Why is my 99 Taurus se building pressure in the coolant reservoir?
You may only see obvious coolant in your oil pan after considerable water has made its way into combustion chambers. For a small crack in the head, or a tiny leak in a head gasket, excessive pressurization of the cooling system by exhaust gas is a far more common first symptom. You can test this with an inexpensive radiator cap pressure guage: http://www.sears.com/shc/s/p_10153_12605… The normal expansion of coolant with temperature will naturally pressurize a cooling system to a few pounds per square inch range. But exhaust gas leaking into the cooling system will quickly drive that pressure 2 or 3 times higher, often blowing out the coolant past the pressure relief of the radiator cap, and perhaps damaging other parts like hoses and coolant reservoir.
