Something I never really thought too much about was how long you can leave the block heater plugged in? Overnight? Several days straight? Whats the general concensus about it? Amount of electricity used not an issue.

 

The heater is about 1000 watts, so it heats up things pretty quickly.
I plug it in for an hour or so before I need the truck.

If you plug it in overnight and it snows, it will melt most of the snow off the hood it puts out so much heat.

 

Some googling suggests the stocker is 750W, but there are higher output direct replacements. If you really needed to know you could use an amp-clamp or check resistance and do math.

Check your cord condition.

I agree that overnight is fine, but I prefer 1-2 hours before I driving. If it were colder here more often I'd use a timer.

 

I don't really know whether or not my 2009 has a block heater...I may wish I had known this Friday morning when overnight low temps are predicted to be 9°......Ben

 

I see no reason to leave it plugged in for several days - unless you will be gone and need it warm as soon as you get back and it's freaklin cold out. Everything has a life span so no sense in using it up if not necessary.

Sometimes I'll leave it plugged in overnight (depending on the temps) but usually just try to let it warm for a couple hours. My rational is a block heater is cheap compared to a B3 Cummins. Having the first few seconds/minutes of oil flowing at correct consistency will help extend my engine's life (plus warm the cabin sooner). I may not get the benefit of that longevity, but the next person might!