Is posh diesel worth it?

[PlacidoD]

Can I steer this thread in a slightly different direction and ask a simple question. An increasing number of MoHos are fitted with diesel space and water heating. Do either additives or fuel quality have any bearing on that subject? I presume that a Truma system or whatever will happily guzzle whatever you put in the tank. However you maybe do not want to feed it expensive posh stuff? So a a sensible strategy might be to use the posh stuff and additives in summer (when you are likely to do more miles anyway) but stick to branded economy diesel over the winter months? Or will additives and posh diesel benefit a Truma or whatever system?

Actually I have no idea how much diesel these units use. Anybody any idea how many litres such systems use in a typical season of use?

 

[L' Hobo]

There’s lots of mis information on fuels and lots of people saying they’ve used cooking oil for 20 yrs/millions of miles without issues, the fact is those engines are old school and not the engines that most of us have in our vans.

If your van is 10 yrs old or newer then you have a fairly complex fuel system that wont tolerate poor fuel for very long, as has already been said all fuel sold has to meet EN590 spec for Diesel, the fact is that this is a minimum std so even the cheapest fuel should achieve this.

The better fuels (think branded) far exceed the minimum std, this is particularly important where lubricity is concerned as Diesel, in it’s raw state is no longer a lubricant so it needs lubricity enhancers to protect the moving parts of your fuel system, the better the fuel the better quality additive pack - this applies to all of the additives that help fuels deal with other issues such as water etc etc.

It may have changed since I was heavily involved in fuels but the Bio aspect of EN590 fuel must be 7% (hence the B7 classification) but the rules were (and probably still are) that 7% of the diesel fuel leaving a refinery over a period must be bio rather than all fuel leaving the refinery must be 7% bio - there is a difference.

Bio fuels are usually from a FAME base stock that meets EN14214 (I think) and are made from organic materials which over time release the water content, thats why Diesel doesn't keep like it used to. Interestingly the MOD had bunkers of Diesel from the 1950’s and 60’s, it was still a useable diesel fuel that an older engine would be quite happy to run on.

The 7% in B7 in practice means that some fuels come out with very little Bio and some come out with more than the 7%, think about it - if you manufactured fuel and you had to put something with your fuel that lowered your quality would you put it in fuel that you sold through your own retail outlets (or those of other fuel manufacturers that supplied you fuel in other locations) or would you sell it to competitors who didn’t supply you with fuel and whose core business wasn’t fuel.

We did a survey where our field teams took fuel samples from lots of pumps around the country, we put the fuels in a locker and left them to see what would happen, after 3 or 4 months some had settled and began to separate, the worst of which was about 40% clear liquid with 60% golden liquid floating on the top, it was assumed that the clear liquid was water and the golden liquid was Diesel although we never tested it- what struck me was the fact that none of the Branded fuels changed their appearance at all.

We had relationships with all the fuel manufacturers in the UK as both customer and supplier, during discussions with chemists and senior staff no one was surprised at what we found.

Another discussion with the distribution manager of a major fuel supplier told me that he could put 20,000 ltrs of milk into a busy keyfuels bunker like the one at South Mimms and be long gone before anyone worked out there was a problem. This was a discussion about how they would get rid of fuel that was past it’s best - it was stressed that they wouldn’t do that though…

Its a long ramble but my take on the fuel question is that theres no need to buy premium diesel and if you buy branded fuel from a fuel supplier you wont go far wrong, if you buy it from someone who does fuel as a sideline then eventually you could have a problem but it probably wont be related to the fuel in the tank at that moment.

Personally I would buy supermarket fuel if it was all I could get and as long as it was going to be used fairly quickly. i would never buy it if I had a choice - all in my own personal opinion of course, anyone reading this far should do what they feel is best.

Nice piece except the part I don't understand?
60 odd years ago when I was being trained to be a ships engineer, I seem to remember being shown a picture of natural crude oil distillation.

This showed a column, black at the bottom and clear liquid at the top and various layers of lightness in-between.

We were told the jet black at the bottom was the sediment from leaves, plants, insects etc. from the decomposed plants from which the oil was made.
Slightly higher black was what we called crude oil.
Then various viscosity of what we would call heating and engine oils

On top of that DIESEL
Parrifin
Lower octane petrol.
Then at the top, Higher octanes of petrol.

