Leaving a block heater plugged in

[SnowDrifter]

Rather than putting it on a timer, what would happen if I were to just leave a block heater plugged in? Or maybe I should phrase this as.... What are the effects of higher temperature over time in a non-running engine?

What could it do to the oil / coolant / anything else?

 

[sir1900]

Leaving it plugged in will do nothing for the vehicle. It's a waste of energy and you are essentially throwing your money away. In extreme cold, you only need to have it plugged in for a maximum of four hours.

 

[DoubleWasp]

Depends how extreme. In some places, they won't even shut off the engine if it's too cold.

 

[gpguy]

Nothing but make your wallet lighter!! It doesn't get hot enough to damage any coolant or oil.


Ive always lived in the north where plugging in is part of winter. Electricity is not cheap here and Ive used a timer for years. I have a good one mounted to the wall next to my outdoor plug. Comes on 3.5 hours before starting my truck...never had a problem.

 

[lars11]

Exactly, the power is not enough to heat the block to even nearly running temps. And the cooling system will also start to circulate and keep temps down a bit. So not to worry, people forget to unplug the heater all the time and no problem.
But you will pay for the electricity though.

 

[901Memphis]

The effect is your car is always ready to go plus a lighter wallet. You may also wear out your block heater depending on how nice it is. Are we talking oil heater or coolant or both?

 

[Olas]

Originally Posted By: 901Memphis
The effect is your car is always ready to go plus a lighter wallet. You may also wear out your block heater depending on how nice it is. Are we talking oil heater or coolant or both?


I think they're talking both. If it was sold as/referred to as an oil heater, or a coolant heater, then you could expect it to do that particular task.
In effect a block heater is also a head heater, manifold heater, everything-else-under-the-bonnet-heater.
(notwithstanding using it to heat a bare block, but not sure why you'd do that

 

[Lapham3]

I love that- "under the bonnet". Most 'freeze plug' heaters are 400w-some 600w-and lower radiator hose-if possible to use. The circulating 'tank heaters' are generally 1200w and get things hot in a hurry-even a big V8. I never worry about a few $ for the fact that they make things better for the car and the occupants. None of them get the engine truely 'hot'-no worries-

 

[Jarlaxle]

IIRC, the heater on my wife's Blazer is 800 watts. The one on my F-350 was 1000W.

There is no reason to plug them in more than a couple of hours in even extreme cold!

 

[xxch4osxx]

We plug the big trucks in as soon as we get back at the end of the day in the wintertime. Only on friday nights do we not plug them in. The boss will plug them in on sunday night. It is really hard on them to start cold at -20 and below.

 

[Chris142]

my pickup came from alaska.it has 2 block heaters in it.im sure that its been plugged it for long periods.ive never used them here

 

[abycat]

Originally Posted By: gpguy
Nothing but make your wallet lighter!! It doesn't get hot enough to damage any coolant or oil.


Ive always lived in the north where plugging in is part of winter. Electricity is not cheap here and Ive used a timer for years. I have a good one mounted to the wall next to my outdoor plug. Comes on 3.5 hours before starting my truck...never had a problem.



Hey neighbor. I have an oil pan heater, block heater and a battery warmer in my truck. The car has a block heater only.

 

[WobblyElvis]

My 4 cylinder car has a 350 watt block heater and I have measured the temp change after being plugged in for 3 hrs during cold temps. 35F rise at most.

 

[JDW]

Hats off to you guys living in that cold ! Gets below 70F I have the chills

lol

 

[Jarlaxle]

Originally Posted By: WobblyElvis
My 4 cylinder car has a 350 watt block heater and I have measured the temp change after being plugged in for 3 hrs during cold temps. 35F rise at most.


That's a half-power heater...then again, a 35 degree boost should be plenty to start an engine.

 

[y_p_w]

I've heard of outlets and/or power cords being available in outdoor parking areas in certain areas where it's cold. In that case, I'm not sure why anyone would necessarily want to go out and plug it in 2 hours before starting rather than just plugging it in and leaving it that way. If it's not costing you any money directly, why not just leave it in?

Here's a motel in Fairbanks:

Or Sweden:

 

[Lapham3]

A lot of folks think that if it starts, all is well. As said, it's hard on the mechanicals in extreme cold. I plug my stuff in to mitigate that higher wear and the residual heat can help everything underhood. I'll even plug my old cars in before starting them up after months of winters nap-never had an engine failure in almost 50 years and that's part of it. I had one block heater fail after 20 years in my El Camino, but probably 20 others that never gave any problem. You guys that live in hotland have other issues! Dan Mpls. MN.

 

[Garak]

Originally Posted By: y_p_w
I've heard of outlets and/or power cords being available in outdoor parking areas in certain areas where it's cold. In that case, I'm not sure why anyone would necessarily want to go out and plug it in 2 hours before starting rather than just plugging it in and leaving it that way. If it's not costing you any money directly, why not just leave it in?

Very few people are going to run outside to plug a vehicle in during the middle of their shift, or wake up four hours early in a motel, I'd agree. At home, it's common for people to use timers and/or temperature sensors.

 

[PFP]

Regarding the parking lot power outlets for block heaters, the way most of these work is by a temp sensor at the main, which cycles the outlet on+off, at a frequency determined by outside temp. for example, if the outside temp is -15, they are on for 10 min, off for 10 min, if it is -20 they are on for 10, off for 5 and if below -25 on continuously. Otherwise, lots of power is wasted. With this cycling, some power is saved and people can come and go at different times. Any car, no matter the temp, needs the heater activated for a max of 4 hours before starting. Not only does the block heater aid starting, but its REAL benefit is that the heater starts pumping out warm air a lot sooner. For most of us, that is the real plus!

 

[y_p_w]

Originally Posted By: PFP
Any car, no matter the temp, needs the heater activated for a max of 4 hours before starting. Not only does the block heater aid starting, but its REAL benefit is that the heater starts pumping out warm air a lot sooner. For most of us, that is the real plus!

Yeah - I've heard that instant on heat to the passenger compartment is why most people want to use block heaters. Easier starting and oil circulation are certainly important, but not necessarily critical if it still manages to start. I don't drive in near freezing weather often, but when I have I remember just waiting forever for the heat before leaving.

I've heard one claim that perhaps most vehicles (even in temperate climates) could make do with 30 wt oil and a block heater if they otherwise call for 5W-30 or 10W-30. I think they might be protected as well, but the multiweights are supposed to provide for better fuel economy.