I bought a 2010 Forester in April. It had an airbag recall. While at the dealer getting that fixed, they informed me I needed a new head gasket. In August the gaskets were replaced along with all the seals that had to be removed. The radiator was replaced. I also had to put a new catalytic converter on it. The weather was still hot. The AC worked fine. Now it's cold outside and I've discovered the heat is only working on the driver side. On defrost, vent and floor the heat only works on one side. The passenger side stays cold. Also, the upper radiator hose gets hot while the lower radiator hose stays cold. Not sure if that is normal. The radiator is full of coolant. Any ideas?? All help is very much appreciated!