03 ML500 poor gas mileage
 

Hi ,
I recently purchased a 03 ML 500 with 69k. The gas mileage seems to be very poor. I get about 9-10 mpg. What should I fix to improve the mileage other than replacing the plugs. BTW it has 16 plugs. Thanks

smk_texas
03 ML500
98 S420

You are probably real close to "real" numbers. The 03 had a combined MPG of 13 add some Air Conditioning and 10 is the mileage I see.

Thanks very much. I thought it would be low around 14-15 but I was surprised when I was getting only 10mpg. However, I enjoy the performance of this vehicle.

smk_texas.

Plug change interval is 100K miles.

Thanks Kent. Do you know if it takes synthetic or 20w50 ??

Spark plug chang should be 5 YEARS or 100K wich ever comes FIRST.

And 100K miles does damage to wires & coils. ON the latest schedules MB recommends 78K for spark plugs.

I get 12-14 in town, high teens to almost 20 on a trip. To hit 20, I need to keep it under 70. Problem in part is MB chose the wrong diff gearing for the V8.

Suggest plugs every 50k, they will last longer but they do wear out.

I have switched to M1 0w-40, seems to help slightly on mileage, but I do it mostly for wear characteristics of M1. Oil change now in the 7500-8000 mile range.

Regards,
Jerry

I am fixing to change plugs in my 03 ML500. Should I use the bosch platinum +4 or the regular bosch F8DPP33 (see attachment) . Please advise. Thanks.

smk_texas
03 ML500 70K
98 S420 71K

Good question,I was looking to replace plugs also. I don't know the answer, hopefully someone who does will chime in.

******** lists 3 plugs:

4501
Bosch
Spark Plug; IR Fusion+4; Iridium/Platinum with Four Electrode
16 per engine Patented fused iridium and platinum center electrode for better than OE Iridium performance. $20.20 $6.52


4418
Bosch
Spark Plug; Platinum+4; 4 Electrode
16 per engine Pregapped for normal usage. Not recommended for supercharged or turbo models. $13.80 $4.86


7422
Bosch
Spark Plug; Platinum; Standard Electrode; OE Plug
16 per engine Updated version of OE spark plugs F8DPER and F8DPP33. Pregapped for normal usage. $17.95 $4.37

7422 seems to be "OEM'.



Does anyone know what would be one heat range colder? For example would a 4417 be one heat range colder or hotter than a 4418?



Regards,
Jerry

I have a 2003 ML500 with 105k on it now, purchased it used with 60k on it two years ago.

I have been consistently getting 16 mpg around town and 20 mpg on the highway. In the winter, its much worse - 13/17 or so. Mileage depends more on temperature than any other car I've owned.

I replaced my spark plugs at 85k miles or so. Had the dealer do it. I also change the air filter about every 15k miles. Mobil 1 synthetic - 5w-40 I think - I buy it at the dealer for less than $6 per qt.

The key to good fuel mileage on the hwy is to use the cruise control. I've even observed 21 mpg driving at 85 mph across Indiana at night with the cruise control on, AC off, in 60F weather.

Considering I would get maybe 23-25 mpg in the old 617 diesels I've owned, the fuel mileage of this ML500 isn't too hateful at all.

CB

That is excellent mileage. I have the AMG wheels and 255-55/18's, which don't help mileage, but since my last post, I changed the ring and pinion in both diffs (not cheap) for better mileage and less wear and tear on the motor.

I now can get 21-22 mpg (measured) cruising around 75. Computer reads about 5% low, so I am getting better than what it shows. That is within shouting distance of a diesel.

Car is very enjoyable on the highway now, since revs are also reduced about 500 rpm at cruising speeds.

Regards,
Jerry