engine manifold leak on 2001 Ford Explorer

Is the manifold made of plastic. I have to keep adding coolant every hundred miles and was told it is not the thermostat but that the manifold is made of plastic and it becomes warped and a repair will cost over $1200.

Asked by for the 2001 Ford Explorer
Yes the manifolds are plastic manifold and they commonly leak. And $1200 is abut right, sorry to say. But get a second opinion on the leak, because they usually run poorly or set a Check Engine Light, I have not heard of many leaking coolant, so make SURE the manifold is the source of the coolant leak, have someone pressure check the system and then SHOW the place on the manifold where it is leaking.