1996 century no heat and loosing coolant.

My moms century just started loosing coolant recently.
The temp gague will go almost to the red marks.. meaning too hot.
the temp dummy light comes on.. its overheating.
I try to turn on the heater to dissipate the heat and it just blows out cold air and doesnt help at all.
It seems like the thermostat isnt opening but where is all my coolant going?
I havent looked too hard, but there doesnt seem to be any coolant in the engine compartment.
Where is the thermostat on this car?
Any suggestions on what to check and the general location.

Thanks in advance for any help.

It would help a lot if you would tell us what size engine you have! Generally you can locate the thermostat by following the top radiator hose back to where it connects to the engine. As for where the coolant is going it is possible that you have a leaking heater core that will push the water out a drain on the firewall and you would not see anything in the engine compartment or it is going into the crank case! Check the oil immediately!

i believe the engine is a 3.1

The thermostat is located on the driver's side right in front. Remove the two bolts and lift the housing off and then pull the thermostat out. You will probably need to drain some of the coolant to get the thermostat out. When you replace the coolant make sure you get all the air out of the system.