Plug in Engine Block Heater for Fuel Savings vs Electrical $

fastring · **Posted:** Mon Dec 05, 2011 12:10 pm

I did a search and didnt find anything.

Q1. Does anyone plug in their factory block heater with the expectation that they are saving $ in diesel fuel vs electrical costs?

Q2. How long do you set your timer for (that you plug the heater into) for optimum savings?

I'm in San Diego, its actually been in the low 30s this week (Valley Center, CA part of San Diego) and the PowerStroke and the CRD both start fine. The Jeep has brand new metal glow plugs all around, starting isnt an issue, but I'm a mpg optimizer and am interested if anyone has run a scanguage to see what the CRD fuel consumption is at idel cold vs warm and what the amount of time you'd need to preheat the block is to hit the ideal block temp for mpgs.

papaindigo · **Posted:** Mon Dec 05, 2011 12:16 pm

Had not really thought about diesel vs electric power use for the block heater, in fact I'm not even sure how much power the block heater consumes. I don't bother to plug it in unless the overnight temp is going down into the 20s F in which case its use helps with the cab heat and makes a big difference in engine warm up time on short (10 mile or so) low speed (45mph max and 20mph average) commutes.

Radman · **Posted:** Mon Dec 05, 2011 2:50 pm

Low 30's is not cold. I do not plug unless below 20. Even your Glow Plugs are not really used at those temperatures. I would not worry if living in areas where temps do not get below freezing.

badassjeep · **Joined:** Tue May 10, 2011 9:18 am **Posts:** 66

Radman wrote:

Low 30's is not cold. I do not plug unless below 20. Even your Glow Plugs are not really used at those temperatures. I would not worry if living in areas where temps do not get below freezing.

I assume you mean 20 below? (-20)
My Jetta TDI has started fine at -30 F without being plugged in (it was outside).
This will be my first winter with the Liberty, since it already has a coolant heater I had planned on using my timer and allow it to run for a hour when below 0. Not only for fuel savings and heat but to reduce stress on the engine.

At 8 :2cents:

a kilowatt, it would not take much fuel saving to make up for it.

NotPicky · **Posted:** Tue Dec 06, 2011 2:38 am

I plug my diesels in around 10 degrees. Not to save fuel or shorten warm up time but to aid in engine longevity.

rjmaype · **Posted:** Tue Dec 06, 2011 9:15 pm

I plug in at 20 degree with a one hour timer.

The F350 7.3 PS gets two hour timer.

ColoradoCRD · **Joined:** Sun Dec 10, 2006 9:25 am **Posts:** 60

Yes, I plug in with the expectation that I realize a net savings for the cost of diesel fuel vs cost of power. I don't think there is a way of gathering sufficient data to accurately measure the fuel saved vs. the electrical power used. As others have reported, I measured the draw using the block heater at 400 watts. Additionally, it would seem that wear and tear is reduced considerably when using the heater.

I get into a daily habit of plugging in for a 6 to 7 month period and use a conventional household timer. 1 to 1 1/2 half hours is good. More time than that probably results in diminishing return. There is a noticeable benefit with as little of 20 minutes of heater time.

My jeep is not in a heated space where it frequently hits below 0F degrees, and the coldest night time temperatures are in the -10F to -25F range.

As another heads up, if you use the block heater frequently, the cord experiences fatigue to the extent that the heater will stop working. I had to cut the last few inches off of mine and install a new plug.

nursecosmo · **Posted:** Fri Dec 09, 2011 12:10 pm

Aside from the convenience of easy starts, the most important reason for plugging in is engine life. I left my rig unplugged last night for experimentation. This morning it was -10F by my thermometer. I hooked jumpers up from my Ram with twin high amperage batteries to the Liberty, just to verify that my recent cold start problems were not related to a weak battery(It has a pretty new Diehard P-1). It cranked ~10 seconds before catching on one cylinder, then two, three, etc. Once it was running on all four, it was really RATTLING as these little beasts are wont to do when cold. It is not something I'd recommend on a regular basis. Just think about the stress on the starter, shrunken main bearings, delicate rings and scrapers trying to push peanut butter up and down the cylinders, not to mention the poor turbo charger trying to get oil the consistency of thick molasses through the itty, bitty lube holes.

