[Axle]

When you put in that aluminum heater core, did you use sealing foam around it to fill any gaps? It does not take much of a gap around the core to lose your heat. I failed to do that in a car I had, one side had a gap and as a result of that, pretty much luke warm barely able to defrost. Pulled it apart, put on the sealer strips where needed and promptly got roasted hot in the cabin.