resmas
Alaska
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Joined: 05/05/2008
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This is my first winter owning my 2009 GMC 2500 Duramaxx. I bought it in July, and until recently, the MPG has been above 16mpg. It drops when I tow, but has always regained back above 16mpg. Then it got colder (not COLD - we haven't dropped below zero yet) and the mpg started dropping like a rock. Then it snowed, and I have been in 4wd constantly for a week. I have NO traction without 4wd, even with studded/siped tires and 360lbs of sandbags over the rear axle. The truck is kept in a heated garage (50-60 degrees) and is only driven to school and the grocery store. Unfortunately, I don't get to run at 65mph for any distance very often.
So do you think my MPG is dropping because of cold weather or is it my DPF not getting "cleaned out"?
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skyflyer
iowa
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Joined: 09/03/2001
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Yes your mileage will drop in the winter.
Once the stations switch to winter blend to help keep from gelling.
Don't forget to add power service or similar each time you fill up.
Bob and Tammy
1998 31 fls golden falcon
2006 chevy silverado duramax
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resmas
Alaska
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The stations up here switched over blends some time ago. I do put additives in, but I don't use the block heater or have the winter cover on the grill yet. My DH is hedging on the winter cover - he is afraid the GMC provided cover will scuff the truck's finish. He zip ties a piece of cardboard inside the grill of his Dodge in the winter, it works fine, so he's wanting to do that to mine. We've actually had a diesel truck for over 10 years, BUT this is the first time we've had a diesel as a "daily-driver" in the winter. DH's truck pretty much sits all winter - only gets driven if conditions aren't safe for his 36mpg commuter car, so it is hard to track the effect on it's MPG.
I am just surprised how fast the MPG is dropping - I'm pretty sure I'll be at less than 10mpg before winter is up. I had anticipated it dropping some, but not like this!
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Golden_HVAC
Fulltime, CA, USA
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Joined: 08/19/2003
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Hi,
Using 4 wheel drive usually means a big drop in fuel mileage.
Also during warm up, sometimes the timing is set in a way that allows more fuel to be burned to warm up the engine.
What tire pressure are you running?
Unless your truck is fully loaded, I would not want more than about 50 PSI in the tires, so they will be a little softer and more traction will result. This will not help your fuel mileage either, but might keep you out of a ditch.
I would put in cardboard or something to keep the radiator from freezing. I agree that the bonnet might damage the paint, especially if ice forms on the cloth, and then vibrates (like a diesel will never vibrate?). You will remove enough heat from the cab heater to keep the engine from overheating.
I have a friend who designed the little 3.9L engine for the Knotts Berry Farm Galloping Goose. He says Cummings requires 8 square inches of radiator space for each horsepower, about 100 in his case, so 2 rows thick works out to 400 square inches. This is 20" square, and he thought that the radiator was tiny, so he built a shroud. It turns out that the engine never warms up, the amount of horsepower to move a 50 passenger bus on a level railroad track is only about 20 HP, so it stays cold, even in 75 degree weather without a heater core into the bus. Only a 1/4" hole in the thermostat bypass is cooling the engine.
The fuel gauge refused to budge too. In a week, it only took about 20 gallons of fuel, while running on the big old Reo inline 6 it would use the 55 gallon tank of gasoline each day. Knotts steam train uses about 300 gallons a day in fuel. Guess what they run all winter? Well they still run the steam train on the weekends in the winter.
Good Luck,
Fred.
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I am still wayne_tw
everywhere
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You are doing short trips in cold weather which will mean lower mpg's.
You are driving in 4 wheel drive which will mean lower mpg's.
you are hauling almost 400 lbs in the back which will mean lower mpg's.
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glazier
Kentucky
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Joined: 01/18/2009
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Yes mileage will drop some in the winter. I don't think the short trips will be that much of an issue on the DPF, it will let you know if it is. Drive it how you need to, that's what you bought it for. If that truck can't get the job done without a bunch of hassel, you don't need it IMO.
2010 Jayco Eagle Super Lite 31.5 FBHS
08 Chevy 2500HD LTZ Duramax CC/SB/4X4
Reese Signature Series Hitch
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downtheroad
Puget Sound
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Joined: 02/18/2003
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skyflyer wrote:Yes your mileage will drop in the winter.
Once the stations switch to winter blend to help keep from gelling.
True.
Don't forget to add power service or similar each time you fill up.
Why does he have to do this? Enlighten me.
"If we couldn't laugh we would all go insane"
GMC Duramax/Allison (LBZ)
Komfort 277TS Our Rig Picture
Reese Dual Cam HP
Lots of other stuff nobody cares about
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david_42
Oregon
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You can expect a 8-10% drop in mpg on a winter blend and an additional 10% while running in 4WD vs rear only.
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christopherglenn
a little over an hour from Yosemite
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when the weather turns cold, the truck tenhs to keep the grid heater on all the time, this is a emission thing. running several hundred watts of heater, and delaying the timing plus the fact the a cold block is less efficent then a hot block, the mpg's crash in the winter. I go from babying it to about 22mpg to babing it at 18.. Normal summer driving is 18 to 19 average, winter is 16 to 17.
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skyflyer
iowa
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downtheroad wrote:skyflyer wrote:Yes your mileage will drop in the winter.
Once the stations switch to winter blend to help keep from gelling.
True.
Don't forget to add power service or similar each time you fill up.
Why does he have to do this? Enlighten me.
I guess I should have been more specific.
DURING COLD WEATHER SOME DIESEL OWNERS RECOMMEND ADDING POWER SERVICE OR SIMILAR ANTI GELLING AGENTS TO FURTHER PROTECT AGAINST GELLING.
Some owners feel usld gell's quicker.
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