I had a 2004 diesel Excursion 4X4. It had the 6.0L. I loved that car. But I did the stupid thing of putting a 6 inch lift on it. It made my gas mileage drop to around 8 mpg! I agree though, that thing would tow ANYTHING! You couldn't even tell our boat was behind us. I got tired of driving such a big truck. I had no problem getting high book for it when I sold it last year. I have yet to tow with the GL yet. My boat is pretty heavy but well within the specs of what the GL can tow.

My cdi has 3500 miles and I am averaging 23.2 since new. Last tank was 24.9 average. 3/4 highway 1/4 city.

My 320 CDI has about 2K miles on it and I'm getting about 19 MPG overall, with about 3/4+ city driving. I was getting about 17 MPG earlier in the winter, but it has been improving. On the highway, the trip computer says I'm getting in the 23-24 range, but I've yet to log any serious highway miles.

I fondly remember the $3.34/gallon that diesel was selling at back in February when I bought the GL.

My 550 is at 16.2 mpg for 5300 miles with an average speed of 29 mph. City 75% and highway 25%.

Great info here. Looking to get a 550 as a gift for a close friend. Love the styling (though I would prefer the rear bucket seat option of GM), but GL drives much smaller than the vehicle actually is. Comparing Cadillac Escalade Hybrid (due soon), Enclave and Aspen (the latter because of the $2.99 per gallon gas lock offer Chrysler's having). However, I do want the Tele-Aid or OnStar option, only offered on the former two.

Another insightful tidbit here:

https://mbworld.org/forums/showpost....17&postcount=9

For what its worth, I have found that when I do a manual calculation of fuel mileage (i.e. fuel the vehicle at the same pump and stop fueling after two clicks of the nozzle.) the computer is actually under estimating the fuel mileage, sometimes by as much as 2 MPG...

I don't know why it does this, perhaps the mileage calculator is based on some algorithm for an average GL 320 and using all of the sensors to estimate.

I suggest you do a few manual calculations and see if yours does the same. It would be interesting to see if the 450 and 550 are the same or more accurate, or ever perhaps if they are over estimating the actual mileage.

With my 320 CDI I am getting 22.5 driving very conservative and am at 24.5 on the highway, if I drive at about 60-62...This keeps the engine at about 2000 rpm which seems to be an efficient spot for it...

Diesel is $4.55 in Dallas and going up by the day

I hear you Danno.

I don't remember how much mine was off last fall, but the computer was always underestimating based on my actual calcs. So, I don't even pay attention to the computer anymore.

$4.99 in southern California.

$5.06 in Southern NJ.

$4.34 in Austin, TX. on Wed.

3.95 this morning in NJ. Not bad at all

I get 13.8mpg. Knew what I was getting into when I bought it.

Full tank of gas=$80

Sh*t eating grin when I floor it = Priceless

Diesel is $4.56 in Southern NJ.

I had an interesting experience on my trip to Arkansas last week. The trip down to AR returned an expected 24+ mpg with avg speed of 70 mph. I filled the tank at a Valero station in Little Rock and immediately saw a 10% to 15% reduction in fuel economy. This continued throughout my stay and on my return trip back north through AR and MO. I filled up my nearly empty tank at a station on the MO/IL border and saw my highway fuel economy immediatley jump from 21.2 to 24.5. Same speeds and same wind conditions as the AR and MO portions of the trip. Just different fuel.

What gives? Did Valero slip some Diesel #1 (kerosene) into the Diesel #2 pump? The GL ran fine. It just returned lousy fuel economy with the Valero diesel fuel.

While they might not have an answer (and it may be questionable if they even give you one), it might be worth reporting that to MBUSA and asking them why there'd be a difference with diesel pumped out of the ground by a ruthless nationalist socialist dictator?

STP

PS Not that I have an opinion, just pointing out facts.

Did the elevation change substantially to your destination and back?

Apart from any ultra low sulpher mixup, I've often wondered if there are differences in octane levels in diesel fuel from manufacturer to manufacturer. Gasoline purchasers always get several octane options at the pump, we only get one. Is it possible some refiners produce higher octane diesel? Unfortunately, I don't know enough about diesel to know whether an "octane" type rating even applies. Perhaps one of our more knowledgeable forum members can shed some light?

Quoting another website entirely;

Hope that helps.

I thought Valero was a U.S. company?

I never buy from Citgo due to its Venezuelan (i.e. Chavez) ownership, but I'm not aware of any similar associations with Valero.

... oops ...

See what happens when you become reactionary? <Sheepish> Valero's out of San Antonio. </Sheepish>

STP

I'm thinking of purchasing a GL320 and had one out for a couple of hours today. I reset the computer and after an hour of city driving, it showed 23MPG (Canadian Gal., or 19.28 US mpg). If showed 30 mpg (Canadian Gal)/ 25 US mpg.

I was driving the speed limit (30 - 40 mph in town, 60 on the highway). I was trying to take it easy (i.e. no flooring it off the line, etc.) I expect it would do a bit better once broken in.

Interesting, thanks.