I am way up north about 30 miles from the Canadian border. Clearing snow in the winter is one of the primary tasks for my diesel tractor (JD 4120 that I bought new in 2005). A block heater was the only option I added to it at purchase. I wouldn’t dream of starting a diesel engine on any machine up here in winter regularly without a block heater.
How long I energize it depends on the outside temperature. 1/2 hour is good between 25 and 55 deg F. If it’s colder than that, I’ll let it go for an hour.
I keep the tractor under a porch on the barn that I can see from the house. The block heater is plugged into a heavy gauge extension cord, which is plugged into an outlet that is switched inside my house.
There is also a light on the front of a boat bar in the house that is plugged into that outlet. I know the block heater is on when that light is on.
If it snows overnight, I’ll flip that switch as soon as I wake up in the morning. If it snows while I’m at work 30 minutes away, I’ll call the wife or kids and have them flip it when I start my drive home.
If you’ve ever had the chance to listen to a diesel engine start in cold weather with and without a block heater, you’d quickly gain an appreciation for the damage that is done to the engine by not using it. Mine sounds just like it does in the middle of July, in the middle of January, when I use the block heater.
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