fossil

Why not just leave the block heater cord the way it was intended. Put on an oil pan heater pad and tie it into the system. Now when you're plugged in your engine oil will be nice and warm and when it gets really cold your block heater will kick in and you wont set off any codes. One thing with a block heater is that the block stays warm but when it gets really cold the oil in the oil pan stays thick as the heat doesnt make it to the pan.

You can install a pad type 75W oil pan heater which will also keep the oil nice and warm when it gets below 0.