jongaines

Raleigh to Asheville, NC (about 235 miles). Averaged 24.6 miles per gal of deisel with 6 onboard with full luggage (not even and inch of room left; could not see out the back window). The sweet spot on miles per gal seems to be at about 65 MPH; I averaged close to 80 which probably hurt the mileage a bit. I am probably going to need a roof carrier if I am going to load up like this again. I used just over 1/4 tank of deisel.

blittle

Wow....! Great mileage.......of course I have the gas 450 and 19.8 is the best I have done

N'AWLINS

I'm off today for a 600 mile trip to the Big Easy...I'll let you know how I do with MPG. I'm taking some back roads, so may not get optimum MPG. Hope I don't have trouble finding Ultra Low Diesel on the back roads.

jongaines

The range is the best part.

HoustonRider

I get about the same mileage with the truck almost empty running 70-75mph. On a full tank I'll still average 20+mpg (over the 26 gallons I burn per tank). Tank average is the deciding factor on what your mileage really is.

the trick is to get cruising 70 mph, then zero out your trip computer.. depending on terrain, you may or may not get better mileage. I've seen 26mpg... low wind, flat (I'm a sea level) and no traffic interruptions (cars in way, stops, etc...

HoustonRider

you should be able to do your who trip on that one full tank (provided you fill up before you leave).

Im in South Texas and ULSD is pretty hard to find in ALOT of areas around here.. If you stop and see ULSD I would top off, just in case. I found myself scrambling for ULSD a month ago, and with this kinda range, I'm not chancing it.

No Valero Chains sell Ultra Low. Neither do most Citgos in my area. Exxon and Chevron sell it pretty consistantly.... I can't find it at Shell either.

good luck !

StevethePilot

It's a shame to say it but you're going to miss out on some of your best ULSD deals by leaving the major highways. I found deisel below $2/gal the summer before last on I-80 several times. Off I-80 prices at the time averaged around $2.60/$2.70, so that's saying something. (Of course, you also want to be sure you're not filling up at the trucker pumps in case they're tax-exempt or you'll get a lesson in gas taxes!)

STP

N'AWLINS

An update....travelled back roads of Florida along the west Gulf Coast and now along the panhandle coast. You all are right ULSD is very difficult to find along the back roads!! Thank goodness I filled up in Orlando.
Have travelled about 350 miles and averaged over 23mpg....lots of little towns, lots of accel and deccel.....and tank is only half empty!! Man, I'm loving this!!
May be wishful thinking Steve and Nevada, but I believe my abrupt downshift is smoothing out......more to come.

NbyNW

We drive very little... 1900 miles since September so the engine is nowhere near being broken in. I've only checked mileage a couple times. 17 around town. 24 going ~73mph and 25 at a more relaxed 60 (lots of police on back roads). We're happy. Just wish diesel was cheaper.

I thought ULSD was all that was made now for highway use. Guess I thought wrong.

NbyNW

During our last drive we got the "check oil level at next fill up" message - twice while driving. On a couple other trips got the same message. The level was ok but I added half a quart anyway (still in the normal range). Seemed to fix it for a month. Guess it wants more. Until everything seats properly better keep oil handy, especially for those on long trips.

alx

just a little dirty secret.

our trucks dont have the urea filters (that is why they are not officially called bluetek albeit everything else being bluetek-identical).

as such, we dont really require ulsd. said that - carry some stanadyne additive with you and when in a pinch- fill up with whatever diesel you can find and mix it up per directions with the stanadyne... dont make it a habit, but sure beats running out of fuel in the middle of nowhere.

my 2 cents

alex
few cars

lkchris

Not correct.

