I have a F350 Diesel. It is loaded. It has an Engine Block Heater.
I have no idea as to what it is, what it does and how does it work. When would you use the Engine Block Heater?
The truck also has a Rapid Heat Supplemental Heater. Again, I have no idea as to what it is, what it does and how do I work it.
Any info to this new truck owner would be appreciated.
Thanks

 

What year truck is it? Not that it matters really, I believe most ford block heaters work by heating the oil with a heating element, plugged into a 110V outlet, which in turn heats the block and oil to aid with combustion at cold startup. I am not familiar with Rapid Heat However.

 

If it's got the Rapid Heat, it has to be 2008 or newer. The Rapid Heat Supplemental Heater is pretty much what the name implies. It's a supplemental heater that warms the air coming into the cab through the heat / AC vents to speed up the warming process when it's cold outside. I don't recall the specifics of it but I think the information I read said that initially, it would blow about 20 degrees warmer than the cab temperature when you start up. Essentially, it's to heat the cab faster so you're not waiting on the coolant alone to come up to temperature to run the heater.

 

Very nice, and interesting, I wonder if it's using an electric heating element to do that, I know some of my old toyota 4runners with rear heat used electric heaters with fans.

 

Yes it's electric Alan. It operates when the engine coolant is below 85 degrees and when the HVAC controls are on. It's pretty handy. I've got it on my '11 and you can tell a difference as soon as you turn the heat on. It's not been that cold here lately but it does warm up pretty quickly. I'm interested to try it out this winter to see how it performs.

On the OP's truck, the engine block heater should be installed in the block and it warms the engine coolant.