Repeated coolant leaks, first at thermostat at the completely idiotic PLASTIC thermostat housing... One of Fords better ideas? Plastic housing attached to a flush aluminum head with a "rubber-band" type O-ring? There's only about 1/16th of an inch of sealing surface and about the same compression distance? What were they thinking?

Housing leaks even when not cracked or broken, and breaks or cracks happen easily and will allow it to leak even more.

Thermostat housing cover, again made of PLASTIC is attached with 3 torx head screws. Not machine screws mind you, more like wood screws that bite into plastic only, not metal inserts. What a messed up design. No clear shot at the torx head screws which are by design a straight in design. They left 1/4 of the thermostat housing cover unsecured with no screw to keep pressure on the cover and then depend on a compressed O-ring to seal against the cover?

I've had repeated leaks block to housing, resorted to RTV to end those. Have had a leak at the cover that ends up needing a new O-ring at least once a year.

Have replaced the Torx screws with hex heads so that service isn't as frustrating. But screwing into plastic repeatedly isn't a good idea as at some point it yields and strips.

I'd like to have a metal thermostat housing and a gasket thank you Ford designers...