Biodiesel - Longer Term Verdict - brambob

Following my previous posts on this subject I am now in a position to give a longer term view, having covered about 3000 miles on a 100% biodiesel, supplied by ID Oils near York.


1999 Mercedes C220 CDI


There appeared to be no material difference in performance - if anything the power/acceleration seems to be a little smoother with less evidence of the turbo surge when accelerating.

Fuel Consumption

Fuel Consumption overall was less good than with normal diesel. The fall-off was around 8% even though a handout from the suppliers of the fuel claimed that fuel consumption would improve by about 7%.


65.9 pence per litre, obviously quite a bit cheaper than normal fuels. The suppliers claim that because of EU tax proposals the price of Biodiesel could reduce by another 20 pence per litre over the next two years.


The other main benefit was the smell from the exhaust which was much more pleasant than normal diesel fumes.


The major drawback was that with the Biodiesel the car seemed to start hesitantly from cold, as if suffering fuel starvation. On occasions the engine would splutter and die three or four times before running normally. Once it got going it was fine. As I was away on holiday last week and could not obtain Biodiesel I had to put ordinary diesel in, and I have found that this problem has now disappeared.


I am a bit unsure about using Biodiesel all the time because of the starting issue as discussed above but I will probably continue with perhaps alternate fills for the foreseeable future.

Biodiesel - Longer Term Verdict - andymc {P}
Hi brambob,
I'm a long term biodiesel user too, so any time I see a posting referring to it I can't stay away! My Leon has just passed the 28k mark, which has mostly been on 100% biodiesel - the only time there would be derv in the tank is if I run out of bd, so I conservatively estimate that this car has done 25k on biodiesel. I've posted elsewhere about experience with other cars (BMW 525 TD, Renault Clio dci, VW Passat TDi), but I estimate my total mileage on this fuel over the past 2 years has been in excess of 50k.

I notice more power in the Seat, and noticed a bit more in the BMW. Any differences with the Clio and the Passat were negligible - this surprises me a little, as the Passat has the same 110 bhp car as the Leon, but maybe it's just that the Leon is lighter and two years younger.

I've always experienced a slight improvement in fuel consumption, whichever car I was using. To be honest though, this was a pleasant surprise, as I have repeatedly encountered predictions that an approximate 5% reduction in mpg would be likely. My supplier even warned me of this at the outset, and I would have thought that all suppliers should mention this. Perhaps my experience is fortunate because my supplier is one of the leading proponents of biodiesel in Europe, so he sure knows how to make good stuff!

The price I pay is 75p a litre, all duty paid, so you're doing very well at 65.9.

With regard to the starting issue - Do you know whether your supplier is using fresh or recycled vegetable oil to make his fuel? Do you know what kind of oil he is using, ie sunflower, rape, canola, etc? Different oils lead to fuels with slightly different properties. For an extreme example, think of the difference in colour and viscosity between grapeseed oil and palm oil - the latter is solid at comparitively high temperatures, so is too viscous at most ambient temperatures in our climate. Fuel derived from rape or sunflower should be fine, though.
Another possibility is that there may have been a certain amount of sludge at the bottom of your tank from 4 years of using derv - this is perfectly normal. However, if this is the case then putting biodiesel in the tank for the first time tends to clean all this out, and it usually ends up deposited on the fuel filter. Changing back over to derv may have had the effect of dissolving the build-up, I'm not sure. It may be worth checking your fuel filter and, if it's dirty, changing it. Ask your supplier, if they know their stuff they should be able to advise. You could also post on the biodiesel forum, located at
... someone on there may be able to suggest other possibilities.
The fuel I use has given me no problem with starting either the Leon or the Clio at 10 degrees below freezing the winter before last. It is made from used cooking oil.
Biodiesel - Longer Term Verdict - andymc {P}
PS should have mentioned that I acquired my BMW at 98k miles, and after the first 1200 miles or so of running on biodiesel I noticed a gradual reduction of power, as though the engine wasn't getting enough fuel. Had the car serviced, new fuel filter, problem disappeared - I reckon it was the sludge problem, but unfortunately never got to see the filter as the mechanic's mate burned it!
Biodiesel - Longer Term Verdict - brambob


Looks like you and I are the only ones interested in this subject!

Thanks for your words of wisdom.You are clearly highly knowledgeable on the subject! Apparently the fuel is recycled vegetable oil, although they did tell me on one occasion when I filled up that they were experimenting with different blends. Apparently it was originally 95% oil and 5% other things (alcohol, I think they mentioned, among other things) but they said that they were looking to increase the oil content to 98%.

