Only prolong use of low grade petrol will damage your engine. It wouldn't damage your engine for only one tank if you drive gently.
Well, since there hasn't been a W126 produced in the past 8 years, warranty
problems aren't a factor. An occasional tank of regular unleaded by accident
> probably won't cause harm but premium is a recommended.
>
> If it rattles with the tank of accidental regular, just remember to get the
> higher grade next time.
>
> Which model is it?
>
> > Mercedes-Benz USA states in their Service and Warranty Information Book
> > that they may deny an emission related claim if it can establish that the
> > failure or the malfunction of an emission control system part results
> > directly from the use of non-premium low octane fuel in the engine (i.e.
> > fuel with an anti-knock index of below 91 as displayed on the fuel pump).
> > Saving a few bucks in the short term may be more costly in the long run. > The
> > Federal Emissions Warranty is 8 years/80,000 miles.
> >
> >
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~
> > > Just bought a 1990 300SE after many years of an Audi 4000S and I love > it!
> > > Silly me, with my last fill-up I used Regular Unleaded 87 octane instead > > of
> > > Premium 93 octane, which Mercedes says is required.
> > >
> > > So far it is running OK - just wondering if there will be long-term
> > > effects, or if this is actually a scam and 87 octane is perfectly OK for
> > > this car.
> > >
> > > With gas prices above $2.00 for a gallon of 93 octane, it would make a > big
> > > difference if 87 is fine.
> > >
> > > Thanks!
> > > Pete
> >
> >
>
>