Is Your Classic Car E10 Ready?

The internet is awash with scary stories about how the E10 fuel rollout could damage your cherished vehicle, especially if it was made before the millennium. We’ve studied the science and squeezed out the real-life actions you can take to help you make your Classic Car E10 ready.

E10 fuel is being introduced now because of the Renewable Transport Fuel Obligation. This came into place in 2005 and was initially a requirement made of all transport fuel suppliers to ensure they were supplying at least 5% of all their vehicle fuel from a renewable source by 2010, which has now increased further to 10% of all vehicle fuel by 2021.  

By adding ethanol to petrol, the combustion burns slightly cleaner, which in turn reduces the greenhouse gases produced by vehicles. The expectation in the UK is a saving of 750,000 tons going into the atmosphere. This is the equivalent of 350,000 vehicles being removed from the roads or a 2% reduction in carbon dioxide per exhaust tailpipe. 

E10 fuel is a biofuel that is made from 90% unleaded petrol and 10% Ethanol.

Ethanol is an organic chemical compound made by refining sugar cane and grains and classified as renewable. To meet with the Renewable Transport Fuel Obligation, fuel manufacturers have mixed petrol with ethanol by 5 or 10%, hence the E5 and E10 moniker.

The classic car community is so concerned because Ethanol is alcohol and it dries out rubber fuel pipes and components, leading to perishing, cracking, and potentially fuel leaking too. 

It is also hygroscopic, meaning it absorbs moisture, which could cause serious issues when it comes to being left in storage. For example, in your fuel tank over winter as the fuel can separate out into an Ethanol/water mix in the bottom, and a heavier end fuel part in the top. When the temperature drops the water separates out from the ethanol and you get just water in the bottom – this happens in the tank and also in the carburettors. It is banned for use in Aircraft due to the problems it creates.

The lower calorific value and oxygen contained in E10 fuel means your engine might run leaner. The higher volatility is good for injection under pressure, but with a low-pressure system and a bit of heat soak, you could get vapour lock in the fuel lines in the engine bay which could lead to problems with hot starting.

Another factor that is worrying enthusiasts, is that Ethanol is a solvent. Its presence is likely to loosen a lot of the gum coating from old fuel in tanks, and combined with rust, will cause blockages in fuel filters and pipework. 

Since 2011 all new cars have had to be produced to work with E10 fuel. Because of this, the manufacturers have carefully specified the components within the fuel system to cope. But we don’t all drive ‘new cars’…

The RAC estimate 634,000 cars on the UK roads won’t be compatible, and 150,000 of those were made after 2000. This leaves almost half a million (484,000) vehicles many of which are of classic and modern classic status that just aren’t designed to run on this new mixture.

Unlike pouring petrol in a diesel motor, a tank or two of E10 fuel isn’t going to render your older car or camper useless. It will however increase the chances of a nasty things happening. The ethanol (the E bit) in E10 is present in a higher percentage now, which means its appetite for eating rubber, plastic and metal will be greater. Here’s what you can do.

According to the UK Government website, 95% of all petrol-powered cars on the road can use E10 fuel, and all vehicles made after 2011 should be fine. They have an E10 compatability checklist you can use, but it only covers vehicles from the mid-nineties onwards from what we can see. If you can't find your vehicle on the list, then you'll need to do one of the following. 

1. Use E10 fuel along with an additive. We'll explain more about that below. 

2. Use E10 and convert all parts on your vehicle to be ethanol safe, including fuel pipes and hoses. 

3. Use E5 Super Unleaded which only has 5% ethanol content.

There are a few additives being marketed, aimed at owners of older cars wanting to protect their vehicles from the E10 rollout. We’re not experts on this, but they allegedly work by altering the molecular structure of the ethanol within the fuel, inhibiting its ability to corrode your fuel pipes and tank, but importantly not removing the cleaner combustion benefits. At around £10 per bottle, per fill up, it will still feel a little lumpy but should keep things in good condition, if the label is to be believed. 

With E10 taking the place of regular unleaded on the forecourt, you’ll be looking towards the higher octane, and more expensive super unleaded options to continue to get an E5 fix for your classic car.

Whilst the ethanol content is lower, the octane rating (RON number) is higher. Performance cars such as the Mk2 Golf GTI or a Porsche 911 might have this as the recommended fuel, however it is going to make very little difference to the performance or economy of the average older car.  

At the risk of sounding like a stuck record, there are several precautionary measures you should take to keep your classic car safe, regardless of whether you choose to use E10 or E5 fuel.

The first is to renew all your fuel hoses with those designed to work with Ethanol fuels. 

The second is to carry a fire extinguisher or install an automated fire suppression system, should the worst happen whilst out on the road. Read our guide to fire extinguishers here. 

I hope this article has helped to explain and answer the questions you may have surrounding the roll out of E10 fuel. Further reading can be found on the UK Government website.

Happy motoring.

Andy