The "vacuum" sound you describe reminds me of the sound that a starter makes when the starter motor runs, but the drive unit does not engage the flexplate/flywheel. It may be a problem with the solenoid, or the drive itself. In either case, replacing the starter would cure the problem. Without actually listening to it myself, that's the best I can do. You might have an assistant watch the cooling fan while it's making that sound. If I am correct, the fan will not rotate. -40C can affect a lot of things, lets try to diagnose one problem at a time.
