This is interesting, because when I was a kid in the 70's, my dad drove his 240z in all imaginable weather conditions. We lived in the Boston area, so he dealt with a cold winter every year, and I know for a fact he drove it home from work during the Blizzard of '78. Additionally, he routinely used to drive up to the mountains during ski season, and I don't recall him having the problem you mentioned. Best of luck getting your problem resolved, though. -JML