2004 Concorde 3.2 lt LXi

Car is overheating (temperature gauge in red) even though antifreeze
is full and not bubling when I stop and open hood. Could it be the
thermostat?

 

yes it could and so could debris in between the condensor coil and
raditor restricting airflow thru both so could a cooling fan not turning

 

I would definitely check for proper fan operation. They do wear out.
Check fan fuses, realizing that if any are blown, that is usually due to
a bad fan motor.

Check thermostat too if the fans are operating properly.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')