Reb78

***********UPDATE*************** After many hours of troubleshooting this is what I found: the radiator cap had failed. I could hear a rattling noise that was coming from the passenger side. Couldn't pin point it until I did a pressure check on the cap. Replaced and the car started to heat up inside, but would still drop off when driving. The thermostat also had failed, even the new one that I had replaced failed. After installing a second thermostat the heat was there.... Although not as hot as it should be on the passenger side, but not blowing cold air anymore either. May look at doing the heater core again, but at this time in the middle of winter, I think I can live with the heat I now have.

There’s a class action law suit for these early year Journeys for core sand not being removed from the engine block correctly and plugging the coolant system especially heater cores.

Probably the heater core. Post a pic of your HVAC control unit.

That’s the only thing I can think of too. It started when I had a leak in the overflow tank. Replaced it, burped it... no change. Replaced heater core, burped it... little to no change...pulled both actuators, both work and no visible breaks. Closing the door manually still had cooler air on the passenger side. I’m at a loss... maybe have to try burping it again. as I’ve been reading these are notorious for trapped air.

The pic below are the only HVAC controls in the vehicle.Are there any other actuators besides the one on the driver side and the one on the passenger side for the mode select?

No heat on passenger side of my 2010 SXT. Checked the actuators they are working. Replaced the heater core, no change. Manually closed the blend door with the actuator removed, still no heat on the passenger side. Looking for suggestions.