Heater control valve blowing out?

On my wife's 740T, the thermostat got stuck closed, and she drove the car until she saw steam. The steam resulted from the heater control valve literally blowing out and becoming detached from the hoses. She said the temp guage was "off the scale, to the right".

Fortunately, the car had the waterless Evans coolant in the cooling system. The cylinder head and headgasket stayed put - no warpage or any damage. After installing a new thermostat, heater control valve, and new coolant, everything is now back to normal.

Has anyone here experienced a heater control valve exploding out of the cooling system? If so, what other damage was caused by this?

Thanks in advance,
Keith.

This happened on my car once. i was taking off from a stop one night at wot when at about 5k in 2nd. i herd a loud boom under the hood. quickly jumped off the gas and costed to the next light. no steam came out from under the hood. Since it was dark and i was only about a mile from home i drove it home and then checked out what happened. The valve it self broke into two pieces. I just replaced it w/ some copper hose. no problems anymore. the old valve is still under my hood i need to get something to plug the vac line off that goes to it ( does anyone know where exactly it goes to?) I would imagen at the heater controls

Just replaced the Volvo (plastic) heater control valve on my '89 740 Turbo with an aftermarket unit from FCPGroton.com.

This one is metal, both the actuator and the vacuum servo.