C water temp guage?

I'v got this thing on the C, I think i remember some people saying that it could be a water temp guage, but could it be an engine heater? it takes place of a head bolt... http://s24.photobucket.com/albums/c47/j ... rmall%20C/ I'm just wondering what it is, ifn anybody could help i'd appreciate it also wondering, what is the best way, if any way to clean out the water jackets and oil galley's in the block? their really nasty, I was thinking just put some engine foam in there, then rinse it out, but freezing temps kinda is holding that idea back

Thanks

Johnny

just looking at it more today... it looks like it actually goes into the oil, it has some writing on the top of it, but I can't quite read it, could it be an oil heater instead of antifreeze?

Johnny

Its a coolant heater, im pretty

Andrew

That is a head bolt engine heater. It goes down into the water jacket and heats the coolant for quicker and easier starting in cold temperatures. I think I would get rid of it. Replace it with a head stud.