I know that is simplistic but, IF that is correct, why does Diesel " in it's raw state" need ADDED lubricants and not other fuels?

 

[L' Hobo]

Can I steer this thread in a slightly different direction and ask a simple question. An increasing number of MoHos are fitted with diesel space and water heating. Do either additives or fuel quality have any bearing on that subject? I presume that a Truma system or whatever will happily guzzle whatever you put in the tank. However you maybe do not want to feed it expensive posh stuff? So a a sensible strategy might be to use the posh stuff and additives in summer (when you are likely to do more miles anyway) but stick to branded economy diesel over the winter months? Or will additives and posh diesel benefit a Truma or whatever system?

Actually I have no idea how much diesel these units use. Anybody any idea how many litres such systems use in a typical season of use?

I would have thought, IF posh fuel was needed, it would be better in the winter when the heaters are used more, no?

 

[L' Hobo]

NEAR the bottom but not ON the bottom. Water, and usually crud, is heavier than diesel and that inch can make an awful lot of difference and when that inch is exceeded, is when you really have problems.

I should have said, IF I do have any engine fuel problems, the first thing I do is change the fuel filter and examine the old one.
In the world of heavy diesels, we were always taught to eliminate the easy bits first.

 

[PlacidoD]

I would have thought, IF posh fuel was needed, it would be better in the winter when the heaters are used more, no?

I just don't know. I very much doubt that posh stuff is needed. I just wonder if it gives any advantage at all and how much diesel such units guzzle. It may be so little as to be an irrelevance.

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[John Barrett]

Nice piece except the part I don't understand?
60 odd years ago when I was being trained to be a ships engineer, I seem to remember being shown a picture of natural crude oil distillation.

This showed a column, black at the bottom and clear liquid at the top and various layers of lightness in-between.

We were told the jet black at the bottom was the sediment from leaves, plants, insects etc. from the decomposed plants from which the oil was made.
Slightly higher black was what we called crude oil.
Then various viscosity of what we would call heating and engine oils

On top of that DIESEL
Parrifin
Lower octane petrol.
Then at the top, Higher octanes of petrol.

I know that is simplistic but, IF that is correct, why does Diesel " in it's raw state" need ADDED lubricants and not other fuels?

I like your post: its a cracker!

 

[Coolcats]

NEAR the bottom but not ON the bottom. Water, and usually crud, is heavier than diesel and that inch can make an awful lot of difference and when that inch is exceeded, is when you really have problems.

Makes no difference, the pipe is at the bottom of the tank the fuel sloshes around shaken and stired whilst driving…you also have a fuel filter for siphoning out any particulates. Should water mix with diesel you will have a colloid. Water will float to the top if you were to get anywhere near that you will have run out of fuel….

 

[MichaelT]

Not sure about posh diesel but when in france I try to use Total as the engine definitely has more power and is quieter and gets more MPG.

IN Spain I bought the really cheapo stuff and no issues but that was interspersed with normal supermarket and cespa/repsol stuff.

 

[L' Hobo]

I just don't know. I very much doubt that posh stuff is needed. I just wonder if it gives any advantage at all and how much diesel such units guzzle. It may be so little as to be an irrelevance.

All I can say is, I remember a TV programme called Fifth Gear?,( no not the one the 3 Stooges the other one) did a comparison test when they first appeared on the scene.

Their conclusion was, "there was no significant increase in mileage or performance so save your pennies! "

 

[enark]

My last fill up was done at costco with super diesel, at £1.30 usually ppl keep away from the super fuel, so I drive up and fill. All are in the queue for the cheap stuff.

? Costco only sell one type of diesel, thats super.

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[L' Hobo]

Makes no difference, the pipe is at the bottom of the tank the fuel sloshes around shaken and stired whilst driving…you also have a fuel filter for siphoning out any particulates. Should water mix with diesel you will have a colloid. Water will float to the top if you were to get anywhere near that you will have run out of fuel….

Can I ask, IF what you say is true about water floating on top of diesel, why has ALL fuel filter manufacturers put there water drain off screw at the BOTTOM of their product?

Perhaps you should tell them they should be at the top?