Big Montana · **Posted:** Sun Dec 11, 2011 8:30 am

I plug mine in too. Anywhere around 40F or below. I have a timer for 2 hours and I get a smooth start. My battery is 6 years old, so I know the warm block helps. When I leave work, it turns over forever before it catches because I can't plug it in.

As for fuel economy, I'm not sure any steps can help against winter diesel. My MPGs drop off by about 3-4 MPG once it gets cold in Michigan. I need to remember to use powerservice to see if that helps.

My cord does look a little rough after six years. That could be a concern as was stated before.

CRD Joe · **Posted:** Sun Dec 11, 2011 11:21 pm

I try and plug mine in an hour or two before I plan on driving. Ive heard that if you leave them plugged in all the time the heater unit will burn out.

Any ideas on that?

tregrrr · **Joined:** Mon Oct 10, 2011 2:37 pm **Posts:** 59

I have to smile at some of the southern members referring to cold starts. I lived in real cold for years and up in Ft McMurray Alberta, you plug that cord in.

-40 sucks, no two ways about it.

How much is the peace of mind that you aren't murdering your engine worth?? I am not sure what the cut off is temperature wise for a cost benefit analysis, but electricity is cheap. This Christmas I will flip my Grandmother 20$ and not think twice about electricity waste since it takes way more greenhouse gas to smelter and forge the bits which will otherwise sound like they be dying the painful death.

I always plugged my gassers in at -20C (-4F) just for my own presence of mind(0w30 synthetic made easy work of most any start), but I plan to give the CRD cord love much earlier.

nursecosmo · **Posted:** Mon Dec 12, 2011 8:19 am

tregrrr wrote:

I have to smile at some of the southern members referring to cold starts. I lived in real cold for years and up in Ft McMurray Alberta, you plug that cord in.

-40 sucks, no two ways about it.

How much is the peace of mind that you aren't murdering your engine worth?? I am not sure what the cut off is temperature wise for a cost benefit analysis, but electricity is cheap. This Christmas I will flip my Grandmother 20$ and not think twice about electricity waste since it takes way more greenhouse gas to smelter and forge the bits which will otherwise sound like they be dying the painful death.

I always plugged my gassers in at -20C (-4F) just for my own presence of mind(0w30 synthetic made easy work of most any start), but I plan to give the CRD cord love much earlier.

X2. If one has never experienced it, it cannot be explained.

Dave01 · **Posted:** Mon Dec 12, 2011 9:40 am

About the heater burning out with use, any resistance heater will burn out over time but I wouldn't base your usage on that, just use it when you feel you need it.

The stock heaters are only 400 watts, so they really don't use much power, I don't think you'll see much impact on the electric bill using it a few hours a night.

This is my first winter with the Liberty, so I'll have to experiment a bit. I think I'll start with running it 3 hours on the timer when temps are below 20 F and see how it goes.

Nursecosmo, I agree the heater helps with engine life but a bit of diesel rattling won't hurt the engine. It sounds violent but isn't doing any damage. Also, on the oil being like peanut butter, if you use a 0W or 5W synthetic with excellent cold pour specs the oil will flow ok even on cold starts. I'm using Mobil 1 5W40 Turbo Diesel Truck but haven't looked at the cold pour specs, will do so today.

striperman36 · **Posted:** Mon Dec 12, 2011 10:46 am

4 hour timer , any night when below 32F is expected. Original battery. and no rattlin.

ATXKJ · **Posted:** Mon Dec 12, 2011 10:11 pm

400 watts overnight 8 hours = 3200 watts = 3.2 KWH ~ 15 cents...... how much $3.65 diesel does it take to recoup 15 cents of electricity........

nursecosmo · **Posted:** Mon Dec 12, 2011 11:25 pm

Dave01 wrote:

Nursecosmo, I agree the heater helps with engine life but a bit of diesel rattling won't hurt the engine. It sounds violent but isn't doing any damage. Also, on the oil being like peanut butter, if you use a 0W or 5W synthetic with excellent cold pour specs the oil will flow ok even on cold starts. I'm using Mobil 1 5W40 Turbo Diesel Truck but haven't looked at the cold pour specs, will do so today.

