E5 vs E10 Petrol: Why We Recommend E5 for Classic Cars

You pull into the petrol station. E10 is cheaper. E5 costs a little more.

Does it really matter which one goes into your classic?

We think it does.

At Weaver Car Storage, we look after everything from modern performance cars to classics that may spend weeks or months at a time in storage. When it comes to older petrol vehicles, our preference is E5 Super Unleaded wherever it is suitable for the vehicle.

What’s the difference between E5 and E10?

The main difference is ethanol content. E10 petrol can contain up to 10% ethanol, while E5 contains up to 5%.

For a modern vehicle designed to run on E10, this generally isn’t a problem. But classic and older vehicles can be a very different story.

Why can E10 be a problem for classics?

Ethanol can attract and absorb moisture. This is particularly important with vehicles that aren’t being driven regularly and may have fuel sitting in the tank for longer periods.

Over time, higher ethanol content can also be harder on some older fuel system components, including certain rubber hoses, seals, gaskets and other materials that weren’t originally designed with modern ethanol blended fuels in mind.

The result can be deterioration, corrosion and, in the worst cases, fuel leaks.

A small saving at the pump suddenly doesn’t look quite as attractive if you’re replacing parts of a classic fuel system.

Storage makes fuel choice even more important

A daily driven car is constantly using and replacing its fuel. A stored classic might be sitting with the same fuel for weeks or months.

That’s why we take fuel seriously at Weaver Car Storage.

Before storing a classic or older petrol vehicle for an extended period, it’s worth considering what’s actually in the tank. Where the manufacturer permits it, we’d generally choose E5 Super Unleaded over E10.

It’s a simple precaution that can help reduce the potential problems associated with higher ethanol content, particularly during longer periods of inactivity.

Don’t forget the rest of the fuel system

Fuel choice is only part of looking after a classic.

Older fuel hoses and connections should be regularly inspected for cracking, deterioration, dampness or the smell of petrol. If something doesn’t look right, don’t ignore it.

A leaking fuel line isn’t just an expensive problem. It’s a serious fire risk.

Is E5 right for every car?

Always check the requirements for your individual vehicle. Some classics may require additional considerations depending on their age, engine, fuel system and any modifications made over the years.

But for many of the classic and cherished petrol vehicles we look after, E5 is our preferred choice wherever suitable.

Our view

Classic cars were built to be enjoyed, but they also need looking after differently from modern vehicles.

Using the right fuel, keeping an eye on ageing fuel components and thinking about what happens while the vehicle is sitting unused can make a real difference.

E5 might cost a little more at the pump, but when you’re protecting a classic car, we think it’s money well spent.