So I'm new here, just signed up! I have an X5, I love it but have recently had a few troubles. I live in Saskatchewan Canada where it can get to around -40 to -50 Celsius. Most recently the coldest has been -30. My X5 would not start at anything colder than -15 also it has become very sluggish at taking off from a complete stop. I tried everything to fix my problems from searching on here and google to even installing an oil pan heater and nothing would make it start. Today I changed my battery and problem solved! It starts, has no end of power, it is like a total different vehicle. I cannot believe the difference after months of frustration so if you are having issues start there!