2008 2500 hd

[sdc eastern Iowa]

Like the subjest shows I have a 2008 Chevy 2500 HD diesel W./allison. I know whoopdee doo. My question is this. Why in the winter do I get about 8 to 9 MPG and in the summer around 18. The truck does not warm up until I drive 20 miles and I work 16 miles from home. It does not make any difference if I warm it up in the driveway and this year I installed a winter front. No difference there either. I use around 75 bucks of diesel every 7 to 9 days and am getting tired of this. The dealership doesn't have an answer, they just tell me the computer says it should be getting 15 to 16 in the winter. Anybody out there have the same problem? I kinda want my Ford back.

 

[Hurst]

With newer diesels that have DPFs on them, they will not get very good mileage doing short drives, especially cold. The reason is the truck is doing more active regenerations, where it uses some fuel in the exhaust to burn in the DPF so it will burn off the collected soot. In addition to that, EGR cycles will be greater when the engine is cold from what I understand, and diesels will not run all that efficiently when cold. I would try to get a block heater for the truck and put it on a timer to run a few hours before you head out in the morning. Also, I would consider shortening your oil change intervals, or better yet, getting a used oil analysis done to see how much fuel dilution you have. Cold running can cause increased fuel dilution, and if the truck performs active regeneration by injecting diesel into the cylinder during the exhaust stroke, that can also cause more dilution with every active regeneration. This would be my guess for getting bad mileage in the winter. On top of that, winter fuel tends to have less BTUs if you live somewhere cold where they winterize the fuel, which it sounds like you do.

Hurst

 

[John M]

How are you figuring your mileage? Im averaging 13 -14 in the winter and 17 - 20 in the summer. Hows your coolant level? I run my truck maybe 10 minutes in the mornings, and by the time i drive 6 miles the needle is almost straight up. By the time I get to work, about 13 miles total from home, Im tunring the heat down because its hot in the cab.You should have a block heater on that truck, but it will wonly work when outside temp is 0 or lower. I would insist the dealer at a minimum change the thermostat, you have a 100000 mile warranty on it, use it!

 

[willie in mn]

One more thing, might not apply to diesel/ Allison. Have 97 GMC gas, elec control trans. Puter won't let trans shift to high gear until engine warmed up, supposed to quicken the warm up process. Watched tach, higher rpm at 40 mph cool than at 60 warmed up. Thought trans was failing, but found out it is programmed that way.
HTH
Willie

 

[John M]

I thought about that too, but on mine, its usually through all 6 gears by the time I hit 55 regardless of engine temp, but thats mainly due to the roads I go down before I get to one good stretch of 4 miles. By then, usually, my temp gauge has started moving.

 

[sdc eastern Iowa]

Fluid levels are where they are supposed to be. I plug in anytime it's 10 deg or below or a storm, plugged in last night, scraped what little ice was on the windshield, it takes about 5 min. to get to the main road, and the windshield just started to melt some ice i couldn't reach when I got to work 16 miles away. Friday filled up 27.92 gls drove 263 miles.

 

[Allan in NE]

Winter blend fuel just flat knocks 'em in the head.

Slow to heat is a diesel thing as they gotta work to develop heat.

The colder it is, the longer it's gonna take to come to temp because of the inherent larger quantities of coolant required for diesels.

Allan

 

[Anonymous-0]

My truck wouldn't warm up & had to replace the fan clutch.The other ploblem was that it would want to run warm under load,even when it was 20degrees out.It is a late 2007 with 82000 on it.

 

[Superturbodiesel]

Ahhh, those good "ole emissions controls STRIKE again! Friggen Junk. Long live "global warming"... the biggest farce known to man!

 

[John M]

Hold up, how are you getting that much fuel in the tank? Mine is only a 20 gallon tank. I can squeeze a couple more if Im very low. IF you have used the aftermarket tank, I cant think of the name right off, and are going by the DIC, then you mileage is going to show off. Plus, just looking your fiqureing mileage from how much your putting in it.Your block heater will not come on until its below 0, unless youve installed another one. By chnace do you have this truck chipped?