 

[Coolcats]

Can I ask, IF what you say is true about water floating on top of diesel, why has ALL fuel filter manufacturers put there water drain off screw at the BOTTOM of their product?

Perhaps you should tell them they should be at the top?

are you sure that’s for water ?

 

[L' Hobo]

are you sure that’s for water ?

YES!

 

[Raul]

? Costco only sell one type of diesel, thats super.

That makes sense, each time I gone there never found a regular diesel pump. I'm new to Costco, filled up 3 times so far.
Thanks for the info.

 

[Ian_H]

Water will float to the top if you were to get anywhere near that you will have run out of fuel….

Wrong!
Diesel has a density of 0.838 kg per litre

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[Daffy64]

Nice piece except the part I don't understand?
60 odd years ago when I was being trained to be a ships engineer, I seem to remember being shown a picture of natural crude oil distillation.

This showed a column, black at the bottom and clear liquid at the top and various layers of lightness in-between.

We were told the jet black at the bottom was the sediment from leaves, plants, insects etc. from the decomposed plants from which the oil was made.
Slightly higher black was what we called crude oil.
Then various viscosity of what we would call heating and engine oils

On top of that DIESEL
Parrifin
Lower octane petrol.
Then at the top, Higher octanes of petrol.

I know that is simplistic but, IF that is correct, why does Diesel " in it's raw state" need ADDED lubricants and not other fuels?

Thanks, I made the point in my thread that diesel from past times was a much simpler product, in fact up until about 15 yrs ago it was never classed as a flammable product as it’s flash point was above the level for the classification, these days it’s defiantly a flammable product.

There is no raw Diesel that gets into the supply chain these days, back in the day the natural was the lubricant in fuel but with the advent of Low Sulpher fuel and then ULS fuels with only 5ppm of Sulpher then the addictive pack has to contain lubricity enhancers.

Paraffin has high Sulpher levels and petrol doesnt need it, with reference to Red diesel, there are at least 2 grades, one is basically paraffin with a dye, suitable for heaters and the second is a road fuel very similar to EN590 so dont get your Red’s mixed up.

 

[Daffy64]

Wrong!
Diesel has a density of 0.838 kg per litre

Correct, Diesel floats on water.

 

[Coolcats]

YES!

I think you will find it’s more complex than that firstly make sure you have a good filter

Wix Filters emphasizes that choosing a premium-grade fuel filter is vital; fuel filtration configurations can vary. Some applications have a primary and secondary filter where one is for contaminants and one is for water separation. If your trucks have a single fuel filter than the primary filter should function both as a fuel filter and water separator. This dual role not only ensures a prolonged lifespan for the diesel injection system but also promotes efficient engine operation.

Just thinking about any water that may collect at the bottom of an engine ignores the overall issue.

Wrong!
Diesel has a density of 0.838 kg per litre

You are of course correct water is heavier than diesel

 

[Daffy64]

Can I steer this thread in a slightly different direction and ask a simple question. An increasing number of MoHos are fitted with diesel space and water heating. Do either additives or fuel quality have any bearing on that subject? I presume that a Truma system or whatever will happily guzzle whatever you put in the tank. However you maybe do not want to feed it expensive posh stuff? So a a sensible strategy might be to use the posh stuff and additives in summer (when you are likely to do more miles anyway) but stick to branded economy diesel over the winter months? Or will additives and posh diesel benefit a Truma or whatever system?

Actually I have no idea how much diesel these units use. Anybody any idea how many litres such systems use in a typical season of use?

Just use ther stuff you run your engine on, thats what they are designed to use, if its good for your engine then it’s good for the heater.

I have experience with Truck cab heaters from Webasto and Eberspacher and they would typically use around 1 ltr in 24hrs assuming they were maintaining a temperature rather than running flat out - compared to a 12 ltr diesel that would use 1 - 1.5 ltr an hour on tick over.

 

[Coolcats]

YES!

But it’s more complex than that. And Fuel filters are designed to filter out both contaminants and water which is one reason you shouldn’t go for cheap filters.

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[BouncyBoatFolk]

On a 200ltr tank and if my mental arithmetic is right, that's an extra 14p+ a litre.
How bigs your tank because around here , it's only 5p a litre extra?

PS. I put a small bottle of Redex in mine about once every 2 months in the winter.
It certainly makes a difference!

