The teflon tape would not be an issue in this case because he is getting a reading indicating the sensor has a ground, and it appears to be reading properly if he has a 160* thermostat.

If he had a blown head gasket he'd have coolant in the oil and vice versa - doesn't seem to be a problem.

And the use of a hose as opposed to plugs should not be an issue either unless he is overheating because he would be recirculating heated water directly back into the system.

Frankly, it sounds like, as Ross stated, it's just too full. You will get at least a pint of expansion from 60 to 160* Lower the level down to about the 2" previously recommended (or youcan just drive it and let it vent the excess to the right level), then go out and drive it. That will shake the bubbles loose (trapped air expandes significantly more than coolant - especially if it boils), it will heat up the oil to optemp, and push a proper cooling stream of air through the radiator.

Take the coolant jug with you on your drive and after 2-3 minutes after the thing getting to operating temp, CAREFULLY open the cap (let any pressure release first) and refill it to with in two inches of the top. If it's full or dumping coolant overboard, don't refill it and let it dump it. Drive it some more and when you get home check it again. If it's within 2 inches leave it. Then in a week of driving or so, check it again warmed up. It will expand and dump excess coolant, so when the engine is cold, it will appear to need coolant because as the coolant has cooled, shrunk and drawn air back in the radiator cap. Do not refill it. It should be OK.