 

[Matt Weltz]

Winter blend diesel will kill your mileage so expect to loose AT LEAST 3MPG there. These trucks do not need to be plugged in...mine will easily start in -30 degrees. My truck sits outside and I have remote start so will usually let it run for 30 minutes before I leave and I have never seen mileage that low even with all the idling mine does. Have you taken yours down the interstate lately to let the DPF regenerate??? If that is getting plugged up that would drop your mileage pretty quick!

 

[VicS]

My neighbor has a 2010 his mileage is about like yours. I moved about a 05 Dodge the other day and looked up and it's average mileage was 21.4.Don't know if he set me up or not.

 

[mkirsch]

(quoted from post at 16:55:35 02/01/11) Hold up, how are you getting that much fuel in the tank? Mine is only a 20 gallon tank.

What year truck do you have?

Short bed models have a 26-gallon tank. Long bed models have a 34-gallon tank. Standard equipment.

It's been this way since at least 1999. A 34-gallon tank was optional on long beds as far back as 1989.

 

[John M]

2008, short bed, crew cab (4 Full sized doors) Ive never been able to get more trhan 20 gallons in it unless Im very low, as in been driving 2 days with the low fuel light on. Could be that my gauge is off, but I know others with the same truck that are exactly the same. Put 45 bucks worth in it today, 3.19 gallon, right at 14 gallons and gauge hit full, was right ablove the 1/4 tank mark. I may get this looked into now with the info you provided.

 

[mkirsch]

You've definitely got a 26 gallon tank. That should be printed right on the door sticker that came with the truck when you bought it. It's also printed right in the manual.

 

[sdc eastern Iowa]

Ever since it was new you could stuff more than 26 gals. in the tank.

 

[John M]

Its not on the sticker, but the manual does say 26 gallons. I think Im heading to the dealer with this problem, and the other people I know who have the same problem will be going too. Well, one of them, the other is out of warranty.

 

[mkirsch]

Good luck with that... Every fuel gauge I've ever dealt with has its own personality...

The one on my previous truck, a 1997 Chevy with 26 gallon tank, didn't move for the first 80 miles on a full tank. From 80-100 miles, it dropped to 1/4. From 100-200, it dropped steadily to 1/2. From 200-300 miles it dropped from 1/2 to just below 1/4. When the needle said empty, it still had 4 gallons of gas in it.

My current truck is a little less dramatic. It's a 2003 with the 26 gallon tank. The needle drops pretty steadily, getting 80-100 miles per 1/4 tank depending on the time of the year. When the needle is pointing straight at the 1/4 mark, the tank will take 17.1 gallons of gas. That means there's still 8.9 gallons left at "1/4 full." The most I've ever put in is 22.7 gallons, and the needle was down in the red.

 

[Brian Jasper co. Ia]

Are you using a remote start? I have one on my truck and back in the summer I was getting 18-19 mpg.(gas) I checked a couple weeks ago and was down to 12-14 mpg. Remote start is nice, but it does waste fuel. Winter blend diesel has fewer BTU's in it so you use more. The last shift you notice is actually a clutch in the torque converter, not a gear change. Until the trans fluid gets above about 80 degrees, the TCC stays off. Then there's the DPF in the exahust. Cold engines produce more soot and if you are using the truck like a car, it will go into active regeneration more often.

 

[john_Bud]

It takes almost as much fuel to idle when it's near zero as it does to drive on the freeway when warmed up. Huge waste of fuel just to feel warm and toasty. I don't do it, park outside, don't use a plug in heater either. Starts grumpy at -20F,but starts.

You NEED both parts of the front end cover. BOTH the center grill cover and the larger bumper cover to keep the engine heat in.

You should also make sure that the truck has synthetic fluid in the differentials, transmission and engine oil. It will make a big difference.

Have you made sure the tires are pumped up? Low air pressure will also suck more fuel.

Have you put larger tires on? The electronics are tuned for the stock tire and upsetting them with larger tires seems to make it suck more fuel.

Last, driving style makes a huge difference. Lighten up the foot for better economy.

 

[Stuart]

How do you know it takes the same amount of fuel?
Seriously you start it up, not plugged in and you dont let the engine warm up for say 5-10 minutes? How much fuel can it burn in that time? Maybe a quart? even less?