need help w/08 dmax

[tim444]

I am a first time diesel owner, I have a 08 2500hd with the 6.6 duramax I am not sure what some of the lingo on the site means I would like to know how to figure out what version of what motor I have. I also was wondering if anyone could tell me what kind of mileage they are getting out of the 08's because I am only getting10-12 and thought it would be much better. The truck only has 6600 miles on it and people keep telling me to let it break in before I worry about it. How long does it take to break in? And lastly if there are any other Illinois duramax owners Have you had the trouble with the biodiesel blend this winter

[DmaxMaverick]

Your engine series is "LMM".

Mileage is rather subjective. They do improve with some driving time. Much of your mileage, now and later, is dependent on the type of driving you do, and the weight/drag of your rig (including the load and/or trailer). The LMM's are a bit more thirsty than previous models. This is due to additional fuel used for the DPF (Diesel exhaust Particulate Filter) regeneration (cleaning process). Different types of driving will effect this greatly. If you are driving mostly in city traffic, with lots of slow(er) stop and go, it will require more often regen's, and they will take longer than if running on the open highway (more fuel). Beginning in January, 2007, all on-highway Diesel vehicles were delivered with this exhaust system. There are ways to defeat this feature (for test-track use only, of course, as tampering is unlawful). Your best bet is to spend some time reading up in this forum (the Duramax Forum) and become more familiar with what you have. Of course, we are always here to answer your questions, so don't hesitate to clear any confusion.

Good luck, and welcome aboard!

[EdSpaek]

I live in Illinois and now have 23,000 miles on my 08 2500HD with Duramax LMM

My mileage is between 17 and 22 and has been that way since 3000 miles were on the truck.

I would not recommend Bio Diesel in the winter, we have 15 of these vehicles in our fleet and keeping them moving when below zero has been a challenge between clogged fuel filters, poor quality ULSD fuel and the needed additives to maintain the flow point of the fuel.

[Runaway_Dmax]

Mileage is all over the board with the LMMs. Mine avgs anywhere from 17s in the winter to high 19s in summer. As mentioned stop and go will kill the mileage on the LMMs because of the mandated emissions. I never use my truck for city driving, it was bought to pull the camper and boat and whatever else I decide to haul. If the mileage you posted is city driving, that seems to be the norm for what I have seen others post and complain about.

As far as the Illinois bio blends, there has been considerable discussions about this on other DMax sites and conclusions have been drawn that in Illinois the fuel is blended with Bio-Diesel to B11 which is 6% over what GM allows. Folks are having big issues keeping there fuel flowing with that Bio blend. Winter Front seems to help, but not the holy grail.

[MacDR50]

I am getting 10-12 MPG (imperial) or an avg of 22 liters for every 100kms. My unit has only 1100 miles and its all stop and go city driving. I take it out for a 30 minute run once a week just to get the DPF regeneration done. With diesel now about 18 cents more a liter than gas I wish I could have bought an 8.1 but, alas, not available.

[afp2007]

I am getting 10-12 MPG (imperial) or an avg of 22 liters for every 100kms.

we have about 39,000 km on our 2007 DMax and recently got as much as 22 imperial mpg on a longer highway trip. Around town, with stop and go, significantly less. I suspect you mileage will improve, but certainly city driving is not economical driving

[MacDR50]

Wow. That does make me feel better as, once the summer gets here, I expect some longer highway trips.

[lmholmes11]

My father in law just got an 08' and he is averaging 12-14 mpg city, maybe 1 or 2 mpg more on the highway. When he is towing his tandem axle snowmobile trailer fully loaded he gets down around the 8 mpg range. So don't feel bad about your low millage!

[tim444]

Thanks for helping clear up the around town mileage issues everyone. It's nice to know I am not the only one suffering.