I will certainly ontinue to use it, although not perhaps exclusively. The starting problem seemed to get worse over a period of time so perhaps a fill of standard derv from time to time will prevent a recurrence.

The only other thought is whether the starting problem could get worse as winter and the cold weather approaches.

Thanks again

Biodiesel - Longer Term Verdict - Baskerville
Looks like you and I are the only ones interested in
this subject!

Not at all, but I don't live near a source of biodiesel so I have no experience of it. If I could buy it near here I definitely would.
Biodiesel - Longer Term Verdict - No Do$h
That's a point, I seem to remember there are some suppliers in the Fens. Must look them up next week when I'm back up there.

An Alfa, running on chip lard? That will be a talking point!
If I don't reply it's nowt personal, I'm just working!
Biodiesel - Longer Term Verdict - Soupytwist
Those in the more remote parts of East Anglia may be able to get Biodiesel from Broadland Fuels of Norfolk.

Their website says that they do mail order as well, I'm hoping to take advantage of that when I move house.

Matthew Kelly
No, not that one.
Biodiesel - Longer Term Verdict - andymc {P}
ChrisR, just in case you don't have these links, you can check
Between those two sites, there are over 110 UK suppliers listed, so there's an outside possibility there may be one not too far away. Many outlets only sell a 5% blend, but it's better than nothing.

Brambob, I have to admit that the only biodiesel blends I've heard of in this country are blends with derv, in varying percentages from 5% to 95%. I have heard of "winterising" products being used in other parts of the world, like Canada or some northern states of the US, but that's where you're getting down to 30 below in winter and ordinary engine oil can freeze. Without going into too much technical detail, you might want to ask whether your supplier's fuel is "washed" or not, and if so what method they use - bubble washing (air coming up from the bottom, like an aquarium) or mist washing (a very fine spray of water gradually taking the final impurities, soaps etc to the bottom of the container). Unwashed fuel could be another possible cause for the rough starting.

I haven't come across putting alcohol in biodiesel for burning as fuel - methanol is used to produce biodiesel, but the reaction must be as complete as possible and my understanding has always been that there should be NO alcohol left in the end product. Cylinders and injectors could both be at risk if there is any unreacted methanol left in the fuel. It's more likely that your supplier was talking about 5% derv.

The only other possible cause for rough starting I can think of (apart from what I've mentioned already) could be that the recycled oil may contain trace elements of palm oil, which is often used to part fry things like chips before they are frozen. If traces of this are present in the used cooking oil before it is turned into biodiesel, it means that small amounts of what my supplier calls "palmitics" could be in the fuel. Although the individual particles are small enough to go through a 5 micron filter, these tend to clump together when cold and so can cause clogging. However, a mild blend of derv - between 5% and 10% - is enough to keep these particles in solution, eliminating the problem. This shouldn't be an issue in summertime though.

Why not print out this page and take it to your supplier - it may help to eliminate possibilities. There shouldn't be any reason why you can't run on biodiesel all the time.

PS I was staying just outside York last month - whereabouts are you?
Biodiesel - Longer Term Verdict - Sooty Tailpipes
I have used almost exclusively ASDA refined rapeseed oil with 10% white spirit (as a dispersant) for 20,000 miles in a 1998 BMW-powered Omega. I believe its OK to call this biodiesel, as it is a CI fuel of biomass origin.

I am 100% pleased with the results, the car starts first revolution, the power seems better lower down, ie WOT from a standing start (its an auto), the same power higher up. my mpg can be as high as 49mpg on a long A-road run, and is around 28mpg semi-congested urban. I can't really comare the mpf with dino, as I have used so little!

When I have to put dinodiesel in because I'm caught short or its too bad weather to pour vegoil out of bottles, the engine is more dieselly and not as refined.

I have noticed, that for some reason I can't think what, if I run diesel and open the throttle fully from a standstill (automatic) it black smokes a bit, it also does this with vegoil, yet if I mix them, there is no smoke AT ALL!!?
I change the fuel filter every 10000 miles and do oil services every 4000 miles as a precaution.
Biodiesel - Longer Term Verdict - guss
i would love to use biodiesel in my tdi golf but am watching with interest to a report of large numbers of vw pd engine failures in germany whilst running on biodiesel. it seems to be only in germany so is probably limited to bad quality fuel in that country only. with biodiesel why isnt the government making its benefits more known as the advantages to uk farmers and the environment could be great. perhaps additional tax incentives similar to lpg to make it more attractive
Biodiesel - Longer Term Verdict - Sooty Tailpipes
Men with big noses are surpressing biofuels.
The government hates biofuels.
Biodiesel - Longer Term Verdict - teabelly
The mass use of biofuels would lead to serious revenue reductions as there is no way you can justify taxing a 'clean' fuel in the same way as you would ordinary petrol and diesel. I think this is why the government are so clean to get congestion charging up and running as they can see the massive revenue stream disappearing into a haze of biodiesel fumes.

