After an extensive consultation process, the
Department for Transport has introduced
legislation to mandate E10 petrol as the standard
95-octane petrol grade from 1 September 2021
and in Northern Ireland, this will happen in early 2022. They will also require the higher-octane
97+ ‘Super’ grades to remain E5 to provide
protection for owners of older vehicles. This
product will be designated as the ‘Protection’
grade. The change in fuel applies to petrol only.
Diesel fuel will not be changing.
Petrol pumps now show new labels designating
the grade, the maximum ethanol content and an
advisory cautionary notice. Other information
regarding the introduction of E10 petrol may
also be provided by fuel retailers such as the
‘Know your Fuel’ sticker (shown at the foot of this
article).
For some time, service station pumps have
had E5 and B7 labels consistent with the BS
EN16942 standard that has been adopted across
Europe. This standard also sets out the labelling
requirements for other renewable fuel grades
such as E85, B20, B30, etc. that can be found
across Europe either on service station forecourts
or for captive fleet use.
At the filling station
At the petrol station, a circular ‘E10’ or ‘E5’
label will be clearly visible on both the petrol
dispenser and nozzle, making it easy
for you to identify the correct petrol
to use together with the warning
text “Suitable for most petrol vehicles: check
before use”
The ‘E10’ and ‘E5’ labels look like this:
Labels on modern vehicles
New vehicles manufactured from 2019 onwards
should have an ‘E10’ and ‘E5’ label close to the
filler cap showing the fuel(s) they can use.
What fuel should I use?
Almost all (95%) petrol-powered vehicles on the
road today can use E10 petrol and all cars built
since 2011 were required to be compatible.
If your petrol vehicle or equipment is not
compatible with E10 fuel, you will still be able
to use E5 by purchasing the ‘super’ grade (97+
octane) petrol from most filling stations.
Our recommendation
The Federation recommends that all vehicles
produced before 2000 and some vehicles
from the early 2000s that are considered noncompatible with E10 – should use the Super E5
Protection grade where the Ethanol content is
limited to a maximum of 5%.
To check compatibility of vehicles produced since
2000, we recommend using the new online E10
compatibility checker however, please note that
many manufacturers are missing and there are
some discrepancies regarding particular models.
Additional information on vehicle compatibility
issues is available on the FBHVC website.
What is ethanol?
Ethanol is an alcohol derived from plants,
including sugar beet and wheat. Increasingly,
waste products such as wood are also being
used to manufacture ethanol. Therefore, it is
renewable and not derived from fossil fuels.
Why are we using it?
Principally ethanol is being added to fuel in
order to reduce carbon emissions as Britain
heads towards its target of net zero emissions by

According to Government experts, this will
reduce greenhouse gases by 750,000 tonnes per
year which, they say, is the equivalent output of
350,000 cars.

