8 degrees where the '07 truck sat in the driveway this morning, plugged in on a timer two hours prior to departure. Wait to start light did not even come on. Outstanding!

In order to save electricity, I'm going to set the timer back a little to try and get a better idea how much plug in time it really needs.

 

I plug mine in at 20 and leave it in all night. When I go to start it the light comes on just like normal. I don't think the temp of the coolant has anything to do with the "wait" light.

 

In most climates, 3 hours is all you need. Plugging in all night is not needed and really is a waste of power.

If you think a block heater works slick - you should try an Espar or Webasto water heater. Its a diesel fired blaock heater that heats your coolant and circulates it through the block and the lines to your heater core. Trucks is warm when you get in, no more engine wearing cold starts, and you never have to scrape windows again!!

 

I know there's several even better options for cold weather aids out there like you mention Dr. I was just amazed at how well the stock block heater seems to work. This is only the second winter I've had the truck, and didn't use the block heater much or pay much attention to it last year when I did.

It must accomplish some small amount of circulation from just convection through the water jacket. That's the only way it could get the manifold on the opposite side/top of the engine warm enough yesterday night to turn off the wait to start light.

That is definitely a huge waste of electricity. I think that heater draws something like 750 watts. I also don't think it's really called for at all until you get down into the single digits.

 

Due to the amount of heat delivered by a block heater it is only possible to raise the engine temperature 40° to 50° against surrounding temperature.

If you want an ice free warmed up cab and a warmed up engine up to operating temperatures I can recommend an engine heater. I have a Webasto with 5200watts or 17200BTU's. In an half hour the engine is at operating temperatures.
It consumes a quarter liter of Diesel per heating process.
A disadvantage should be mentioned too: you need a good battery or better a dual battery system, because it takes a couple of amps to operate that heater.

There are two versions available: air heater and coolant heater. The air heater is only for the cab.
The coolant heater is able to heat the engine and with the heater fan the cab can be heated too. If you only want to heat the engine you can switch off the fan and save a lot of current becausethe fan consumes the most energy (100 watts) the heater unit itselfs needs only 44 watts.
Best adavantage is you can take that heater, if you buy a new car. If you think 5200Watts aren't enough- there are more poweful units available with 9000watts or more.

I don't won't to miss that heater again. I hate to get in cars of my friends- ice cold like a fridge...


And yes the engine wait to start light depends directly on coolant and outside temperature.
Our trucks had to be pre glowed up to two minutes in Norway during winter before you were able to start them with success.