When to plug in block heaters
Senior User
Joined: Dec 2005
Posts: 283
Likes: 0
From: Vero Beach, FL
In Alaska, the public service announcement always said "below 20". I always plugged I once it was consistently in the mid 30s for an overnight low. While it does help your heater kick in more quickly, it is also just better for your engine at initial start up, because everything is warmer.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
To a certain extent they do, you bet. Oil turns to thick sludge when it gets cold and the resistance to cranking is a lot higher. Another thing that helps (or required) in brutal cold is remove the battery and bring inside. This has other issues with modern vehicles, and inconvenient at best but it helps with cranking. It pays to monitor and keep batteries fully charged and maintained in the warmer months, that's when damage occurs, but it shows up the first cold snap. Cables and connections too, maintenance is a b#%+ in the cold.
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Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
If its factory equipped the recommended temp to use it is in that lil black book in the glove box....who puts gloves in there anyway? I usually plug heaters in when it hits 20-25*f Makes for faster warm ups, easier on the engine too.
Careful...remember to unplug it. I put a post-it on the dash gauges as a reminder as I have forgot. I position the plug in such a manor that if I do forget it will come apart without causing damage. Always plug it into a known good GFCI protected circuit.
Careful...remember to unplug it. I put a post-it on the dash gauges as a reminder as I have forgot. I position the plug in such a manor that if I do forget it will come apart without causing damage. Always plug it into a known good GFCI protected circuit.
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Postmaster
Joined: Apr 2008
Posts: 4,724
Likes: 4
From: Rogersville, TN
As long as your glow plugs and relay are working good you shouldn't have any problems starting it. It will just take it longer to warm up and run properly.
Cargo Master
Joined: Jul 2003
Posts: 3,358
Likes: 250
on my diesel truck I start plugging in around 30F* and on my gas I start plugging in around -10f*. I've started my diesel without being plugged in down to the high teens and the gas with as cold of temps as I've ever seen in IA, but being plugged in helps the engine warm up faster and IMO is easier on them.
Freshman User
Joined: Nov 2012
Posts: 28
Likes: 0
My '06 6.0 had a stiction problem so I started plugging it in when the temperature was going to approach freezing. Years ago I started it (once!) without being plugged with the temp in the mid teens. Being plugged in helps the engine turn over faster, warm up quicker, and is easier on both the batteries and the engine. (BTW, this will be my first winter with lighter oil; a synthetic blend 10w-30. I had been using 15w-40 year 'round for the past 7 years.)
Also, my electric bill took a jump with the block heater running full blast for 8 or more hours every night. I bought a timer to start the heater about 2 hours before I had to start the truck. That lowered the electric bill.
I also bought a temp switched plug on Amazon for heating livestock water troughs etc. It turns on about 35deg and off at 45deg. So with the timer and the temp switch, I plugged the truck in every night (in cold weather) and started the truck in the morning.
Also, my electric bill took a jump with the block heater running full blast for 8 or more hours every night. I bought a timer to start the heater about 2 hours before I had to start the truck. That lowered the electric bill.
I also bought a temp switched plug on Amazon for heating livestock water troughs etc. It turns on about 35deg and off at 45deg. So with the timer and the temp switch, I plugged the truck in every night (in cold weather) and started the truck in the morning.
Posting Guru
Joined: Jan 2012
Posts: 1,176
Likes: 4
From: Indiana
I'm a cheater- I have an outdoor receptacle that is wired separate for each plug just for my truck. The bottom plug is where I plug in my block heater. The way I have it wired is: from my breaker box to a timer to a wall switch indoors to an outdoor temperature switch to the outlet. That way, as long as it is between the hours of 7:00 AM and 9:00 PM AND the wall switch is on AND it is 10 degrees F or less outside, the outlet gets power, thus if the truck is plugged in, the block heater is working.
The top plug on the outlet is just wired to an indoor wall switch- I have a small electric heater in the truck that gets plugged in there. That way, when I get up in the morning, I just flip the switch, and in the time it takes me to shower and get dressed, I always go out to a pre-warmed-up cab.
I know, I'm a lazy ol' sissy...
The top plug on the outlet is just wired to an indoor wall switch- I have a small electric heater in the truck that gets plugged in there. That way, when I get up in the morning, I just flip the switch, and in the time it takes me to shower and get dressed, I always go out to a pre-warmed-up cab.
I know, I'm a lazy ol' sissy...
Hotshot
Joined: Nov 2008
Posts: 15,014
Likes: 35
From: Semper Fi tell I die!
I'm a cheater- I have an outdoor receptacle that is wired separate for each plug just for my truck. The bottom plug is where I plug in my block heater. The way I have it wired is: from my breaker box to a timer to a wall switch indoors to an outdoor temperature switch to the outlet. That way, as long as it is between the hours of 7:00 AM and 9:00 PM AND the wall switch is on AND it is 10 degrees F or less outside, the outlet gets power, thus if the truck is plugged in, the block heater is working.
The top plug on the outlet is just wired to an indoor wall switch- I have a small electric heater in the truck that gets plugged in there. That way, when I get up in the morning, I just flip the switch, and in the time it takes me to shower and get dressed, I always go out to a pre-warmed-up cab.
I know, I'm a lazy ol' sissy...
The top plug on the outlet is just wired to an indoor wall switch- I have a small electric heater in the truck that gets plugged in there. That way, when I get up in the morning, I just flip the switch, and in the time it takes me to shower and get dressed, I always go out to a pre-warmed-up cab.
I know, I'm a lazy ol' sissy...