Plugging in truck

[Diesel JD]

We'll guess from his handle it's an 89. All 7.3s and PSD engines are OK with the block heater as far as I'm aware of however 83, 84 and some early 85 6.9s have a casting weakness around the block heater and the wisdom of the collective has been that this defect together with block heater use caused most of the cracked block issues on the earliest 6.9s. If you have a 6.9 and you aren't sure if it is older or newer you'd have to go by block serial # and there is a definite break point in 1985 where they fixed this casting defect. The "good" and "bad" serial numbers are listed on this site somewhere. I usually use mine only on the coldest nights and only for a few hours at most.

 

[MIDNIGHT RIDER]

The block-heater in my old 6.9 gave up the ghost early in it's life; no block issues, the heater just quit.

Instead of replacing it, I just left it where it was and installed the biggest KATS can-type heater that they make.

Instead of simply running a heater-hose through it, like I see so many do, I followed their instructions to the letter and drew the cold coolant off the bottom radiator drain-fitting, straight into the heater, which was the lowest part of the system, even with the bottom of the radiator, then up and over to dump back into the block at the lower heater-hose connection.

Plain old block-heaters are good; but, I must say that can heater outdid any block-heater I ever used.

After an hour or so, the portion of the windshield immediately above the defroster vents would already be thawed and I had heat as soon as I started the engine.



So far as the electric bill, no matter how much or how little I use, no matter how many "energy-saving" devices I use, no matter how careful or careless I am about it, they sock it to me anyhow and I see no difference in the dollar amounts of the bill.

If I drop off in average killowatt use, before the month is out, they switch out the meter and I am right back where I was.

 

[smolkin]

With my brand-new (in Feb) OEM block heater I only need 45min-1hr, down to 17F (as cold as it gets here). No GPs at the moment, so it's 26F right now and plugged in. I guess with an older casting, use it at your own risk, but it works for me.

 

[82F100SWB]

Below about 5F, my 6.9 was started before it was unplugged, and plugged in before it was shut off. In warmer climates 3 hours is probably plenty, but, it takes a good 6-7 hours in the temps I deal with for the block heater to get to maximum effectiveness, and the transmission is still like rowing a stick in molasses. Plug it in at shut down, and it's not like that in the morning. It is easier for the heater to maintain the temperature on a warm engine than it is for it to bring a cold one up to temp.
My 6.9 would always start down to about -15, but, it and you were much happier if it was plugged in.

The circulating pump style heaters that Midnight Rider speaks of are the cats ass, second only to a fuel fired one.
That said, my old 460 had a pair of 1000W core plug heaters in it, and I of course didn't pay to plug it in at work... Even at -30 at the end of a shift, the hood would be melted off and it'd pretty much be at operating temperature at startup.

All that said, we are starting to have overnight lows in the -10 range, and I still haven't plugged in my PSD...

 

[Donsbad89]

My truck is a 92. I left it plugged in all night last night. The change was amazing. Fired right off and I had good heat in 1-2 min.

 

[MIDNIGHT RIDER]

Although I have no doubt that my engines can and will start un-plugged in below-zero temperatures, if at all possible, I have them plugged in at least a couple hours before starting on any night it gets close to freezing/32*.


I can't see it being good for seals and such to be ice-cold when the engine is cranking.