Fifth Ring

I can't say enough good stuff about the GL320. I drove for 6 hours and felt zero fatigue. We were cruising up and down "mini-mountains" in Southwestern Pennsylvania, and the GL showed no signs of strain regardless of the speed or incline. I was also impressed at how the GL uses engine compression to keep speeds DOWN when on cruise control headed downhill.

Even averaging 70MPH in this terrain, we showed an average of 25MPG. And if we were willing to drop 5 or 10 MPH, we would have done even better. I thought that after a lengthy drive we would at least have a smudge of soot on the back bumper, but it's cleaner than my gasoline cars.

It's going to be interesting to see how big SUVs evolve. Hybrids can match the efficiency of diesel, but have longer term issues (resale, battery life). Clearly the US makers have bet on hybrids (which is easier than developing diesel powertrains). And Euros are relying on diesel.

lkchris

I think it's actually using brakes. Easier to check at night when you can see the lights.

Hybrids are city cars, i.e. it isn't the electric motor making the car go 70mph on long drives.

I rather hate to think of a GL as a city car and I agree about the highway capabilities as I just did a couple of 12-hour days last weekend--Albuquerque--Tulsa--Albuquerque. Had westerly winds both directions, so 27 eastbound, 23 westbound.

Not very good for my DVT problem, I suppose.

Fifth Ring

If it's using the brakes, that's WAY cool. I'm impressed all over again.

We still get 18 MPG in "city" use (basically school bus and soccer practice trips), which is very solid.

Overall, the GL320 gets better fuel mileage in EVERY situation than my little C32!

lkchris

Recently at my dealer they had new C350 and an '08 GL320CDI on the floor next to each other.

EPA ratings for C-class were 17 city, 25 highway

EPA ratings for the GL were 18 city, 24 highway

VERY impressive for such a much bigger, more capable vehicle.

Fifth Ring

"Real world" mileage for my C32 is probably 17 city, 22 highway. Pitiful. (But fast!)

StevethePilot

+1, if you're covering the brake when you slow the cruise control by 5MPH (past the detent), you can feel the brake being depressed. Not that engine braking would be that bad, especially coming in to Verde Valley from the south, but the braking action is fairly smooth and effective.

I first noticed it a number of years ago on a rented (yes, rented) SLK I took up to Sedona with my wife for our anniversary. Just a really nice idea that shows some thought on the part of the engineers.

STP

gordongl450

I had the same nice experience. Did a 750 mile (total) beach trip with our ML320. Ran great on the highway. Average mileage was 25.5 mpg for the complete trip and that was loaded with luggage with a lot of 70 mph driving.

Couldn't be happier, the diesel is great!

Gordon

Danno4x4

+2 on the Cruise Control Braking function... I had noticed this not long after I got the vehicle, but I wasn't sure if when it applied the brake during cruise control if it also activated the brake lights... It does... I was able to see the brake lights reflect clearly off of the trailer I was towing at night...

I think this is a great function, but I was concerned just a little bit when towing a heavy trailer... Whenever the vehicle brakes are activated during cruise control, it also activates the trailer brakes (generally a good thing). But on steep long descents, I felt that activating the brakes lightly for longer durations was actually not good for the trailer's brakes... I could smell them heat up significantly when I stopped at the bottom. Based on this, when descending with a trailer, I would rather let the compression braking do its job by selecting a lower gear and then use the brakes a bit more aggressively, but in shorter durations to slow the vehicle down.

FrankW

so how much are you paying per gallon on diesel?

below is a little calculation when I saw the 320 CDI's estimated fuel cost.

$3375 ($4.50 per gallon) annual fuel cost. the ML350's annual fuel cost given MB uses $3.00 per gallon for unleaded is only $2646 with a combined mpg rating of 17mpg. Hell, even if you only get 15mpg from the ML350 your annual fuel estimate is still $375 cheaper than the BlueTec. You are paying $375 to $729 more on fuel with the BlueTec to travel the same distance 15000 miles.

also with the way they calculated the cost using 20mpg it means that the gas tank is indeed 20 gallon which makes the cruising range only 400 miles per tank for the BlueTec not 600. If you want to get 600miles out of it you'll need to avg 30mpg which is highly unlikely.

haven't pay attention to recent price of the diesel tho.

oh yea, I get 25+ mpg on the highway with the C350 btw and can get 23-24mpg on the C32 on the highway as well. combined the C350 is usually 20mpg vs 17mpg for C32.

scottybdiving

I paid 2.94 for diesel yesterday. Our GL 320 averages 22+ for everyday driving. My C3500 Duramax gets 15. That is calculated the old fashion way, not by the computer. Many of the people here are reporting even better numbers.

FrankW

what about the 91oct or the highest unleaded price? have to check how much is the diesel in my area, but the 91 is $2.95 right now. the diesel i remember is usually .50 more or more. just doing some calculation for the heck of it since parents will be looking soon.

TV550

Those estimates are based on this website: www.fueleconomy.gov just plug in your driving style and the cars you want to compare whether disel or gas and it will give you an accurate estimate of how much disels save you money even if its 50 cents higher.

scottybdiving

Diesel runs about 6-8% (summer) and 15-20% (winter) higher than Premium around here. That seems to vary widely across the country, depending on climate, additives, and demand for heating oil.

StevethePilot

Experience towing lets you be able to create this type of strategy. I think the GL doesn't have this internally because there's no brake controller MB makes and tests with the towing ability. I agree that to a certain extent the engine braking is fine, but let's not forget how tiny the engine is! There's only so much it can do.

robalo220

also with the way they calculated the cost using 20mpg it means that the gas tank is indeed 20 gallon which makes the cruising range only 400 miles per tank for the BlueTec not 600. If you want to get 600miles out of it you'll need to avg 30mpg which is highly unlikely.




I had an 07 ML 320 CDI and it had a 25 gallon fuel tank. Highway milage I could get 29 mpg and over 700 miles per tank. Around town, I averaged 23 mpg and would get over 500 miles/tank. I do not know if the Bluetec changed the tank in the ML. My 08 GL 320 CDI only has 4000 miles so far and I have averaged 25mpg over the road and 19 around town. I prefer the torque of the diesel for trailer towing. Does really well. The GL has a 27 gallon tank. In town driving I go 3 wks between fillups. Beats stopping once per week with the gas version. Only my humble opinion.

robalo220

Sorry FrankW, I didn't get your quote to show up as a quote above.