The best advice I can give after many years of fixing, owning and operating heavy diesels is, only use the top 2/3rds of your fuel tank, the bottom third is where you will find any water and crud if there is any. Injector tips don't like dirty watered down diesel!

Hhmmme, I'm struggling with the last bit of advice. I've heard it said many times about not using the fuel from the lower portion of the tank. However to the best of my knowledge the fuel take off point is always near the bottom of the tank unless tanks now have some sort of floating fuel pick up pipe. So to my mind the ' cleaner' fuel will probably be the last bit used. I do agree running a tank very low is not good, and refilling ASAP is also a good policy.
Mike.

 

[L' Hobo]

Hhmmme, I'm struggling with the last bit of advice. I've heard it said many times about not using the fuel from the lower portion of the tank. However to the best of my knowledge the fuel take off point is always near the bottom of the tank unless tanks now have some sort of floating fuel pick up pipe. So to my mind the ' cleaner' fuel will probably be the last bit used. I do agree running a tank very low is not good, and refilling ASAP is also a good policy.
Mike.

post #54 will possibly explain it?

 

[Barclaybasher]

Over 40 years ago I drove a petrol CF Bedford van - cost me £150, a 'shed' - to Spain.
I broke down in France, engine died, looked under the bonnet at the glass bowl on the mechanical fuel pump.
It was full of clear liquid - water
Unclipped the bowl, which emptied it, refitted and pumped through some yellow stuff - petrol and off I went
Had to do the same one more time and made it to my destination

 

[L' Hobo]

Over 40 years ago I drove a petrol CF Bedford van - cost me £150, a 'shed' - to Spain.
I broke down in France, engine died, looked under the bonnet at the glass bowl on the mechanical fuel pump.
It was full of clear liquid - water
Unclipped the bowl, which emptied it, refitted and pumped through some yellow stuff - petrol and off I went
Had to do the same one more time and made it to my destination

Had some glass bowls on my early D Series trucks, those were the days of hanging small paraffin heaters near the fuel line on frosty nights and a bonfire under the engine next morning!
Those were the days!

 

[funflair]

Is posh stuff better or not I don't know but by all probability it is better for the engine and fuel system so I use it quite often, not sure if I get better MPG as I don't keep good enough records but if the engine likes it that's good enough for me, experienced people on this thread seem to suggest it's not money wasted

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[BouncyBoatFolk]

post #54 will possibly explain it?

That'll teach me, speed reading, I missed that posting. However over time the very lower portion of the tank will contain the dirtiest fuel if the crud is held in suspension.
Mike.

 

[Daffy64]

That'll teach me, speed reading, I missed that posting. However over time the very lower portion of the tank will contain the dirtiest fuel if the crud is held in suspension.
Mike.

The fuel, water and crud is very well mixed as it is agitated when a vehicle is being driven, partly through motion and partly through the return to the tank, you’ll find that most of it gets to the filter, the picture in post #80 would be after standing for for a period.

If a vehicle is being used and fuel is being drawn from somewhere that has a turnover then the crud in the fuel tank should be moving towards the filters and remain trapped there or go through the engine.

Thats not to say that blocked filters are a good thing but the average fuel tank system is actually very clean and to a point self cleaning.

 

[VXman]

Yes, we always check our route to see if there's a Costco fuel station en-route. Premium diesel at lower price than the lowest regular we can find elsewhere. Reading seems particularly cheap !

I assume you need to be a member at Costco to buy fuel there?

 

[akadingbat]

Back in the days when I was a tugger my Navara needed a new DPF and Nissan were quoting £3500 just for the new DPF then labour on top. A dear friend and mechanic recommended a commercial mechanic who got me and after market DPF with a lifetime guarantee on it for £300. Had it fitted and no problems. So for anyone needing a new DPF out of warranty then try a local independent commercial mechanic.

 

[Clive Beeza]

Never bought a litre of posh diesel or Redex for either 12 year old car or 11 year motorhome. Nigh on always supermarket fuel.

Stopped using supermarket fuels years ago
when I learnt that at tanker fillings at the refineries
the same % additives as top petrol station brands
are reduced for the supermarket stations deliveries
and I treat the fuel twice a year to cat-a clean diesel additive
runs like a dream

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