On 09/04/2018 15:32, Graeme wrote:

Any tips for removing a housing that has been in place for many (25+)
years?Â* This particular engine is in a 68 Traveller, and the stub for
attaching the top hose has disintegrated, which does not help the water
circulation or cooling.

YouTube videos on changing the stat seem to gloss over removal of the
housing, which seems to weld itself into place!

Very common problem, studs rust and make removal very difficult.

Screwdriver between housing and head and hammer in. The cast iron head
won't usually be damaged as its so hard. The thermostat housing is
toast. It should eventually work itself off with levering from different
directions.

Get a new thermostat housing and possibly some new studs. I'm not sure
but think one stud goes into the water jacket. eBay should be a good source.

I had to drill one stud and retap to clear fragments, I can't recall the
thread! Probably 5/16 UNC

Good luck.