Thanks for clarifying. I knew that, but I think I may have just read too much into it. I thought he meant the heater had a direct effect on MPG's vs. the indirect effect of the engine being warm and therefore more efficient.

 

most after market heaters hook up into the heater core hose (cut and patch in) and bolt up to the frame. get one with a t-stat built in other wise there is no control and it gets to hot

 

Winters here in Kamloops BC aren't as cold as they used to be - I am new here and didn't quite spend all of last winter -but we are on an elevated part of the city and it's therefore colder, I'm planning to use my block heater as the truck's a bit older, '92 and I'm not going to take any chances...

There are aftermarket accessories you can get that block heaters plug into, we have a whole range at Canadian Tire and other places, eg timers, thermostats - so they only kick in when it gets really cold etc. There are also magnetic block heaters that just clamp to the side of the motor, if you don't want to go making holes in it etc. Not sure how efficient those ones are. If it really gets cold where you're at, you could consider a battery heater too...

My big worry is forgetting to unplug the thing when I leave, which is why I'm planning to hang the extension cord over the driver's mirror when I hook up, so I don't forget.