Ha ha, that's funny. Leave it unplugged when the temperature is -20f and then talk to me about how benign the rattle is. Set your quart of M1 0-40 on the porch overnight next time you get nice nippley -40F norther. pour point simply means that it isn't solid at that temp. M1 0-40 is completely solid at ~-70f. It does not suddenly freeze like water does at 32f, it progressively thickens until it becomes non-fluid. Even though the average deep freeze only goes down to about -10, put your oil in there for a few hours and then try to add some to your engine.

Peanut butter is of course an exaggeration but it is certainly not adequately lubricating your engine until warmed up considerably.

http://en.wikipedia.org/wiki/Pour_point

tjkj2002 · **Posted:** Tue Dec 13, 2011 1:58 am

nursecosmo wrote:

Dave01 wrote:

Nursecosmo, I agree the heater helps with engine life but a bit of diesel rattling won't hurt the engine. It sounds violent but isn't doing any damage. Also, on the oil being like peanut butter, if you use a 0W or 5W synthetic with excellent cold pour specs the oil will flow ok even on cold starts. I'm using Mobil 1 5W40 Turbo Diesel Truck but haven't looked at the cold pour specs, will do so today.

Ha ha, that's funny. Leave it unplugged when the temperature is -20f and then talk to me about how benign the rattle is. Set your quart of M1 0-40 on the porch overnight next time you get nice nippley -40F norther. pour point simply means that it isn't solid at that temp. M1 0-40 is completely solid at ~-70f. It does not suddenly freeze like water does at 32f, it progressively thickens until it becomes non-fluid. Even though the average deep freeze only goes down to about -10, put your oil in there for a few hours and then try to add some to your engine.

Peanut butter is of course an exaggeration but it is certainly not adequately lubricating your engine until warmed up considerably.

http://en.wikipedia.org/wiki/Pour_point

You need to buy better oil.I've changed oil in -30 degree weather before and had no issues pouring in 10 gallons of 15w-40 dino diesel oil even at that temp.

Dave01 · **Posted:** Tue Dec 13, 2011 9:47 am

Good points by you, and it sounds like you're in a much colder climate than me. We get some -10's every year, -20 is pretty unusual, and never a -40 (unless you are talking about wind chill).

I won't leave it unplugged at 10 F, certainly not -20 F, when it's in my driveway. When I'm somewhere that I can't plug in I'll cross my fingers. I wasn't saying not to plug it in, just that when I can't, and it rattles like crazy, I'm not worried I'm taking 10,000 miles off the life of the engine.

I've done some of those oil pour tests at about -10 F. I've never tried Mobil 1, but did it with Valvoline synthetic 5W40, Amalie Fleet 15W40 conventional, and Amsoil Diesel and Marine Synthetic 15W40. The Amalie was like heavy molasses, made us wonder why our trucks would ever start at all, the Valvoline poured easily, the Amsoil, despite the higher viscosity rating, poured the easiest. I don't know what they would have looked like at -40, probably not pretty. The Amsoil rep I was working with educated me on looking at pour specs, not just viscosity rating, and he was right as some 15W oils have better cold pour properties than 0W oils.

We agree, plug in when possible, no argument from me! We're starting to finally get cold around here, maybe I'll take a video of a morning start with and without plug in for comparison.

nursecosmo · **Posted:** Tue Dec 13, 2011 12:29 pm

Sorry, I'm not trying to be a troll, I was just trying to make the point that cold starts have an effect on the engine. I don't think that it will make tremendous impact on the rebuild interval but it isn't great for it either. It looks like everyone agrees that extreme cold starts should be avoided if possible. In the real world however, that isn't always the case.

tjkj2002 · **Posted:** Tue Dec 13, 2011 12:37 pm

nursecosmo wrote:

Sorry, I'm not trying to be a troll, I was just trying to make the point that cold starts have an effect on the engine. I don't think that it will make tremendous impact on the rebuild interval but it isn't great for it either. It looks like everyone agrees that extreme cold starts should be avoided if possible. In the real world however, that isn't always the case.

You could be like my father and between Oct-April his F250 SD and all tractors never get shut off besides when he has to change the oil or they break down.Not real fuel saving but eliminates cold starts.

Plug in Engine Block Heater for Fuel Savings vs Electrical $

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