Ford Repair: 4.6 triton overheating, blown head gasket, head gasket problem

Question
Hello.My 1997 f-150 61,000 mile 4.6l triton seems to have a cooling problem.In the cool mornings I start the engine and let it warm up.One morning the heater did not put out heat so I popped the hood and noticed a rusty/yellow water spray pattern on the engine compartment.Aparantly the coolant was spraying from the cap on the reservoir.Also while driving the truck the temp gauge will jump from cold to extream hot and the oil light comes on,then in an instant the needle will go back to the center of the gauge and I will get heat-and the oil light goes out.I pull off the road and notice fluid spray again.I can tell you the top hose is swelled and cool and the one heater hose is HOT as h@#.The fluid in the reservoir steadaly rises until it blows fluid then the heat works again.A mechanic buddy said there might be air in the system or a blown head gasket.The check engine light has been one for some time now   I have tryed flushing the old coolant (using prestones flushing kit and a garden hose) and a new-tested in boiling water- thermostat.The problem has not changed.It seems to be fine at start up but quickly builds pressure about 5-10 min. and blows fluid out the cap.I can only guess that the fluid is blocked somewhere.Please help.Any info would be great.Thanks...Mike

Answer
i definitley believe you have a head gasket problem-if the mileage is correct and you have rusty water your head gasket has probably been eaten through somewhere because rusty water becomes acidic and slowly eats away at gaskets all the symptoms point to it also-