rr7775

What would be the effects of using regular unleaded fuel on a GL450 as opposed to "premium". Say 87 instead of 91 or 93. Any real issues?

AsianML

Yes, in the long run. There are a number of threads on the subject.

GGM

The percent difference in price between regular and premium goes down as the price goes up. Right now with regular gas at about $3.15, that difference is about 6%. When gas was $2.00 a gallon, the difference was 10%. If you look at it like this, premium doesn't seem so expensive. I am pretty sure that you will get more than a 6% loss in gas mileage by using regular instead of premium.

For the life of me, I can't understand why someone would spend the money for a Mercedes and then cheap out on the gasoline. I only run Chevron premium in my car. Both the previous C240 and the present E350 run much better on Chevron premium. I am averaging 21 mpg with mostly short trips to work (3 miles) and longer trips on weekends.

I also found that using the recommended midgrade in the wife's Chrysler 300 yields better gas mileage by a greater percent than the price differential. The manufacturers make no money from your use of premium.

You may want to search the forums before you post. There have been many threads about this. Other members may not be as kind when you don't search to see if your question has been answered before. I am speaking from newbie experience.

cablvr

I'm not a chem eng - but I think the octane differences will have an impact on engine performance. I'd be reluctant to risk a $20K engine on a $240/year savings in the cost of fuel. IIRC, you also void your warranty.

lkchris

I always like to invite those contravening factory recommendations to put their money where there mouth is by posting their VIN number ... so the rest of us can avoid their vehicle when it comes on the used market.

cablvr

StevethePilot

What about the effects of B99/B100 on the CDI engine? Mercedes says they approve the B5 (5% biodiesel) product but at that concentration it's really not efficent.

Of course the other freaky part is that the vegetable oil's currently more expensive than the diesel fuel (insane, party of 1?) and I don't think it carries exactly the same energy/weight ratio that petroleum diesel does (i.e. slightly lower mileage) so that doesn't add any incentive to the equation. I just think it'd be kind of cool to drive around on the stuff.

STP

dunderhi

MBUSA recommendations, not the factory. When I did my Euro Delivery on the SL, the car was programmed by the factory to run on regular through premium grades of gas. When it was shipped to the US, it was reprogrammed at the VPC to run on premium only.

dunderhi

I've been running my New Holland Tractor on B100 during the non-winter months for 5 years now. The tractor runs smoother and quieter with B100. B100 does gel more easily, so I don't use it in the winter. BTW, New Holland only approves of B5. As a word of warning, never introduce anything greater B5 than into an older vehicle. It will disolve all of the crud in your fuel system and clog your injectors.

lkchris

The "what about it" is that it voids your warranty.

Injectors are about $800 each and the fuel pump approaches $2K.

Are you feeling lucky?

StevethePilot

Kent, you're such a pragmatist! Of course I'm not going to run it in the truck, especially with the teensy injectors the ULSD allows. They'd clog awfully quickly on the smallest bit of crap. It wouldn't probably affect the pump at such a young age (though older cars certainly could) and filters could be put in place but there could still be buildup downstream of the filters that they'd miss, so it's not worth it.

Now, if I had an old turbo diesel wagon ... I just might!

oinick

My GL 320 hasn't run worth a damn since I started using 89 octane. I may have to go back to 40 cetane. All those "-anes" sure do confuse a southern boy. Cows make a lot of methane, but that won't work either.