Biodiesel - Longer Term Verdict - googolplex
Forgive me, I haven't really been following all of the Biodiesel debate but I'm a bit put off by the cost versus risk factor. Andy states above that he is paying about 75p per litre which is only 2p less than the shell garage up the road. Balance that against unknown risk: to what extent has biodiesel been researched as a fuel for modern diesel cars? If brambob's car is hesitant at start up that is, for me, rather ominous! Also, there seems to be some variation in the source of fuels. I'm not reading anything here which makes me want to go through the hassle of changing.
Biodiesel - Longer Term Verdict - CMark {P}
Also see previous long and interesting BR threads on this:

"Top Gear and cooking oil" at

and Andy's "First fill of Biodiesel"
Biodiesel - Longer Term Verdict - jeds
I would like to go bio but I have a 3 month old Passat and I have heard that the Volkswagon PD system has caused problems in German cars using biodiesel. I'm also not confident about the warranty situation. As Splodgeface says, the small benefit seems a bit too risky at the moment.
Biodiesel - Longer Term Verdict - andymc {P}
"I have used almost exclusively ASDA refined rapeseed oil with 10% white spirit (as a dispersant) for 20,000 miles in a 1998 BMW-powered Omega. I believe its OK to call this biodiesel, as it is a CI fuel of biomass origin."
Well joosisigu, it's certainly a biofuel, but being pedantic it isn't true biodiesel - your fuel is vegetable oil thinned with white spirit that remains in the end product and goes into your tank, whereas biodiesel is vegetable oil which has undergone a catalysed chemical reaction. They are still physically similar, but chemically they are different. Not that I'm saying you shouldn't use it or anything! I'm sure you're aware of potential coking issues using unreacted vegoil, so I won't go into that now.

"i would love to use biodiesel in my tdi golf but am watching with interest to a report of large numbers of vw pd engine failures in germany whilst running on biodiesel. it seems to be only in germany so is probably limited to bad quality fuel in that country only."
guss, I have to be honest and admit that I hadn't heard of any biodiesel-specific problems with PD engines, although I have heard of PD engines being problematical in themselves. I'd be grateful if you could point me towards any information about this - I'm genuinely interested.

"I'm a bit put off by the cost versus risk factor ... to what extent has biodiesel been researched as a fuel for modern diesel cars? "
Not being facetious here, but the original diesel engine was designed to run on peanut oil! But there have been significant amounts of research done in the US - particularly by the University of Idaho and Europe into the viability of biodiesel and it is a well proven fuel. I can dig out some links for you if you like, although it'll probably be tomorrow before I get round to it.

"Also, there seems to be some variation in the source of fuels."
This is true, but only because there are many types of vegetable oil (how many can you name!), and they can all be turned into biodiesel. Even animal fat can be turned into biodiesel, although again it would not be suitable for our cooler climate. Also, the fact that biodiesel can be made from either used oil or fresh oil means that there are different processing methods, each suitable for whichever oil is used as a feedstock. I would also argue that one encounters an equally diverse range of fossil fuels at the pump - eg the great supermarket vs branded fuel debate. But whatever the source oil, whether fresh or used, all biodiesel should be produced to the EN14214 standard, which has been criticised for being TOO stringent.

"I'm also not confident about the warranty situation."
All diesel-engined VAG cars (ie VW, Seat, Audi, Skoda) are warranted to use 100% biodiesel - check your handbook, it'll specify the standard. As the EN14214 standard is new, your handbook (like mine) may mention the now-superseded DIN 51606 standard instead.

One of the benefits of using biodiesel is that it is much more lubricating than derv - this means your engine will last longer!
Biodiesel - Longer Term Verdict - kevin babij
Kenlowe engine block preheater might be a worthy investment if your a regular winter user.
The truckers swear by them for approved cold starting,fuel ecomony and a nice warm cabin in the morning.
I believe the truckers have a habit of adding a splash of petrol to the tank to prevent waxing?

Value my car