Last night the lady pulled into the driveway and steam was coming out the front end.
The source was the area around the top of the thermostat housing but I can't pinpoint how it was exiting. Hoses are intact. The housing doesn't seem damaged.
Could a failed thermostat cause over pressure and create a leak where the top hose attaches top the thermostat housing?

 

Yes overheating equals pressure and pressure can build and cause leaks
A clog / stuck thermostat equals overheating

 

x1 if it's stuck closed for sure it will overheat which then builds pressure and then leaks follow.

Fit an aftermarket temp gauge with an audible and visual alarm it'll be the best insurance you ever invest in. Cylinder head/gasket jobs cost big bucks whereas a cheap temp gauge costs less than $30 in total and 1 hour to fit it. No brainer really

 

I'm fairly certain a HG job is coming very soon. I think I have coolant loss out the back but have not confirmed. Just got the thermostat out and it is covered with crap. I'll try to post up a photo.
I'm fairly certain it was stuck closed and kept pressure between engine outlet and the thermostat, causing the pressure to release at the point where the therm housing meets the top hose.

 

You can see where I rubbed some of the gunk off with my fingertip. Pretty old and nasty.

 

Yuck
Are you running dexcool? That looks like dexmud

 

Was dex cool. I flushed and drained and flushed and drained all that **** out. Now it's walmart cheap coolant.
Holding 212 degrees with ac running. Confirmed ac fan activation around 210.
Hit 215 sitting at a light with ac on the entire time.
Certain it was thermostat failure.
Is there like an awesome thread on keeping discos cool somewhere?
Parked it seems to hold 212 with ac on.
I still think that is too hot.
Summer is coming, are these temps ok to you guys or should I take additional measures?

 

To high for my comfort, especially in Florida. do you do a lower temperature thermo? How many miles are on your radiator and fan clutch.?

 

many, but its simple.
get the system in good order. flush out the dex and go green. get a 180 td5 stat..
you are likely due for a new radiator, if your stat was that dexed up. but the 180 will help. rovers north has them

 

History is unknown. We've had this rig maybe 1.5 years.
It's 75 degrees outside.
I'm at idle, parked, ac still running, temp between 212 -215.