I installed a 1/2" shut off valve before the monovalve, and so far it seems ok, I took it for a test drive, to make sure my temperature doesnt rise, and it seems to be holding at about 80, if sitting idle for over 20min, it rises to 90+, which is a bit of a concern, but does not go above it. I am at the point where I dont want to sink too much money into this car because I dont have the time to play with it all the time. Its my wife's car, and she drives over 30 minutes to work each way, so I will have to get her something more reliable, but it burns me that i changed the evaporator last year, and that was a two day job, and now a stupid valve, costs around $400. This whole valve is so poorly designed, a simple ball walve with an actuator would have been so much simpler and more reliable.