UnLeaded fuel for 230.4

[Driver]

Is it necessary to use an additive in unleaded in a W115 230.4 or will they happily run on unleaded?

[Bartman4800]

Every mercedes after 1950 has hardened valve seats in the cylinder head.
No need to add an additive.

Consensus here is though, to at least use RON 95 fuel.

Bart

[AMG]

Every mercedes after 1950 has hardened valve seats in the cylinder head.
No need to add an additive.
Consensus here is though, to at least use RON 95 fuel.

Bart

Yep, covered a bazillion times. Use NO ETHANOL. so in most cases that is 98RON, because most 95 is now also being blended with ethanol. Always check at the bowser before you fill it.

Car will run much better on 98 if you tweak it as well. Less critical on carbs, but my own opinion is that any D-jet or K-jet car should only ever run 98RON and regular fuel filter changes to ensure contaminant free fuel systems. Prevention is far better than the cure.

[VFRBoy]

Can I ask why no ethanol? I like the 95 e10 in my other (modern) cars, same price as normal 91 but the tech picks up the 95 and gets better performance.

What does the ethanol do to a 51 year old Benz?

[Ivanerrol]

Your car was originally tuned for Super leaded fuel. This was leaded 98.
Modern unleaded 98 is an equivalent , the octane rating is just enough to be considered the equivalent to leaded 98. The real octane equivalent is unleaded 100. It's the chemistry.

Ethanol contains a little moisture content which is handled better by modern engines because they run much "hotter" than historic designs.
The chemical properties of ethanol attack the rubber compounds and other seals of older design engines.

The government of the day attacked Mercedes and other Euro manufacturers when ethanol was introduced and forced them into issuing certificates of compliance. A very political subject.

And F.W.I.W. Australia has crap fuel. Produced by refineries which should have been retired or upgraded decades ago. 98 is imported from Swingapura.