Premium diesel - worth it?

[evoke]

I have a very high-mileage C5 diesel and was wondering whether it would be worth running a few tanks of the premium diesel fuel (like Shell V-Power Diesel) just to clear out any muck that has built up over the years. It'll cost me an extra £6 or so per tankful. Opinions?

The car is running fine but I have no idea what fuel it's had over the last 4-5 years and 137,000 miles.

[Bick]

millers is a cheaper option as it costs about £1.20 a tank

[isisalar]

I used Shell V power on my wife's old 106 diesel when I had to use it for a while and it certainly cleared out a few cobwebs and improved the running generally.
I have tried all sorts of additives over the years and the only one that seems to work is Slick 50 fuel system cleaner, just make sure not to dilute it too much, the gallons mentioned on the tin are American gallons.
If nothing else your car will feel like it's got a bigger engine while it's in there. It's quite expensive, about £13 last time I checked, but it's very effective.
Cheers
Paul

[Hell Razor5543]

I normally use standard Shell diesel, as it has the same cleaning additives as the V-Power fuel. The reason that the V-Power produces more power in the engine is simple; it has a higher octane level. This results in a bigger bang for the same amount of fuel.

[Peter.N.]

I have used supermarket fuel for the last half a million miles or so without problems. I did once accidentally fill mine with 'V' power but didn't notice any fifference.

Peter

[qprdude]

I have used supermarket fuel for the last half a million miles or so without problems. I did once accidentally fill mine with 'V' power but didn't notice any fifference.

Peter

Same for me Peter. Only used V power by mistake at a strange filling station once. Never noticed the slightest difference in noise, power, or anything. I'm sure there must BE a difference as supermarket stuff is supposed to have additives that other stuff doesn't, but the C5 has never complained about it, so as long as it is happy on the cheap stuff, so am I.

[evilally]

I normally use standard Shell diesel, as it has the same cleaning additives as the V-Power fuel. The reason that the V-Power produces more power in the engine is simple; it has a higher octane level. This results in a bigger bang for the same amount of fuel.

Octane relates to unleaded fuel, diesel fuel has a cetane number. Premium diesel has a higher cetane index than standard diesel fuel. In a nutshell this relates to the delay between the fuel being injected, and combustion starting. On newer turbo diesels this can result in increased torque and response, but the effect on older diesel engines, particularly those with no electronics, is significantly less.

The “premium fuel cleans your engine” debate has been long time running and people have different opinions. If there was any hard evidence one way or another I don’t think there would be a debate. In my view the only part of the engine that the unburnt fuel touches is the inside of the injectors. As it happens, diesel fuel is an excellent cleaner anyway and many use it to clean coked engine parts. Personally I don’t buy into the “it cleans your engine” marketing. A far more effective way to keep your engine healthy and clean is to shorten the oil change intervals.

[old'uns]

I put anything in mine, never noticed anything different from the odd time i put in a 'premium' fuel, apart from the cost
only thing i've ever noticed is the fuel i put in from Europe never quite seems to go as far, 40-50miles less per tankful, lower rated i recall than UK - Bio content nearer 10% than 5 ?

money wise, if 'premium' costs £6 per 65l more i'd expect to see at least 40-50 miles more per tankful?

mechanically never had any issues fuel-wise, usual fuel filter changes, injectors etc never touched in 242k.

last few years i 've been doing 65l per week, sometimes more, money is money, putting a tub of injector cleaner in every few months will do me.

[Northern_Mike]

I have a very high-mileage C5 diesel and was wondering whether it would be worth running a few tanks of the premium diesel fuel (like Shell V-Power Diesel) just to clear out any muck that has built up over the years. It'll cost me an extra £6 or so per tankful. Opinions?

The car is running fine but I have no idea what fuel it's had over the last 4-5 years and 137,000 miles.

Mine gets whatever is cheapest and on my way. Usually that's Asda or Sainsbury's. I've never had any problems, nor have I ever used any fuel system cleaner guff.

I have to use Super/V-Power/BP Ultimate/Tesco 99 RON in the Subaru, which is slightly more expensive. It doesn't like crap fuel at all,being a Jap import.