I just purchased a 67 Econoline van with a 170 6 cylinder and the temperature guage is inoperative. So I begin by looking for the temp sender to make sure it's connected. But I can not locate it anywhere on the head or the block! The engine is very clean so it can't be hiding under any mud or grease. I've looked from the top, bottom and all sides with no luck. I found the wire that's supposed to connect to it, but no sending unit. Could some kind soul help an old man out and tell me where the temp sender is located? Thanks!

 

On this drawing, 10884 is the temperature sender. It is just behind the last spark plug on the head.
The sender may have broken off, or someone might have removed it and inserted a 3/8"-18 plug to fill the hole.
The full part number is C6DZ 10884-B (Motorcraft # SW-552). This is for late 1966 through 1967. Earlier heads had a smaller hole in the head and need a different sender.

 

Thank you Emil for your help. I did locate what's left of the sending unit right where you said it should be. The top part of it is broken off cleanly making it appear to be a bolt threaded into the cylinder head. Thanks again for the info and the quick response to my post!