maste3w0ng

hey guys i drive a 300e and for about 5 years my dad changed from putting unleaded premium (91) to (87). How will this affect the car?

mrjd2636

read your manual. i read mine a little bit last night and i think it said; if you have to fill it up with regualar fill it half full. im not sure but i think with the 300e,400e,500e you can mix the gas 50/50, half premium and half regular.

Smokiesman

Been running RUL in my E420 V8 for well over a year with no problems. I live in the mtns. where you have lots of steep hills and long grades. Has yet to miss a beat! The only thing I do is pour in a can about once a month of SEAFOAM to keep the fuel system in top shape.

Smokie

http://www.seafoamsales.com/motorTuneUpTechGas.htm

NorCal124

On your gauges you will notice it says "premium unleaded only." Whether you choose to follow to it is up to you.

PaulX608

Why even put yourself in a position to wonder? Is the $4 per tank really that precious to you?

oliverb

If you do a search, you will find lots of opinions on octane requirements. MB says 91 (RON/MON) octane minimum. As an engine ages, carbon deposits build up in the combustion chamber increasing the compression ratio above the original 9.2:1. Older engines will often ping on a pull where they did not with fewer miles. It is always your choice but your older 124 does not have a knock sensor to automatically retard timing if the engine begins to knock on lower octane gas. It is theoretically possible to damage the engine if run like this for a long period of time. All "pinging" (detonation) is not clearly audible. An engine may be pinging slightly but not loud enough to be heard. Additives in higher octane gasoline control the burn rate of the gas, sort of evening out the burn rate of the fuel to avoid detonation. Gas in my area of the country is 87/89/93 octane. If you do half-fill mixes of 89/93 octane you will achieve an approximate 91 octane. With the 18 gallon tank in most 124s, you would save between $1.80 - $3.60 (depending on the cost difference between mid-grade and high-test) if the tank were bone dry. If you fill up with 18 gallons once every week, the yearly savings would be between $85 - $190. How much would it cost to repair a damaged engine? As has been said on many MB sites, many times, if you want an econobox that runs on the cheapest gas, buy one. The Benz was never designed to be such a car. I am not knocking a person's personal choice for their vehicle, just stating the facts you, as a young owner, should be aware of when making your choice.

neanderthal

i drive on **** poor gas (california) and use 87 most ofthe time. sometimes i get a stumble off idle in which case i use 91 and a bottle of fuel injector cleaner, give her the old italian tuneup, and she is right as rain.

if you drive your car hard enough you will avoid/ preclude the carbon deposits.

YNVDIZW124

well i put 87 octane and my car ran like shiet so i would suggest spend the extra money and it's the same mile per gallon if you really look at. Also run your car from 55 to 90 for about 1/4 mile with some fuel injector cleaner. do this about twice a month.

MOBB

it's best to use 91 because thats what it says to use. we have 94 here do you guys get 94 there?

Legoinsaniac

There are gas stations here in Columbus that have 94, but I just stick with the 91. On tuesdays at the exxon station 91 is the same price as the mid-grade. Kinda nice.

MOBB

The same price for 91 as mid grade thats cool i wish they had that here.