Red Diesel-Vegetable Oils.


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Vegetable Oils.  Seed oils are not particularly "good" for most modern diesels, in fact they can be downright destructive for most common rail set-ups. Seed oils contain no lubricity agents.  Bosch EDC pumps, in common with the Lucas pumps, fuel and hence lubrication is cut off to the rotorhead during conditions of overrun (engine braking).  Any restriction in fuel supply to the pump, for instance a partial filter blockage could also cause damage to the pump, through lubrication starvation.  Early models were quite prone to failing, within the distributor rotor assembly, which has been through three different updates since the pump was first made. Later pumps are therefore more reliable in this respect. Seed oils also adsorb water from the atmosphere and as a consequence, there is a greater risk of problems in cold weather due to waxing.  They tend to have a higher viscosity than DERV and need to be passed thru a pre-heater, prior to being fed thru a calibrated diesel injection pump (Ford Endura DE-Di engines have a nice modular inline heater fitted to them).  HM C&E will check high mileage commercial vehicles for seed oil.  It is a simple matter to check, all that is required is a hygrometer.  All UK DERV is Ultra Low Sulphur Diesel (ULSD) and is formulated with a very tight specific gravity tolerance at the refinery. If the SG does not match what it should be on the list they carry, you're nicked.  They also can check recorded mileages from VOSA computer for private cars.  So beware of high mileage private use, above the 2500lts allowed.

Red diesel.  One other word of warning.  If anyone is thinking of buying "cheap" diesel, don't bother. It is more than likely rebated or red diesel that has had the dye stripped out.  Forget all those fanciful tales of pouring it through fuller's earth to remove the dye, it's just not true.  What they actually use is Oleum (fuming sulphuric acid) & cat litter (the active ingredient contained in it, that neutralises the smell of cat urine also does wonders at removing dye), lime or cement powder, then filter it again thru cotton wool or a one micron industrial steam filter.  This not only strips the dye but also all of the lubricity agents and all the other additives that are added to DERV, anti-wax & anti-foam.  The resultant toxic sludge is then dumped at the side of the road, with all the resulting environmental impacts.  Oh... and because red diesel has a different SG to DERV, the hygrometer trick still works equally as well.  Most HM C&E roadside testing (dipping) used to be done with a clear squeegee bottle and a pipe, they would simply take a sample from your tank, look at the colour, either nick you on the spot or put it back in the tank and let you go on your way.  But now they have very neat, small portable mini labs to test your DERV at the roadside.  Kerosene (28sec oil) is commercial/home heating oil which is known as 'kero' or 'paraffin'.  It is straw/orange in colour, very clean burning (has a very low sulphur content) and economical to use, however it contains no lubricant and is thus not suitable as fuel for engines.  Even when mixed 50/50 with DERV,  HM C&E roadside checks can still detect it, using their new high-tech mini labs. 

Some people fit a second "hidden tank" so they can use red derv undetected.  Carefully routing the supply/return pipes out of view.  Only to be caught because the HM C&E have dipped there main tank and its been green derv they have pulled out, reason being if derv stands about it absorbs water "hygroscopic" then if left for a long while green-blackish microbes grows in it.  HM C&E staff are dipping cars & light vans all day & if they can't get a pipe down your fuel filler tube, alarm bells will ring.

Red diesel in a un-tampered state, will not harm a road going engine, most damage to pumps related to running on red diesel is caused by water or other contaminants being mixed with the fuel.  The source normally can be traced back to dirty fuel containers/cans being used to store & transport the fuel.  We have over the years removed some vile looking fluids from fuel tanks over the years!  Red diesel stripped of its dye & additives will wax in cold weather, foam causing problems filling small auto fuel tanks and may wreck injection pumps due to the removal of lubricity agents.