ALL 2007-on diesels--any make--require ULSD. This has NO RELATIONSHIP WHATSOVER to urea systems. It's the particulate filter, and if you damage yours it won't be covered under warranty. You can also damage this filter using non-229.51 motor oil (any quantity).

alx

technically correct. however, here is another little dirty secret (i assume you dont own any gas stations- do you)... - LSD and ULSD diesel fuel is added as the batches arrive at the distribution depots in the same tanks- where it is pumped into the trucks that deliver it to gas stations. so your ulsd is never ulsd but an indeterminable mix of ulsd and lsd.

so while technically you are correct, i can guarantee you that it really makes no difference. the only difference is that when you are running on lsd fuel more smoke might be visible at wot as the particulate filter is letting through more soot (which you can keep down very successfully with stanadyne btw).

regarding the oil- dont even start me on it- vw has the same nonsense with the PD-engines requiring 505.01 oil which has been proven to be superficial as lots of people run 0w40 mobil 1 with great success. a dead give away is also their requirement for the old audi rs6 to use the same oil... and the rs6 is just another twin turbo low-boost application which is happy with any good full synthetic oil.

alex
few cars

gordongl450

My wife an I drove about 120 miles to pick family up from an airport for the holidays. Using the 2008 GL320, not broken in yet with only 500 miles on it. Almost all interstate highway driving at 70 mph. Picked up two adults and 3 bags, a guess about 400 pounds total.

Driving to the airport I was getting 22.8 mpg. After picking up the family and the luggage and driving the same route home the mileage dropped 21.8 mpg.

The next weekend doing the opposite, bringing the entire family and luggage to the airport and then driving back home 400 pounds lighter the mileage numbers were about the same for the two trips.

So, I thought it was interesting how the load weight affected the mileage. I also thought it was interesting how sensitive and "I guess accurate" the GL computer was.

StevethePilot

Alx, I hate doing this in text because it'll sound like I'm being a jerk and challenging you but I'm really being sincere in this questioning; can you please tell us where your information on LSD/ULSD and engine oil comes from? You see, when I spend ~$60,000 on a vehicle and they tell me they won't warranty the engine unless I use ULSD (which is a great deal lower in sulpher than LSD) because of filters and injectors and so forth, I tend to take their word for it. The same's true with the oil. From what I understand, the only difference in bluetec will be emissions and not mileage, so these are very different engines from your average CDI. So please let me know, what is your source of information?

Thanks,

STP

gordongl450

Steve,

I kind of agree with you on this. I figure the guys at MB know best what is best for the long term wear and tear on the car. I don't intend to try fuel or oil that is not recommended, why risk it: to save a few cents when buying a 65k truck?

It also reminds me of the long threads about sitting in the GL320 for a few minutes to let it warm up before you drive off. It sound like a reasonable idea. But the MB manual does say you have to spend minutes at idle waiting for the engine to warm up. If this was necessary I think it would be in the operating instructions. Having said that, in all my cars, on cold days, I would give them at least a minute of idle before going into gear and driving.

My 2 cents.

gordongl450

Mistake in my post above.

The MB manual for the CDI engine does NOT indicate that any extra minutes warming the engine, after starting, is necessary before driving off. It does state in the fuel economy section of the manual that warming the engine will improve fuel econmony.

In fact, it refers to the Preglow Indicator in a couple of places. It basically states that "if the engine is at operating temperature, the preglow indicator lamp may not stay on and you can start the engine without preglowing."

So, "operating temperature" seems to be when the cylinders are warm enough to start, with or without the need to preglow. So, if the engine is warm enough to start, I guess it's warm enough to put in gear and drive?

tm4exc

My experience (after 2470 miles) is that wind resistance tends to affect mileage more than load in this truck unless the terrain is really hilly more one direction than from the return trip. This is why MB spends so much engineering on reducing Cd and frontal area(lowering drag coefficient). Going north to Oakhurst I averaged 17.8 fighting a head wind for half the trip. Coming home averaged 19.8 averaging 3MPH more for the entire trip.

gordongl450

tm4exc,

You make a very good point and interesting observation, thanks.

Do you agree that the mileage or in the GL is a very cool thing and relatively accurate?

Gordon

tm4exc

Sorry for late response. have been puppy training!
I have checked clocked consumption against the fill-up (<1% difference) and find that number very close to the accuracy of the speedometer which on my clock I have measured as 98.6% of indicated. We have two of those " you are going this fast" radar signs on highway 154 and both of them read me 1 MPH slower than is indicated on the digital speedometer. Of course the radar gun(s) or signs are probably no more accurate, so there you have it. The clock and digital readouts are close enough for me to trust them you might say!