My 1997 camry has been regularly maintained and has about 200k. Lately the heater has not been getting as warm as as it used to and actually gets cooler at idle. temp gauge reads fine and thermostat is opening properly. Any ideas what the problem might be? Thanks Mike

 

might be the problem is on the heater, it heating up capabilities got reach the limit so it heat up fast...

 

Is this an auto or manual climate control system?

The heater core could be plugged or the heater control valve stuck closed.

Look at the engine side firewall, drivers side and find the two hoses going to the wall. One has the heater control valve installed. There is a arm with a push/pull wire attached that opens and closes the valve. Make sure the arm moves when you change climate temp and that the valve is open.

If Ok, the heater core could be plugged. Remove the two hoses, suggest where the attach to the engine. Removing the hoses where the heater core pipes exit the firewall is difficult and the pipes can be easily crushed if using tools to aid in removing the hoses.

Making sure the valve is open, run garden hose water through one hose and watch the other. When the water comes out clean and at full pressure the core is clean.