Red diesel will be history in the next few years, the Goverment will just insist everybody buys white roadfuel, and if you can prove a legitimate reason for claiming the extra duty back, i.e. farming or fishing.  You will get it.  Pleasure boats are now not allowed to use red diesel.  I wonder if I can buy bulk quantities of taxed diesel in, claim I am running a diesel heater in my workshop and use the fuel in my car.  They can't be that stupid, can they...  You can do the same with LPG bought for central heating now if you want to de-fraud the exchequer.

LPG is the only viable cheap fuel at the moment, that is until the Government raises the tax on it.  I never think they will.  As it is used for domestic heating, it has a lower VAT & duty rating.  HM C&E staff can't sample a car gas tank easily, they just are never going to be able to regulate it.  Someone somewhere will be having gas delivered for there house boiler at a cheaper price & pumping into their car as a fluid, using industrial forklift filling equipment & pump.  A point of interest is: in Europe, adapters are available to refill 13kg 19kg 49kg propane bottles via auto-gas-pumps, its not a cheaper way of buying the gas than exchanging empty for full bottles.  Cost wise its only worth refilling small bottles.

LPG kits are always a headache to commission after installation.  Faultfinding on cars fitted with kits by other installers is even a bigger headache. 

It is possible to install a LPG kit on a diesel engine, it works by adding small amounts of LPG to the charge of diesel in the cylinder.  Unless you have a fleet Volvo F12 juggernauts doing sub 10mpg and 1500miles a week, these conversions are not worth considering.

Biofuels.  I have joined a forum and been following it with great interest.  Everybody on there seems to either have great success or monster problems.  All I see at work is damged pumps, injectors and engines.  Blocked fuel systems.  Big repair bills.  The truth is, despite what anybody says about the subject, the technology is in its infancy.  My advice is, if you are going to have a play, is to buy a very low cost car to play with.  This has not put me off the subject, I intend to follow the subject a bit more before I have a dabble.

Diesel & water emulsions.  Elf and Lubrizol have plans to sell diesel & water emulsions under the trade names "Aquazole" and "Purinox" respectively for use in closed commercial fleets.  As far as is known these emulsions have been tested only with inline fuel injection systems not rota diesel pumps.  The rumour in the trade is, Bosch are being very quiet about the issue.  The advantages quoted about by the fuel companies being;  emissions can be immediately reduced for a limited period without having to take any other measures.  My initial thoughts were, water is cheap!  The disadvantage is, diesel & water emulsion fuel is, its not suitable for more modern fuel injection systems.  For that reason, the fuel cannot be sold on the open market.  Diesel & water emulsion fuels have loads of additives such as, emulsifiers, anti-corrosive additives, anti-freeze, lubricant and biocides to prevent the growth of micro-organisms. 

I suspect the big fuel companies will be very quiet over new fuels.  As its coming to light now, pre 1998 low sulphur diesel did not have enough lubricant in it and was the cause of wear related problems on distributor type fuel injection pumps, which are lubricated by fuel.  They have raised the lubricity value of EN590 fuel to 460um to correct this.  Bosch recommends the use of diesel fuel with a lubricity value no less than 400um.  Diesel now contains silicon additive, to upgrade the lubricity value.  In early 2005 an oil refinery in Essex added this by mistake to a batch of petrol.  Tescos unknowingly sold the fuel, collateral damage was to include hundreds of customers petrol engined CATS and O2 sensors had to be replaced.  Tesco footed the bill, the oil refinery denied liability initially.

Early EDC pumps are known to fail from "cavitation" due to an ingress of water.  Water separates out from the fuel over time in diesel filters, and if the filter housing is not drained down at intervals.  The water will damage the pump beyond repair.  Most car manufacturers are now fitting new type water level sensors to filter housings on new models.  Supermarket fuel is jokingly called emulsion in the trade, as it has such a high water content.  It maybe cheap for a reason! 

Diesel particulate filters.  DPF type filters don't like anything with a high content of sulphur in it.  Sulphur affects the regeneration process.  So only good clean Derv in vehicles equipped with DPF filters.

LPG Auto-Gas conversions

Page updated 28-05-18