It's Here and its Not Good !


Under the EU's Renewable Fuel Transport Obligation, 5% of fuel in member states must come from renewable sources by 2014 This is to be in creased to 10% by 2020

This as meant that petrol suppliers have been adding ethanol to your unleaded fuel and indeed they are allowed to supply upto  10% ethanol (known as E10) now!!  Many are taking this route as adding ethanol adds more profit, AND gives less miles per gallon, so we have to buy more!!


Ethanol...what is it?

It is essentially an alcohol that is produced by formenting and distilling sugar or stach crops such as wheat, sugar beet and sugar cane ( yes just like moonshine!) It is the number one choise of fuel suppliers, as it burns reasonably well, although it isn't a hydrocarbon like petrol because it contains oxygen as well as hyrogen and carbon. This oxygen is both good and bad for the engine. Good because it helps to give a cleaner burn, but bad in that it assists corrosion in the fuel system. In 2010 the Department of transport estimated that up to 8.6 million vehicles may be incompatible with the new E10 fuel, more resent put the figure at 2.9 million, but either way a lot of AACNW members now have a problem

Lets take a look at some of these problems ethanol brings


Ethanol is hygrosopic, it attracts water and moisture from the air, it is also highly tempature dependant and can freeze in cold weather. Ethanol in fuel also causes “phase separation” when water is absorbed. So when just one drop of water over the limit is absorbed it can cause all of the water and ethanol to separate from the fuel,leaving an incombustible pool at the bottom of your tank or carb float bowl


Ethanol is acidic, which attacks metals, rubber and plastics in the fuel system Sealants on pipes, joints and gaskets can also be affected by the acidic ethanol leading to leaks and deposits moving through the system, blocking filters, jets and injectors Any water and the oxygen in ethanol will further accelerate this corrosion


Ethanol is not compatible with traditional detergents found in modern petrols. It destabilieses the petrol and increases its tendency to oxidise and degrade thus leaving deposits when combusted. These deosits can cause severe drivability problems like poor economy and hesitation as well as interrupting the fuel/air ratio

Loss of Economy

Ethanol will lower overall fuel comsumption for a number of reasons

1. Ethanol contaians less BTU's (British Therml Units) than petrol

2. The Ethanol's tendandency to absorb moisture lowers the energy value in combustion

3. If this moisture is suspended in the fuel at the time of purchase, you will have paided for water!

4. The tendancy to create deposits interferes with injector spray patterns and the fuel/air ratio

Excessive heat

Studies have identified higher burn temperatures with ethanol resulting in more carbon deposits, these deposits will interfere with the fuel/air flow within the engine affecting performance. Another consequence of these higher temperatures is that the oil will heat up more and may form some sludge and burn onto the surfaces of the engine. Piston rings and valves will also be subject to this “cooking”issue



So What Do We Do Now


First of all lets deal with the more modern engines (from around 2000 onwards)

Check with your owners manual for a fuel type recommendation, I'm betting that most of you will find that your manual will state that you are ok to run E10 ( petrol containing 10% ethanol ) or in some cases on later cars E15 (15% ethanol) as most US cars were built ethanol ready from around 2000 on Also try checking your fuel cap or fuel cap door as some are marked with E percentage information

So for most later modal cars, in theory you will be ok, as the european limit is E10 at the moment......BUT in the UK you still may have a problem ! The percentage of the ethanol in our fuel can change from garage to garage, depending on (a) how much is added to the tanker that refills the station and (b) how the fuel is stored at the station ( water entering the tank can cause the seperation of the ethanol out of the petrol)

I have made my own testing kit so I can test the ethanol percentage of petrol sold in my area and the findings have been surprising with values from zero up to 18%  in one of the latest tests! Details of how I made my own test kit can be found on my website, or try this link


Now lets look at the older,classic cars or cars not built to run a E percentage. Well basically,we are in trouble!

Ethanol is acidic, which will attack the metals, gaskets and rubber in the fuel system. Its also hygrosopic, it attracts water and moisture from the air which causes corroion in the system.

The most common problems that are found  when your older car is being attacked by ethanol are fuel feed problems (fuel pumps and blockages in fuel lines) and running problems (blocked carburetors and injectors)

With fuel feed problems, the fuel lines can be replaced with ethanol resistant piping and new pump    diaphragms have been developed that are ethanol safe. Most new parts from the States are safe to use but if you are buying NOS (New Old Stock) watch out!

To minimise running problems I suggest running a good quility inline filter immediately before your carbs, as most problems occur when jets etc become blocked with corroion particles released into the system, probably from the fuel tank or fuel pipes

But by far the biggest problem is with the hygrosopic properties of ethanol and the resulting corrosion of metals. This can happen very quickly (see the attached picture) and be very costly to repair. To avoid or reduce this happening you can do a few things.

1. Keep your car running over the winter monthes, this will keep the fuel moving and reduce  chances of corrosion setting in.

2. Don't let water or moisture enter the system (vented fuel caps can be totally sealed if the car is not being used

3. Petrol mixed with ethanol has a shorter shelf life and goes stale quickly,so smaller more frequent fill ups

4. Use  more modern or new petrol stations as these are better than older or village stations, because they have better filter systems  and are less likely to allow water or moisture to enter their tanks

5. Use a fuel stabilizer or additive designed for fuels with ethanol. These additives are added to your fuel and coat the interal surfaces protecting them from oxidation. But make sure that these additives are safe to use with other additives you maybe using. (using a octane booster can accelerate the detrimental effects of ethanol) Millers Oils do choise of three additives One for ethanol protection only, one for ethanol and lead replacement and one for ethanol protection, lead replacement and octane boost

6. Change any paper based fuel filters to ethanol safe filters

7. Replace norml rubber fuel pipes with ethanol safe pipes