I have a 2003 ford tarus, It intermitatly boils water out the resavor. the temp gauge does not show hot. have changed the thermostste, the resavor cap, flushed it out. what else could it be. it sometimes will go sevral days fine the all of a sudden there she blows.

the first thing to check is to feel if the radiator is hot, if the radiator feels hot and the engine is also hot the coolant is circulating ok then the problem is more than likely electrical, the temp gauge gets its signal from the engine control module the coolant temp sensor sends coolant temp signal to engine control module for engine managment purposes then passes it to instument pack/gauge, if the sensor was at fault you would have engine running problems also,with poss fault codes logged, if the engine and rad are cold/only warm after the engine has been run for 15 mins or so it sounds like the thermostat is stuck open but you have changed that. i have had faulty new ones in the past and have had to test them in a pan of boiling water, hope this is some help to you.

Many possibilities, first check water/coolant level, check for leaks after running engine for about 10 mins, or sitting overnight, then check radiator air flow is not restricted, and fins are in reasonable order, check fan, make sure it cuts in before engine gets to hot, check if there is water in the oil (looks creamy) or oil in the water, if so you need a head gasket and/or a new head. flush engine block with high pressure water in reverse flow direction, then check thermostat, use thermometer, put in a pot of water temp, is stamped on body of thermostat, if not, bring to boil, should open well before boiling point, replace if needed, check water pump fins are not worn away. get specialist to use lazer temp gauge.

Hope this helps.

Check the radiator cap, they wear out. Make sure that the coolant is the right mixture, Check the water pump.

it could very well be a bad gauge. when it shows the engine to be overheated or at the least very hot, check the actual temp at the water outlet where the upper radiator hose attaches to the engine. use a non contact thermometer to check the temp so as not to get burned in the process. if the thermometer reads way different than the gauge, the gauge is bad.

From what i know of these trucks, its a "common problem". There is a tsb on this and the gauges arent really accurate. The tow light is blinking due to heating(not really), its trying to tell you to stop towing. Ive read that some guys gauge is reading 250 which if it really were, the truck would be running. Water boils at 220(im sure u know that). Suggestions ive come across is adding aftermarket gauges that give "accurate" readings unlike factory ones that are controlled by computer. Aftermarket will give you independent readouts.Heres a temp check you can try on your truck, im not sure if it will work for your model.




This is for the regular dash, like in XLT.
key off
push trip button in and hold
turn key on
"test" will appear in message display. Release button.
Gauges will sweep
then just push the button each time to scroll thru various modes.
Mostly junk info, but eventually you will come to temp, it is in Celcius so you have to convert to Farenheight(temp x 1.8 + 32)
Normal temp for mine at idle is 88, so 88x1.8=158.4,+ 32=190.4F
You can also view digital tach. All these modes are real time, and will remain on until you cycle the key on/off.

VOLTAGE REGULATER IS BUILT INTO ALTERNATOR SO CHANGE THE ALTERNATOR.

Yes it sounds like you have a bad transmission temp sensor.

does the temperature gauge show the engine is hot?

Is your coolant actually boiling? Is so, you may need a new water pump.

Possibly, i would check the sending unit and of course the wires that connect to the temp prob. They often become worn or even short out on other wires. I suspect that the gage is telling the truth and you have a blown head gasket. Check the oil for water. Check the water level and see if you are losing water. good luck