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Mercedes 300 SL-24
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Discussion Starter #1
I've been reading what everybody writes here and elesewhere regarding unleaded fuel. I also have been asking around.
Mercedes only started to build (at least for Europe) special engines to be catalyzed (KAT) or to use unleaded (RUF?) in 1986. Before that all european engines were to be used with leaded fuel.
I have a 1981 engine. Many of you here also have pre-86 engines. We can't find anywhere in EU leaded fuel.
Shall we use unleaded 95 or unleaded 98 or additivated fuel or add some additive to unleaded?
In other forums I heard that people using unleaded really had problems after sometime. People using additivated fuels never had any problems. In the workshop that takes care of my SLC they say I should use unleaded 98.
In this forum, someone already wrote that asked Mercedes (UK, I think) and they said not to use additivated fuel but unleaded was not advised either.

What shall we do? Use unleaded 98 and replace valves after 20 or 30000 km? Or use additivated and have the same problem? I tried to find someone here at Mercedes Portugal to answer me, but I'm having trouble just to get an appointment at the shop...

Jorge
'81 280 SLC
 

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280SL 1982
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18 Posts
Which fuel?

I contacted MB with the VIN number of my vehicle and I got the following response:

Mr. Gregory

In reference to your query as to whether your vehicle is suitable to run on unleaded petrol our technical specialists have given the following advice.

The best solution advised by Mercedes-Benz is to have hardened seat valve rings fitted to the vehicle in order for it to run continuously on unleaded fuel.

However, unleaded or lead replacement petrol may still be used if a normal driving style is observed and valve clearance is checked on a regular (6500 miles) basis. Lead replacement petrol is a new fuel type and should accommodate for the loss of lead and compensate for extra wear. Mercedes-Benz do not consider this fuel different from the standard 98 ron premium unleaded types.

Any unleaded fuel with a rating of 95 ron or higher may be used as well, where the higher (usually 97 or 98 ron) will give better performance. Generally, whilst using lead replacement petrol or 98 ron unleaded, timing adjustment should not be necessary. If engine pinking does occur whilst using unleaded or lead replacement petrol then visit your dealership for correct engine timing adjustment.

Mercedes-Benz advises you not to use fuel additives or any other products that claim to be lead replacing.

We hope that this information proves satisfactory and answers your query.

Should you have any further requirements, please do not hesitate to contact us at [email protected]

Yours Sincerely
Mercedes-Benz Customer Assistance Center N.V.'

Send them your VIN number and see what they say.
 

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1986 560-SL
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57 Posts
Fuel

I would use the fuel that the engine was manufactured for. If your engine was made for leaded fuel, get the additive. As you noted, it does make a difference in the life of your valves, spark plugs, etc.

If you use the fuel specified for the engine, you should NOT have valve problems for a long time.
 

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Mercedes 300 SL-24
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111 Posts
Discussion Starter #4
Re: Fuel

I would use the fuel that the engine was manufactured for. If your engine was made for leaded fuel, get the additive. As you noted, it does make a difference in the life of your valves, spark plugs, etc.

If you use the fuel specified for the engine, you should NOT have valve problems for a long time.
I would use it... If leaded fuel could be found in Europe... Additivated unleaded is no solution.
Thanks for the idea anyway!

Jorge
'81 280 SLC
 

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Always Remembered RIP
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520 Posts
Just want to point out for those of us in the UK that leaded petrol is still available. ...

Just want to point out for those of us in the UK that leaded petrol is still available. Admittedly it's only stocked at a handfull of garages and costs around 99p a litre, but if your like me and don't do a great deal of mileage it might be worth the extra piece of mind.

Heres a list in PDF format (Adobe Acrobat document)

http://www.leadedpetrol.co.uk/leadedpetrol.pdf
 

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Mercedes 300 SL-24
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Discussion Starter #6
Why don't I live in the UK???
Here it's very hard to find additivated!
There's no such t...


Why don't I live in the UK???
Here it's very hard to find additivated!
There's no such thing as driving classics... Even in weekends you rarely see a classic car passing by.
And old Mercedes only diesel-powered! It's amazing the ammount of people that ask me if my SLC is diesel-powered...

Jorge
'81 280 SLC
 

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Always Remembered RIP
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520 Posts
If your having problems obtaining an additive why not see if you can get it imported fro...

If your having problems obtaining an additive why not see if you can get it imported from somewhere.

If that fails I would be willing to post some to you. I could easly pick up an extra bottle of Castrol Valvemaster and I would'nt have thought postage to you would cost a great deal.
 
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