Its not the cold, just neglected maintenance...Will happen to most 4.4's from 180 to 240K...Unless the timing chain and guides get replaced, this is what will happen even under normal conditions! We see it here every day.
IMO not worth saving this motor. Even at low RPM you can still bend valves, so chances are you need a full head job. Not easy or cheap. If not done by the right mechanic, you can run into even MORE problems, seen it more than once.
