I noticed almost 3 months ago Bmw x5 that the engine temp barely ever made it to the first white mark on the blue gauge when is -12c to -30c . i took it to the mechanic they could not find the course , then i used diagnose tools , it was reading fault on lambda sensor , which i find out it was unplugged from the previous repair so i replug it , it was fault free. but yet the temp can barely make it to the blue in -12c to -25c even when i drive the car for 20 minutes, (what doesn't lambda sensor have to do with engine temp ?) I m really worry please help me, is really cold here in Greenland without this car i cant take my kids to school. thank for advance help