Hello . This summer I purchased a 2009 ES model with 2.4 engine. It has 180,000 kms , and not much heat , so I replaced the thermostat with an 82 ° c . My problem is the gauge will go to the halfway mark , when it is around 0 ° out , but when the temperature drops lower the heat gauge does not maintain halfway , it goes to around 1/3 mark.
Did I get a bad thermostat? I would think the thermostat should maintain a constant temperature once the car warms up. So far it has only dropped to around -10 ° here in Canada so far , but cooler days are coming.

Any suggestions ?