David Lock

Biofuel bacteria wrecks engines | Auto Express News | News | Auto Express


I doubt if it's as bad as they say but worth noting, especially if you fill up from a dinky little low turnover garage.

Personally I think growing crops for cars instead of humans is a disgrace aside from some out of way locations where bringing in fossil fuel is not practical. dl

johnnyroper

bio diesel also eats yellow metals like brass and will wax up at warmer temps than conventional diesel.

sillysi

The report says that the diesel filter clogs up and the engine then cuts out and leads to a huge repair bill. This happens on our land rovers run on veg oil, the simple remedy is to change the filter every 3 months or so then the problem never occurs. Not sure what the huge repair bill would be?

David Lock

Yeah I wondered that

I expect one motorist once needed a new fuel pump.. once.... which was nothing to do with a clogged filter.

I like the bit about checking for excess water in the tanks. When I pay £1.20 per litre I don't expect to be paying for added water

dl

Luminous

iTrader: (3)

Can the engine lean out and cause lots of internal damage if the fuel flow is reduced (I know that can happen with petrol)

phil_wrx

iTrader: (2)

been running our tesco distribution vehicles on bio fuel for a long time and never heard of one case like this?

Shark Man

LOL @ the bacteria claim

Normal crude oil diesel suffers bacteria problesm (known as the "diesel bug" )

Claims say its erradicated, by use of various additives...I say BS...as our steam cleaner has it - it runs on normal pump diesel - always has done. But the filters clog up on a monthly basis, with what is best described as a mould type growth. Depite the whole thing being drained and flushed out - its comes back. Seems once bacteria is in the system it is very very difficult to erradicate it without replacing every surface the fuel comes into contact with (i.e tank, lines, pump, filters, injector etc).

Red diesel is also probalmatic in terms of quality control (no doubt down to way its supplied and stored) - which is why so many boat owners have running issues associated with clogged filters and contaminated tanks.

Petrol is not without problems either - stations with low throughput suffer water contamination. Which explains my water contamination issues when buying Optimax (a minority fuel when compared to 95RON).

Shark Man

No its not quite like that: A diesel ALWAYS runs lean. Engine output is controlled by regulating fuel flow. Essentially a diesel is always running at full throttle (no airflow restriction) all of the time...just the fuel flow is restricted. In comparison a petrol engine primarily ristricts airflow to restrict output (one reason why turbos work so much better on diesels).

However, with dodgy fuel, what can cause engine damage is from it creating poor fuel atomisation and leaky injectors.

Injectors "mist" fuel, like that of can of hair spray. A clogged injector or low line pressure feeding it will cause it to "squirt" instead of spray. Or leak and dribble fuel. This leads to poor combustion.

Most of the time this causes power loss and smoke. With modern diesels, the particulate filter may become overwhelmed, causing a restriction in the exhaust and will need to be replaced or reconditioned.

In the worst case a piston will melt. As poorly atomised fuel droplets burn too close or on the actual piston surface. Usually the melted piston ends up with a hole in it...this hole pressurises the crankcase. This causes oil mist to be pushed out the crankcase into the oil breathers, which leads to the inlet manifold. So oil enters the combustion chamber and burns. Now the engine runs off its own oil. It cannot be controlled, or turned off. It will run until it runs out of oil and seizes (or blows up) or if the driver has the intitiative to stall it by dumping the clutch in 5th gear with the foot on the brakes.

This is what is known as a "run away" diesel....when it runs away...you run away, as you don't want to be anywhere near it when it starts to self destruct

stevie boy

alot of bio diesel comes from used cooking oil.

stevie

David Lock

There are two "biodiesels" really. The home grown veggie oil which could include filtered chip fat and is prepared at home but with a conversion kit for the engine. The main thing would be warming the veggie oil as it's too viscous when cool, and possibly changing the fuel pump.

The other biodiesel is when the rape seed oil or whatever is processed (esterification) with some quite hairy chemicals to make it very similar in character to regular diesel. This can be done at home if you know what you are doing and don't mind blowing up the garage if it goes wrong. This is the stuff that, by law, must be added to pump fuel at 2.5% mix (to increase over time) and most diesels should be fine with this and won't need modifying. There are some questions about using it in old diesels because the bio can corrode old rubber fuel pipes.

Like I said earlier IMHO the whole thing is ill thought through. My mate uses veggie oil and it works well in a td Mitsubishi. I think you are supposed to declare what you use for tax reasons but his memory is terrible.......

dl

vindaloo

re the tax declaration. They've changed the rules. You can now make up to 2500 litres of the stuff for personal use without penalty.

HM Revenue & Customs: Follow up to Revenue & Customs Brief 37/07 on Biofuels Simplification

J.

David Lock

Thanks. Methinks they are going to miss out on a lot of revenue. So say my pal buys a 25 litre drum of oil at the supermarket he might just forget to write that down somewhere...... And he does a lot of miles per year. dl

plantpotman

.. as little as 1% normal derv added to pure bio should be sufficiently toxic to retard any mould growth ?? .. but I know of at least 1 fleet of vans that suffered no end of fuel pump / injector problems when running this stuff "neat" .. been OK since occasional normal derv added occasionally .. apart from the inconvieniance of breakdown a more serious implication is that it might not get fixed under warranty !

Diesel

Call me sad but I found that fascinating!

There is NO WAY I'm putting chip fat through my Diesel - the injectors are £300 a pop x 6. It's more worth me lining the Chancellor's pocket!

D