newyorktoLA

Today, I averaged 15.7 mpg with my GL350 during mixed city/highway driving on a 70 mile trip. Is this normal? Whenever I fill up now, my range is only 400 and something miles, not 600 like it was before. If there is anything wrong, what should I do to fix it???

Thanks in advanced.

dbtk

Get 23.5 on mixed driving.

43221B

That seems low under any circumstance other than towing. Take it to the dealership and have them diagnose it.

alx

yes. this is very low.

you should be averaging about 20 in mixed normal driving.

25-27 is the norm for highway and 17-20 for strictly city traffic

at least that is my experience

Brocktoon

Lots of stop & go, idling and heavy A/C use can pull your average down substantially. Don't forget it is a distance/consumption equation, so every moment stopped adds consumption without distance. So, even over 70 miles, it might be hard to make up for 10 minutes of idling or stuck in traffic, by the computers reckoning.

Any of this apply?

jimmyp

I get around 19.5-20.5 city and 25.5 highway with 1200miles on my new truck.

ksalno

I was just scrolling through my mileage calculations and am averaging just under 20 mpg over the 2800 miles of mixed miles I have on my GL350.

fs1013

I am traveling and can't verify to the car. But that sounds right from memory.

Mine is now just over 5000 miles and mostly city. I gave it a test for highway a couple weeks ago on a trip of 65 miles. Reset it when I got on highway and read as soon as I got off. I set the cruise at 65 mph (with Distronic). The reading was just over 30mpg and that included 15 minutes bumper to bumper through the city.

lkchris

Did EPA figures change between 2009 and 2010?

Between GL320 and GL350 that is?

If it makes more power it takes more fuel to do it.

43221B

Funny you should bring this up. There has been a lot made of the few (2 I think) pound feet of torque increase of the 10 over the 09 but I have never heard of an engineering explanation of where they are getting the extra torque. Interestingly, in my 09 manual, it lists the torque specs for the 320 at 400 lb ft, same as the 350. On the window sticker, it was listed as 398 lb ft. Makes me wonder if there was a typo in the 09 manual or if there really was a change between the years. I have heard that some manufacturers don't always include all the power in their specs particularly when an engine is used across multiple models.

BTW no, the EPA numbers didn't change. I'm not sure if 2 lb/ft of torque would change the numbers though. 2 lb/ft is what, a .5% increase?

Fourdiesel

Just because an engine CAN make more power [torque] doesn't mean it does in actual use. The fuel to create 100 lb-ft of torque is the same regardless of engine (as long as the engines are the same basic design - pistons, bore, etc and the same order of magnitude in general torque / horsepower peak output). Small differences in rated peak output will have no effect on the fuel consumption at fractional output. There are undoubtedly differences in the 320 vs the 350 efficiency due to different fuel maps because less egr recirculation is necessary on the 350 due to the availability of BluTec fluid to control NOx.

43221B

I agree with you but do you have any insight on the difference between the 2009 320 Bluetec and the 2010 350 Bluetec? I'm sort of sceptical of there being any real difference.

Fourdiesel

I don't have any direct knowledge of the differences. Even the emission requirements differences are minimal. If I had to guess I'd say the difference is 30. 350-320=30!

rich4368

I had that problem with my 2010 GL350. My GL350 was getting about 16 mpg in 30-40 mph driving with range of 5-10 miles and 19-20 mpg on highways. I brought my truck in three times for dianostics but nothing found until CEL came on on my third trip to dealer and they finally diagnosed the faulty adblue pump and had that replaced. That was 2 months ago with 7,000 miles. Now I am closer to 10,000 miles and mpg has been great. Did a round trip from Bay Area to San Luis Obispo averaging 25-26 mpg the whole trip with AC running half the time. In city driving I am getting 22-23 mpg. Check out the previous link: https://mbworld.org/forums/gl-class-...ine-light.html

DucatiNut

Always get around 21 around town. If I drive it very carefully I have seen 35 on a 350 mile trip! Your mileage is WAY low.

StevethePilot

35mpg over an entire 350 mile trip? That has to have been in absolutely ideal conditions. Loaded with four people, two small dogs and all our clothes/etc. for a long weekend, and with crosswinds the whole time, I got around 22mpg average at freeway speeds (I-10 in to about Los Angeles, fairly flat). If you're doing actual calculations (and not relying on the trip computer) that show 35mpg average over an entire 350 mile trip and not just one section or something, I'm very impressed. And a little confused.

dbtk

Just got back from a 2,900 mile trip back and forth to Disney World from Connecticut. 27.9 mpg averaging 70-75 mph on the freeway, A/C on, and several rain storms on the way back up.

43221B

The diesel is pretty incredible on those long trips. How many miles were you going between fillups?

dbtk

As few as 300 miles and as many as 500 miles. I was trying to optimize tank fill-ups and the price of fuel. In some cases through VA and NC, I found diesel for as low as $2.699 per gallon (a far cry from $3.519 in CT).

HamMan

My best mpg in a 2009 320

StevethePilot

I'm not impressed with the onboard computer. This is my best mileage, based on my 2007 320's computer! I'm afraid manual calculations are the only reliable way to know real mileage, or at least a more reliable way.

43221B

The diesel runs one gear lower that it needs to at speeds between about 25 and 45 mph. Only when gently accelerating for quite some time will it "learn" to run in a higher gear at those speeds. So, if you want even better mileage, use your right paddle to shift up a gear at speeds below 45. This has been discussed before but I think it is worth repeating for new 350 owners.

Fourdiesel

I hope the '09-'10s have a better response to the shift paddles than my '08 does. I have tried and tried to get my '08 to upshift at 25-40 mph - 1400-2100 rpm, going slightly downhill, small added throttle (or none) and I have concluded my tranny is dyslexic! NO upshift - ever - until a full 30 seconds has past or I get to 50 mph. To me, the paddles are almost useless. Click once on the left paddle (even by mistake when turning a corner) and you get the LOWSET gear possible rather than the next gear down. On upshift with the right paddle you sometimes get one gear at a time but other times it jumps all the way to drive. I never can tell when this is going to happen.
I would also like to see the actual gear it is in displayed (where P/N/D show) rather than just the D all the time.

StevethePilot

WEIRD! On my wheel, the paddles are rockers and the outside of the buttons is up-shift, the inside is down shift. That helps avoid the "mistake" button press. I wonder if that's a Startek thing or something unique to the wood/leather wheel I replaced my OEM with?

Fourdiesel

On mine (stock m-b text wheel w/ heat) the switches are rockers but are only momentary contact single throw - ie 'on' or 'off'. Left side for downshift, right side for upshift (but only when all other parameters are satisfied, including pissing me off!)