You don't already HAVE a block heater installed? The original books contained a coupon for a free block heater to be installed at the next servicing.

I never use a block heater up here in the northeast. I simply let the car glow two times(full 60 secs), crank it over for max of 30 seconds until it starts to fire(all the while my right foot is half-way on the accelerator).

My 350 seems to start at any temp....At least that was last year, prior to my oil consumption problems and reluctance to start often as of late(hmmm...,).

My 300 would start without a block heater down to single digits. Then, you were challenged. I mean, if you have a battery charger, then you're all set. If not, the challenge becomes trying to overcome a severly fatigued charge on the battery while cranking your diesel over in the cold.

Add some Power Service Antigel to the tank. It should help. I never learned about the PS products until after last winter. Great stuff, and improves the quality of lousy fuel slightly, as well.

Good luck, and make sure the underbody has plenty of coating left to it. Keep it clean.