use block heater for mpg?

[npauli]

Has anybody tried using the block heater (probably on a timer) for every cold start in the morning, rather than just when it's really cold outside?

Every decent article on fuel economy is quick to point out that engines work better warm and you pay a penalty for every cold start. In theory, the block heater should help there.

BUT...
1) the heater uses electricity which also costs money
2) electricity + heat + water + metal = corrosion, so I'd imagine excessive heater use costs you something in wear & tear.

[Mark Rinker]

Interesting point, and I agree that there is some temperature threshold that using the block heater is beneficial, offsetting the cost of the electricity in fuel savings AND reduced wear and tear from cold starts.

Our rule here is anything below 10F.

Admittedly, we break the rules often, because the Duramaxes are such great cold weather starters. Anther problem is no electricity close by to the area where they are parked, and the closest plug isn't my own meter.

On those days, we drive the trucks home and plug them in when we can. Thats the greatest...using my employee's electricity... :)

[Duraswede]

I can share my experience about block heaters..
Here in Sweden it's very common to use them, nearly every car has one, and not only an engine heater but also an outlet inside the vehicle for a coupe heater.
At my work we have outlet "poles" on the parking, they have a timer and start 2 hours before we leave for the day, so i have a warm and nice car to drive home in.. and the electricity is for free:)
I use the heater in the mornings as well, but then i have to pay for the electricity:( so i use it only when it's below freezing, at work i use it even a couple degrees over, but it's worth the cost to come to a warm car, without snow on the windows, and a warm seat!

i found some info about our systems in english: http://www.calix.se/consumer/index.asp?lang=UK

[Shed]

I can't imagine that the price is that high for a "cold" start. Been known to be wrong though!

I like a few on here have had problems with the block heater being plugged in above a certain temp. Last winter I had my son "help" me by plugging in the truck for me when it was a low of 40 degrees. Needless to say I threw a code, and a few weeks later ended up replacing a controller. Not sure if these were exactly realted but it did'nt help matters! He's a good boy, just wanted to help dad.

Shed

[Duraswede]

I can't imagine that the price is that high for a "cold" start. Been known to be wrong though!

I like a few on here have had problems with the block heater being plugged in above a certain temp. Last winter I had my son "help" me by plugging in the truck for me when it was a low of 40 degrees. Needless to say I threw a code, and a few weeks later ended up replacing a controller. Not sure if these were exactly realted but it did'nt help matters! He's a good boy, just wanted to help dad.

Shed
well, i dont think it has to do with the warm engine, it must be some electrical fault, most likely the heater cord isolation can be damaged and "leaking" AC-current to some low voltage circuit, it's just a thought, if you dont have a GCFI on that outlet then you mayby won't notice it, until it becomes serious enough.. i havn't used my block heater on the duramax yet but i installed one on my previous chevy 6.5TD -00 and used it frequently, it came up to temp a lot faster than to just cold start it below freezing..

[DmaxMaverick]

On "earlier" Duramax trucks (not sure if/when they "fixed" it), the PCM would fault if the block heater was used while the ambient temp as within a certain range. About 30-50°F, IIRC. It isn't a problem with the heater or electrical power cord (although they can fail), but the interpretation by the PCM. It seemed the PCM logic had issues with the difference of temp samples taken by the various sensors, including, but not limited to, the ECT, IAT, and trans. temp. Something in the PCM just didn't add up, causing a logic fault.

[Duraswede]

On "earlier" Duramax trucks (not sure if/when they "fixed" it), the PCM would fault if the block heater was used while the ambient temp as within a certain range. About 30-50°F, IIRC. It isn't a problem with the heater or electrical power cord (although they can fail), but the interpretation by the PCM. It seemed the PCM logic had issues with the difference of temp samples taken by the various sensors, including, but not limited to, the ECT, IAT, and trans. temp. Something in the PCM just didn't add up, causing a logic fault.
ok, that was new to me, mayby i should be careful with my heater because i have already had a lot of electronic problems..
so it is because the various temp sensors dosn't "see" the same temperature at startup?

