Hi I'm new here and new to Mercedes. I'm currently researching the mid to late 80s 190E, 300E, and 420SEL. I've noticed these cars weren't big on the overdrive gears but that's ok as it seems the engines are more than adequate for high speeds and efficient despite that fact. But then I noticed someone stating that the 300E requires premium fuel. Is premium absolutely necessary, and is it required for all of the mentioned models?

Any help appreciated.

Thanks!!

 

No, I dont believe its necessary as they should have knock sensors. my 1991 300ce was run on regular for its whole life up until this summer. Sure, it seems a little more spritely now, but it was fine before!

 

It will run fine most likely as people have put in 87 its life. I always put in 91 though and put in fuel injector cleaners every oil change

 

Guess again.

There are no knock sensors.

The only way for a 180 cubic inch engine to produce the horsepower the M103 produces is by high compression. High compression requires premium fuel. You risk damaging your engine otherwise (unless you live at 5000 fit ASL or above).

 

-The regular fuel here in this country is 95 (thats what I get for free!) The premium (AKA 'Super' here) is 97 Octane. I guess 95 is more than enough for this baby.

 

dont some countries have a different method for finding octane number? which is why germany has 100+ octane available everywhere

 

hmmmm.. well I am no Chemical Engineer. But I guess thats possible. Cause 87 in US versus 95... thats a big difference.

 

USA octane numbers are an AVERAGE of two methods.

 

what if I have m104 engine mm?

 

Thanks guys for the responses so far. Keep up the discussion cause I'm learning more and more.

I've had experience with Cadillacs and friends with Caddys and they highly recommend premium for the Northstar v8s but I have never heard a knock in any of them. Could be just me, and could be just a Cadillac thing?

I take it there are no knock sensors for any older model Mercedes either?

 

Actually it depends on how you drive or tune the car. Right now i'm running 87 octane everyday and i have no problems. One thing you have to do is not to press so hard on the gas. You will know how much by when the engine starts to ping. Aslong as you don't accelerate too hard and drive nice and smooth you can run 87 forever..If you want to push the peddal alittle more then i suggest you run 91 octane with an octane boster. Also run a hotter plug if your going to use 87.

 

My suggestion would be to always do what the manufactuar recomends when it comes to gas or anyhting else. it help secure a long and healthy life for your vehicle... even though it's tough with these damn gas prices.

me> <premium gas

 

I tried 87 in Mine and she started running like an old maid.

SO I moved up to 89. She moved much much better.

Then one day I said ... Stop holding on to your wallet and put in 93

She smoothed out in such a way I had never felt. Everything about her FELT and RAN much better.
Tap the pedal... She was very responsive....

so 93 it is for me......

US figures...

 

"300" means 3 liters and that means 180 cubic inches.

A little (!) smaller than the usual 350 V8 Americans are used to.

Yet, the M103 produces nearly the same horsepower, that is about one horsepower per cubic inch. Unheard of as regards most American engines.

To do that requires a high state of tune which means high compression which means premium gas.

If you want to burn regular, get a Chevy.

 

If you read in owner manual you will find that if you close to sea level MB recommend 91 and up. If you live 3000 ft or more above sea level MB recommend mid grade. My MB is E320 1995 I buy gas from Costco so it is not that bad to pay for premium gas. It cost about 20 cents more than regular gas so I dont mind paying more. I dont drive this car that much anyway. I still think premuim gas is the way to get your car performs.