintenance work.