[DmaxMaverick]

I doubt any damage is happening, other than a confused PCM. I haven't heard of any permanent effects. I've never used my Duramax block heater, and never felt the need to. It's had to make several starts at about -20°F with no problem. Above freezing, I don't even wait for the GP cycle to complete. Key from off to crank, and it fires right off. I've considered installing a cutout for the GP circuit for warmer times, which is most of the year in California. My 6.2's have never needed any glow during summer months to start well, but they've all been manually controlled after a time (out of warranty). I haven't had to replace any glow plugs after the modifications. I've pulled and tested them periodically, and they all appear new and function normally. So far, I've replaced 3 GP's on the Duramax. At $15 each, it's getting my attention. I've considered a resistor bypass to address the PCM monitoring (CA emissions). Same for the intake heater.

[rapidoxidationman]

Do all these engines come from the factory with a block heater? I've looked (not very closely) at mine and have not seen a plug... I've only owned it for a day though. Where ought I look for one?

Thanks!
ROM

[jbplock]

Do all these engines come from the factory with a block heater? I've looked (not very closely) at mine and have not seen a plug... I've only owned it for a day though. Where ought I look for one?

Thanks!
ROM

ROM, Yes they are standard .. look for it on the passenger side of the engine compartment .. if it's never been used the cord will tied to the body a little forward and below the battery ... I bought mine out to a receptacle on the front air dam
http://thumb8.webshots.net/s/thumb4/1/10/18/101311018NwYsMY_th.jpg (http://rides.webshots.com/photo/1101311018033933568NwYsMY) http://thumb8.webshots.net/s/thumb4/0/92/74/101309274UuGtaS_th.jpg (http://rides.webshots.com/photo/1101309274033933568UuGtaS) http://thumb8.webshots.net/s/thumb4/0/95/5/101309505ZPCmZN_th.jpg (http://rides.webshots.com/photo/1101309505033933568ZPCmZN)
(click pics to enlarge)

:)

[rapidoxidationman]

Thanks JBP! It is exactly where you said it would be, and is still tied to the wiring harness. Must be a good sign that these trucks are easily started in cold weather. I'm willing to bet my 6.5 won't start this morning unless I plug it in (-15*F last night), so I'm looking forward to seeing how the DMax fires up cold.

Thread hijack off...

ROM

[npauli]

For what it's worth, I just got a ScanGauge for christmas, which can display realtime fuel consumption, among other things. Here's a few numbers to consider:

When warm, my truck uses about .3-.4 gal/hour at idle.
When cold soaked at ~ 20F, it uses more like 1.5 gal/hour
On a similar cold morning with the truck plugged in for a few hours (coolant and oil heater), it runs more like .7 gal/hour.

That's enough to convince me to plug in when I can for at least a few hours.

I'm not quite to the point where I can tell you how long to plug in your truck for the current temp, fuel price, and electricity price. But it seems to me like the diesel you save by plugging in is probably about enough to pay for the electricity you use - at least if it's cold enough Having a warmer and happier engine is just a bonus.

[chrisinkanata]

Living in eastern Ontario, I find I try to use my block heater when it's below about -10C (14F). As I type this, it's -24C (-12F) out. I know the truck will physically start if not plugged in, but with non-synthetic 15W40, my concern surrounds how long it takes for the oil pressure to come up. Most often, the check oil light message will display for several seconds when it's really cold like today. If I ever had to consistently start it at these very cold temps without having it plugged in, I'd be using synthetic.

Chris

[leolkfrm]

I've had an 03 for 1 yr now, and just started to use the block heater. the zero degree weather won't let me start it with the remote. couldn't stand the idea of a 1000 watt block heater running all the time, soo....i rigged up a remote control 13amp switch with a light. 1 hr before I want to start the truck i hit the remote for the heater, 10 min before i go out i hit the remote for starting the truck, it has been starting on the first crank.
I have a grill cover on it, to maintain temps, above 20 i open the Velcro flaps

[Luis]

I've never had to use my block heater since 2001; until now...when the temp was 22 deg F the other morning she had trouble starting. I let her warm up and went on my way...came home and my AmsOil (15w-40 HD Marine & Diesel 100% synthetic) had arrived...change the oil and filter...located the plug and plugged her in...next morning 8deg F and she fired right up...oil pressure was up right away and the battery guage went up right away...yesterday morning started her up and the temp was 2deg F...again she fired right up...went out today and purchased a HD outdoor timer so I can save a little money on electricity...It was nice and quiet too!!!

I guess the 'ol glow pluggs are going south...

Mileage is 126K with new injectors at 121K...