Drivers side heat blows cold

The heater cores on these vehicles are like a radiator, tank on top and bottom, not like the standard ones were used to. they plug very easily. half of the core is the passenger side and the other half driver side, the passages farthest from the fittings get plugged, that side is the drivers side.....therefore no heat, the passenger side gets the flow and heat. Had to replace Heater core.....a major undertaking to say the least. must remove the Dash assy. and Heater box from vehicle !!

I changed my heater core and it blew hot for 1 day and then literally the day after that, the passenger saide blew only warm and the drivers side blew cold

I have a 2012 Jeep Liberty Latitude Sport. Had same problem with heat. Was told I had a small leak in the radiator. Replaced radiator, filled with coolant and ran engine and filled radiator until thermostat opened and topped off. Checked cabin.....same problem. While vehicle was running, it made some interesting sounds...like the fan was hitting something. There is a bleeder valve on an aluminum elbow next to the alternator going to the upper radiator hose. Opened bleeder valve (allen), unfortunately it blew out due to pressure (not super high pressure though), shut off car and let pressure release with valve nut removed. Replaced valve nut, began filling again after car cooled, and heat worked great. I read that these vehicles are prone to getting air pockets in system. Probably just loosening bleeder nut, and allowing all air to escape, even if it means removing plug entirely, and then starting coolant fill over again may fix uneven heating in cabin.