Before I could get around to replacing my glowplugs I used a trick to save starter wear and tear on the starter motor from the excessive cranking needed to get my 1009 going. Remove your air filter element then reinstall housing empty and clean.. use a paint stripping gun to blow hot air into the housing. Length of time...use your judgement. Have an assitant crank the motor and walla! She fired up up almost instantly saving alot of excessive cranking. Havent tried a hair dryer but would probabably work too...just might take longer
Hot air, warm cylinders, and hot fuel are the keys to a happy starting 6.2 or any older diesel... While living at almost 9,000Ft elev in CO I went through 3 freeze plug heaters, 2 starters, and 2 batteries in one winter.
I finally had to put a Kats tank heater (circulating coolant heater similar to a tractor) on the fenderwell, a battery heater, and an oilpan heater, all were wired to switchs on the dash and then out to a single plug on the fender. thus one extension cord plugged into the fender and then select the heater or heaters you wanted on..... I ran the cord via a timer that that activated the system at 4am and shut it off at 8am, then again at 4pm to 8pm as these were the times that I would be typically needing to start the truck ( I lived at work so it was a two foot commute 100yrds)
As for the glow plug system, it is antiquated to say the least, It works but not well. Ether is a killer but sometimes the nessecary devil. The GP system leaves out the one key part that is needed, hot air.... the GP heats just the pre ignition chamber but not the whole cylinder. thus as you start to crank the heat soon leaves the chamber and enters the cylinder and is gone out the exhaust. Once I turbo'd my 6.2 I had a bear of a time starting it in any temp under 40*F Thus it became an extension cord heat junkie. All my GPs were new, but they just werent doing the trick.
Through some pondering my buddys and I came up with an idea that never really became a reality but wouldnt take much work.
Find the grid heaters from a 6bt Cummins, they are about 3.5x3.5 square and graft them into the intake of the 6.2 either by aluminum welding a bracket directly to the intake or by mounting intube for the air ducting system. for you Turbo'd guys, the aluminim cross over tube fromt he turbo is a prime location, anywhere is fine, just so the grids wont melt whats around them.. Wire them to some 12 relays off your existing GP relay (its 12v too, as the 24v is resisted down to 12 for the GPs) this way the chamber gets heat, but your also feeding it hot air down the intake.
My Cummins fires at -15*F with no assistance from the ext cord, so these little heaters are very powerful. just make sure your batteries are 1000Cold Crank Amps @ 0*F or you will soon have not juice as the heaters pull 240amps per cycle.
