Star nut on thermostat housing

[wrvond]

Still winterizing the 7.4L. I need to pull the thermostat housing and thermostat, but don't have any star sockets. I'll buy a set if I have to, but would prefer buying just what I need to do the job.
Anybody know what size I need?

 

[Fun Times]

What year is the engine? Carbureted or MPI?

Does the bolt look like the bolt linked below? If so it's a standard 3/8th - 12 point socket...Also if needed, Search 12 point socket online for an image to start with.
http://www.ebay.com/itm/Mercury-Mar...ash=item43f8778ef6:g:9gYAAOSwnFZXUNhc&vxp=mtr

 

[wrvond]

Sorry, I didn't realize carb or MPI made a difference. It is a 1995 carbureted 7.4L and the bolt you linked to looks exactly like it.
Thanks!

 

[Bondo]

Ayuh,.... The bolt in FT's link is a 12 point head, which takes a 12-pt socket, pretty common,....

I believe torx heads are 8-pt,...