Just purchased a 08 F250 King Ranch with the 6.4. What is the proper start up procedure for a diesel engine when the engine is cold. Should it be allowed to warm up before driving?

 

turn it to the on position, you should see the icon that indicates the glow plugs have come on, give it a second or two and then start the truck. 1-2 mins is all that is required. In extremely cold weather maybe a pinch longer, like enough to go scrap the windshield.

Then just drive slowly a couple miles, that is the best way. Extended idleing is not good with the emissions stuff on these trucks.

 

This is from the owners manual (page 12 of the diesel supplement):

1. Turn the key to ON without turning the key to START. Do not start
the engine until the glow-plug pre-heat indicator turns off.
2. When the glow plug pre-heat
indicator turns off, turn the key to
START, then release the key as soon
as the engine starts. The glow plugs
will continue to be activated for two minutes after the glow plug pre-heat
indicator has turned off. If the engine is not started before the
glow plug activation time ends, the glow plugs will need to be reset by
turning the key to OFF.
3. After the engine starts, allow it to idle for about 15 seconds. Do not
increase engine speed until the oil pressure gauge indicates normal
pressure.

Page 11 also talks about a cold weather strategy:

Your vehicle may be equipped with a cold weather starting strategy that
prevents severe engine damage by assisting in engine lubrication
warm-up. In extremely cold ambient temperatures, this strategy activates
and prevents the accelerator pedal from being used for 30 seconds after
starting the vehicle. By not allowing the accelerator pedal to be used, the
engine oil is allowed to properly lubricate the bearings preventing engine
damage due to lack of proper lubrication. After the 30 second warm-up
period, the accelerator pedal will be operational again as long as the
pedal is not being pressed when the 30 second time limit expires. When
starting the engine in extremely cold temperatures (-15°F [–26°C]), it is
recommended to allow the engine to idle for several minutes before
driving the vehicle.

As Senix said, no need to idle them excessively....

 

As stated above this is correct procedure, just drive nice and easy for a few miles to let things warmup properly.

 

I will add one thing I read from the "What's New" PDF I found. Starting on the Job 2 trucks, there is a "Easy Start" function of the ignition. With this, you just turn the key until the ignition begins, then you can let go of the key. The starter will continue to crank until the engine starts. (In other words, you don't have to hold the key in "Start" position.) This was added to all engines (6.4, 6.8, and 5.4). Pretty cool, but not a life event type of thing.