2001 f150 screw. 233,000kms. When the winter temps get below o c (Canadian) my truck starts rough and I can't get heat inside the truck. The engine temp gauge does not move much either. No problems in warm weather. Had it checked last winter, replaced battery, starter and alternator, said they changed sensors, not experienced enough to know. Any suggestions! I commute 45 minutes each way and it gets real cold inside the truck. Minus -30C tomorrow

 

for now I would cut a piece of cardboard and put it in front of the radiator. Sounds like you need a new thermostat.

 

need a new thermostat for starters, possibly need a new heater core too