Car Forum World

No I would not propose it.you may damage then engine by doing so.but no I would not propose putting regular in a S420.

Unleaded premium is suggested only.

I could verify with the owner's manual on this one. Most cars run proficiently with regular unleaded, as it was proven thru buyer reports that the grade of gas is not really important, unless of course it is a high performance car. Some European models although, are DIESAL only and putting regular gasoline in it'll damage it.

Nope gotta put premium in it. usually it depends on what went into the tank when it was 1st bought. If cost is the issue you may be able to purchase octane increase at most any auto parts store or gas station.

you can put regular in it, but do not expect as good of performance, though you'll save money.

Your car has a knock sensor on it that can give a false reading if you use regular gas. You may not notice it at 1st but over time it may because more problems. The sensor is to keep the car from misfire firing and low octane fuel burns slower so the sensor may attempt to up the amount of fuel or change the spark time to correct it.
If it adds more fuel you will end up burning the catalytic changes out and that's costly to replace.

Not a smart idea. you may be able to use regular in an emergency, but do not drive with a heavy foot while regular is in the tank. you may be able to do bad things to your valves and head gasket with low octane fuel.

unleaded only

yes and no, Yes only if there's no premium gasoline available, then you may add a mixture of regular gas in addtion to the premium requried. No as indicated by Mercedes Benz, they don't recommend running any mercedes benz under regular gas, caused by the low octane in regular gas, mercedes engines are complex and require a lot of energy to run, premium gas 92 octane . They say if there's no premium gas then you may add a little to the gas tank.

Mercedes are premium only why, could you do that?

What does it say on your fuel gauge, or inside the gas door?

If it says PREMIUM UNLEADED ONLY.

You can, but you'll regret this tremendously.

Dont listen to these people. I drive a lexus lx470 with a alike engine size and I use regular in spite of its demand for premium. My car now has 150,000 miles on it and still runs also as the day I bought it. While there are some small decreases in performance, it'll not be noticed unless you take the car to the track frequently. As for an engine malfuntion, knocking and wha not isn't a concern for a sophisticated engine like yours. Also Road and Track and Motor Trend staff give the same opinion as I have.

yes you may be able to but it'll just ruin the in general performance of your car. why save on the small % in the cost? and to think that you're able to purchase a MB S420

premium for all mercedes