Hi, hope the New Years treats you right! When I bought my 57-3100 the seller said the heat did not work. I'm not sure what he meant because it does work well,the fan is strong and the air is hot, one problem is that when it first comes on it fills the cab with white smoke for a minute or two then seems to clear up. It doesn't appear to be leaking inside the cab or along the firewall, so I thought it was the heating coil blowing off sediment or maybe there was antifreeze on the outside of unit and the fan picks it up. one final piece of information, when I bought the truck the seller has connected the heating hoses to themselves by passing the heater entirely. Could I use a radiator cleaning product to remove old scale if that is what it is? Any thoughts?

Thanks, keep truckin!