If you aren't in the UK you may want to stop reading now

Hi, I've just purchased a 2019 C63S AMG and according to the manual, and the sticker under the fuel cap, 98 RON fuel must be used. In the UK 95 RON is the standard unleaded fuel.

I understand why 98 RON should be used, but I'm struggling to actually find a garage that sells 98 RON unleaded fuel in the UK! I was at my local dealers yesterday and asked for their advice. Their response was that nobody had ever asked that question before, which really surprised me. They suggested as nobody had asked, I should be fine using the standard 95 RON fuel. I'm not so sure!

I have a Morrisons and Shell petrol station near to where I live. Morrisons sell 97 RON (Super Unleaded) and Shell sell 99 RON (V-Power). I've read that BP sell a 97 RON (BP Ultimate) fuel. I'm not aware of ANY petrol stations that sell 98 RON, which seems to be peculiar to mainland Europe.

So, what fuel should I use for my Merc? What fuel are you guys and girls using in your AMG's?

 

I only use V-Power in my cars.

 

I'm not in the UK , but I am from Europe and I drove mine all over Europe for the first 2 months of ownership. At that time the engine was programmed for European fuel levels and got reprogrammed once the car arrived in the USA. 98 RON is the minimum recommended fuel grade. It doesn't mean you have to fill exactly 98, but 98 or higher, so you should fill it with Shell V-Power 99. In Germany for example, V-Power is 100 RON and BP Ultimate is 105 or 103 RON (don't recall exactly). 98 RON is rare in Germany as most of the premium grades are at least 100 RON. They drive faster so that makes sense. In other European countries V-Power is typically 98 RON, but looks like in the UK it's 99 RON (I've never driven in the UK). That's all good. Your owner's manual gives you some direction. You can fill 95 RON in a pinch, but if I remember correctly the owner's manual clearly states you should only fill half the tank and not drive the car hard with full throttle etc, until you get an opportunity to fill the rest with 98 or higher. All modern engines adjust their ignition timing to avoid knock. If the fuel grade is too low, then there might be premature ignition, which is what engine knocking means and it's not good for the engine. Premature ignition is more likely with turbo charged engines due to the compressed air being hotter than ambient air, so you should really use the recommended fuel grade or higher and that's why the owner's manual says to not drive it hard to keep those turbos from getting real hot and increase the chance of knocking. As I said the engine will do it's best to avoid knocking by retarding the ignition.

 

Tesco and Shell both do 99 RON fuel, I personally use Shell V-Power in mine.

 

Thanks for the responses so far, it looks like Shell V-Power is the favourite.

On my first visit to my local petrol station I used Morrisons Premium Unleaded, which is 97 RON, so think I will try Shell V-Power next time. I owned my previous car, a Jaguar XKR, from new for 13 years and always used standard fuel (95 RON) without any obvious issues. In the early days, I did try some higher octane fuels and appeared to get marginally better mpg, but it wasn't worth paying the extra for. My "new" Merc is 7 months old (an ex lease car) and I have no idea what fuel was used by the previous owner. As the handbook and note under the fuel cap is very specific about using 98 RON, I will stick with using a higher octane.

 

Shell V Power all the way. Don't put anything else in it

 

I would only use 99 RON in your case, or whatever highest is available. However Im sure you could run 95 RON with no issues except for slightly decreased power.

 

Shell V Power and nothing else.