Someone suggested a preventative measure a while back; use a spray bottle to spritz a little antifreeze into the door cavity (through the plastic plug near the door handle) helps keep things from freezing up. I haven't tried it myself, but the people who did & responded in that thread seemed to be having some success with it.

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2001 X5 Sport 3.0/5-speed
1998 318ti/5-speed
1988 735i/5-speed
1984 528e/5-speed (soon to be M20B25-powered 525i!)