E39 doesn't like the cold
New to E39's, my wife had an awesome e34 that was used to cushion two SUV's. Shortly thereafter the insurance co. decided it wasn't worth fixing. Anyway, we ended up finding and buying a beautiful 2001 525i that looked and ran great. The only problem it had and we knew was a stuck open tstat. Living in FL. we weren't too concerned as it seemed fine and I figured I would correct at some point in the future.
Fast forward a couple weeks and we are having some cold weather,(for us) and suddenly the e39 isn't happy at all. Can't run it on the interstate as it drops the operating temp down in to the blue zone. So we figured until I get it fixed we'd just use for local driving but now with it being colder the car stalls right out. Only way to keep it running is to hold the throttle at about 1000rpm's until it warms up a little and then it runs fine.
Does this sound like just a tstat problem or maybe a VANOS issue as well? Doesn't have all the VANOS symptoms I have seen but I am concerned it is more than the tstat. Any help would be appreciated.
E39 2001 525i
E36 1998 323is
E34 1990 525i (deceased)