my car is overheating and i dont have aleak and coolant is full

flush the system real good and change thermostat. thats the cheapest way to rule out a clog or thermostat sticking. bout 10 bucks.

may be air trapped in the coolant system, had that problem. for me flushing and bleeding it worked. I left the coolant cap off topped it to the cold line, started the engine waited untill thermostat opened and drawn in the coolant and topped off as it took it in. threw the cap back on turned it off. and test drive it watch the needle closely for overheating or not at all. park let it cool top it off again, should do it.

Have the exhaust system checked for a restriction. This can be checked with a vacuum guage. I've had a similar problem with a catalyst converter being restricted on my vehicle.

I have a 2005 Mercury Grand Marquis smells like the catalytic converter is clogged and it also seem 2 Tremble When I mash the accelerator and then my gauge to act funny as well goin cold and hot I have a weird burn exhaust smell nd in reverse the exhaust treble nd da motor it not properly breathing so all honesty it's best to get da direct fit full system h pipe all v8 deserve one it increases horsepower and it anotherthing dnt neglect ya exhaust it cause thermostat nd radiator failure nd that y ya coolant drain tryna cool it down from da heat build up repair front cats and go h pipe straight pipe ne call Ford for ya upper steering shaft recall give ya vin num nd see if ya car need to get properly fix before it completely detach it self from in the steering wheel year 05 and yu basically the new box shape steering wheels

I've changed the radiator, water pump, and thermostat on my 1998 Mercury grand Marquis and the gauge still going up telling me the car hot

Try changing the coolant temperature sensor

I have a 96 grand marquis overheating i changed the intake manifold and the thermostat but its still keep running hot what am i to do

Flush the coolant system and the heater core