My father has just purchased a 1998 C230, the year before it was supercharged. He asked me if it would be okay to run regular (87 octane) in it as opposed to premium (91 octane). It says on the gas door to use premium, but I was curious if it would harm anything if regular was used? In my 1988 300E, I have read on this site that it is fine to use regular. I understand that in some cases it is recommended to work better with old injectors etc. I also have a friend with a 1994 C220 that has only used regular for the past 5 years with no problems.

What are your opinions on this?

TIA,
Steve

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1997 E320
1990 Nissan 300ZX Twin Turbo (Stage X+)

All the the newer MB engines have "knock" sensors that detect spark knock. IF the check engine lamp comes on for MAXIMUN retard on any cylinder then the engine requires higher octane fuel.
The engine has 10/1 compression & should have at least 90 octane for CORRECT performance.

Long term damage can be done by using low octane fuel.
However if the engine is never accelerated briskly I doubt if any damage would be done.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I've done it with 87 octane. The car runs ok on regular unleaded. Don't jump on the throttle. If you really calculate it you do loose 1-2 mile per gallon over premium. You do the math. Check your gas milage with premium & midgrade. I settle for midgrade with premium ever few fill ups. I put my car through mid to heavy accelleration .

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T

My VW Passat requires 91 oct or higher. I can put in lesser gas, but the engine computer will adjust the timing to prevent engine knock. The overall performance and fuel economy would go down. So, it's false economy to put in lesser gas.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

I currently use 87 octane for a 1993 300E, and have never experienced any problems, but I accelerate very slowly, and do not tow any vehicles, nor load down the car with a lot of weight, etc....

Premium gas here is about 10 cents per litre more than regualr gas. Suppose you drive 20,000 kilometers per year, and average 9.5L/100km's in the C230 (my city driving mileage)

Over the course of the year, you'll burn 1900 litres of fuel. At a $0.10 premium for premium (get it...) you spend an additional $190.00 per year.

190 bucks? In the overall scheme of maintaining and owning a Mercedes, $190 per year is chump change. I wouldn't bother.

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John Shellenberg
1998 C230 "Black Betty" 240K

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