Use of regular gas in european automobiles

We have a 2003 Mercedes C230 car. It now has 77,800 miles, and for the third time, we have low compression in the #3 cylinder. The valve springs were replaced at 49,000, and the head was replaced at 51,000. The dealer now tells us the head must be replaced again. He told us it is because we have been using regular gas, instead of premium as recommended by the manufacturer. I seem to recall you guys have held the position that premium gas was a waste of money, and a con-job. In fact, you both convinced my wife and me that there was no advantage in using regular. Now what do we do? How do you feel about using premium gas in a car like our Mercedes C230?

Premium is a waste of time in a car designed for regular. However in a car made for premium, it is foolish to use regular.

If the manufacturer recommends premium, then regular will not damage it, but it will reduce mileage and power. You may loose power with out saving anything since you will just be buying cheaper fuel, but more of it.

If the manufacturer requires premium then you can add possible engine damage to the list above.

Note: If you car was sold in Europe the recommended octane is not on the same scale as is used in the US. You may need to adjust.

Why is this question being posted again? There have already been a large number of responses to the original posting of the question, and they have been good responses.

Don’t vehicle manufacturers supply that information on the fuel cap and specify fuel requirement in the OWNERS MANUAL?

Oh yeah, I forgot. People don’t know where the owners manual is kept.

Posting a second time with the same complaint and not answering any questions on the first complaint leads to a raised eyebrow to put it politely.
How about filling in some blanks first.

THIS is your original post. To bring up a post (I know, sometimes, it’s hard to find.), click on Search, on the red banner, up there. Put the title of your original post in the Keyword block: “Use of regular gas in european automobiles”. …and, here we are!