Dear Scotty:

2007 Buick Lacrosse, 110,000 km (60,000 miles).  Living in Toronto.  On cold winter days, minus 8 Celsius (17.5 Fahrenheit) or less, the car drives some 3-4 miles with everything normal, then the temperature gauge needle goes to 0 and both radiator fans switch on at full speed.  It remains like this no matter how many times I stop and restart the car, during the rest of the day.  The next morning, operation is normal, until the same distance is covered if still that cold.  A mechanic has replaced the thermostat and the coolant temperature sensor (mounted on engine), according to the fault codes, but no change.  Also, upon restarting once the fans are on like this, the engine will idle about 1,500 rpm for a minute or two.

Thanks in advance.

Rejean (a French name)