1999 Mercedes-Benz E-Class "heat pump kicks hums" Questions

...rather than -20 deg. F freezing windshield wiper fluid. Try to warm up the car by parking it in a heated garage until the windshield wiper fluid thaws. Then, try to use it all up, and add the ...

loud engine noise and over heating. loud humming in engine while getting up to higher speeds for past 2 months, and now over heating, but not registering. I changed radiator cap, but water still boils