91 spirit gauge say overheating

[lostincanada]

hello. I have a 91 dodge spirit with approx 400,000 KM on it. The head gasket blew in november, so I change it. It was fine for about a month, but now the gauge says it is running at about 220 degrees. I have change the coolant sensor, gauage sensor, gauge. I have installed an after market guage and it also reads high. I have tried a rad and hoses, same result. The water pump is about 1 year old. I took it to a mechanic this week and he was as stumped as me. I sugested to him tahat maybe it needs a flush, but he did not agree. According to the scan tool he put on it the computer says it is running at normal temp. I have tried a 192 and a 180 thermastat with the same result. I took the plugs out and none are whitish. I sure hope someone can help me. Been a great car for me. Hate to see it go.

[macncheese]

ummm air bubble maybe? a flush never hurt a radiator, either though. i like the prestone flush kit. it's basically a tee that fits into your heater hose, and screws into a garden hose. so you hook up the hose, run your car to warmup, then the hose flushes the entire cooling system and it all washes out the top of the radiator. costs about $3 at autozone.
good luck
tony

[FallenFast1]

Air bubbles,yeah, drill a small 1/16 hole on the inner rim of your thermostat so the engine will bleed itself. Air in there is extra bad. Make sure the hole is on top when reinstalling(12 o'clock)

[pcv]

If the temperature according to the scan tool reading was normal, then you have a problem with the temperature sending unit and/or the gauge itself.

[jasonj]

air bubble at temp sender.factory dodge thermostat has a small hole in it,but i've found the best way to get the air out is to take the easiest of the two heater core hose off,then fill with antifreeze.