The move will bring the UK in line with many
European countries which have been using
E10 fuels for a number of years already. In some
parts of the world, such as South America much
higher levels of bioethanol have been in use
since as early as the 1970s.
What might happen?
1 Corrosion / Tarnishing of metal components
2 Elastomer compatibility – swelling, shrinking
and cracking of elastomers (seals and flexible
pipes) and other unsuitable gasket materials
3 Air/fuel ratio enleanment
Some historic vehicles use materials in the
fuel systems that are damaged by ethanol.
These include some cork, shellac, epoxy resins,
nylon, polyurethane and glass-fibre reinforced
polyesters. In later cars these have largely been
replaced with paper gaskets, Teflon, polyethylene
and polypropylene which are all unaffected by
ethanol. Very old leather gaskets and seals are
also resistant to ethanol.
As the ethanol molecule is smaller and more
polar than conventional petrol components,
there is a lower energy barrier for ethanol to
diffuse into elastomer materials. When exposed
to petrol/ethanol blends these materials will
swell and soften, resulting in a weakening of
the elastomer structure. On drying out they can
shrink and crack resulting in fuel leaks.
If your fuel system has old hoses or any
degradation of components, then ethanol may
appear to advance these problems very quickly.
You may experience leaks or fuel “sweating” from
fuel lines. Some fuel tank repair coatings have
been found to breakdown and clog fuel systems,
although there are plenty of ethanol resistant
products on the market.
What can we do?
The most important thing is to ensure your fuel
system components are regularly inspected
and renewed as part of a routine maintenance
programme for your historic vehicles. Ultimately
owners should look to renew fuel system
components such as hoses, seals and gaskets
with ethanol safe versions as a long – term
solution and more of these are entering the
market through specialists every day.
If you should decide to make the necessary
vehicle fuel system modifications together with
the addition of an aftermarket additive to operate
your classic or historic vehicle on E10 petrol. The
FBHVC strongly recommends that you regularly
check the condition of the vehicle fuel system
for elastomer and gasket material deterioration
and metallic components such as fuel tanks, fuel
lines and carburettors for corrosion. Some plastic
components such as carburettor floats and fuel
filter housings may be become discoloured over
time. Plastic carburettor float buoyancy can also
be affected by ethanol and carburettors should
be checked to ensure that float levels are not
adversely affected causing flooding and fuel
leaks.
Ethanol is a good solvent and can remove
historic fuel system deposits from fuel tanks
and lines and it is advisable to check fuel filters
regularly after the switch to E10 petrol as they
may become blocked or restricted. If your vehicle
is to be laid up for an extended period of time, it
is recommended that the E10 petrol be replaced
with ethanol free petrol which is available from
some fuel suppliers. Do not leave fuel systems
dry when storing, as this can result corrosion and
the shrinking and cracking of elastomers and
gaskets as they dry out.
Engine tuning
Ethanol contains approximately 35% oxygen by
weight and will therefore result in fuel mixture
enleanment when blended into petrol. Petrol
containing 10% ethanol for example, would
result in a mixture-leaning effect equivalent
to approximately 2.6%, which may be felt as
a power loss, driveability issues (hesitations,
flat spots, stalling), but also could contribute
to slightly hotter running. Adjusting mixture
strength (enrichment) to counter this problem
is advised to maintain performance, driveability
and protect the engine from overheating and
knock at high loads.
Modern 3-way catalyst equipped vehicles do not
require mixture adjustment to operate on E10
petrol because they are equipped with oxygen
(lambda) sensors that detect lean operation and
the engine management system automatically
corrects the fuel mixture for optimum catalyst
and vehicle operation.
Additives and vehicle storage.
Ethanol has increased acidity, conductivity and
inorganic chloride content when compared to
conventional petrol which is typically pH neutral.
Ethanol can cause corrosion and tarnishing of
metal components under certain conditions.
These characteristics are controlled in the
ethanol used to blend E5 and E10 European and
UK petrol by the ethanol fuel specification BS
EN15376 in order to help limit corrosion.
Some aftermarket ethanol compatibility
additives claim complete protection for
operating historic and classic vehicles on E10
petrol. The FBHVC is not aware of, or has tested
any additives that claim complete fuel system
protection with respect to elastomer and
gasket materials for use with E10 petrol. The
FBHVC therefore recommends that elastomer
and gasket materials are replaced with ethanol
compatible materials before operation on E10
petrol.
However, corrosion inhibitor additives can be
very effective in controlling ethanol derived
corrosion and are recommended to be added
to ethanol in the BS EN15376 standard. It is
not clear if corrosion inhibitors are universally
added to ethanol for E5 and E10 blending so
as an additional precaution it is recommended
that aftermarket corrosion inhibitor additives are
added to E5 and E10 petrol.
These aftermarket ethanol corrosion inhibitor
additives often called ethanol compatibility
additives are usually combined with a metallic
valve recession additive (VSR) and sometimes an
octane booster and have been found to provide
good protection against metal corrosion in
historic and classic vehicle fuel systems.
What happens if I fill up with E10
by accident?
Don’t panic – your car will continue to run,
just fill up with E5 at the next opportunity and
avoid storing your vehicle for long periods with
E10 fuel.
E5 Petrol
E5 petrol can contain between 0 and 5% by
volume ethanol. Other oxygenated blend
components may also be used up to a maximum
petrol oxygen content of 2.7%. There is a variation
at the pumps, not just between brands but also
between different areas of the country, some will
contain a lot less but the absolute maximum is
capped at 5%.
E10 Petrol
E10 petrol contains between 5.5 – 10%
ethanol by volume. Other oxygenated blend
components may also be used up to a maximum
petrol oxygen content of 3.7%. Again, there is a
variation at the pumps, not just between brands
but also between different areas of the country,
some will contain a lot less but the absolute
maximum is capped at 10%.

It should be noted that some Super E5 Protection
grade fuels do not contain Ethanol as the E5
designation is for fuels containing up to 5%
Ethanol. To re-iterate, product availability varies
by manufacturer and geographical location.
Diesel labelling
The renewable content of diesel fuel will not
be changing and service station fuel pumps
will continue to be labelled as B7, designating a
biodiesel, Fatty Acid Methyl Ester (FAME) content
of between 0 and 7% by volume. New vehicles
manufactured from 2019 onwards should have a
‘B7’ and or higher content label close to the filler
cap showing the fuel they can use.
The ‘B7’ label looks like this:
For media enquiries, please contact:
Wayne Scott at Classic Heritage PR,
07759 260899
wayne@classicheritagepr.co.uk
About the FBHVC:
The Federation of British Historic Vehicle Clubs
exists to uphold the freedom to use historic
vehicles on the road. It does this by representing
the interests of owners of such vehicles to
politicians, government officials, and legislators
both in the UK and (through the Federation
Internationale des Vehicules Anciens) in Europe.
There are over 500 subscriber organisations
representing a total membership of over 250,000
in addition to individual and trade supporters.
All our directors operate in a voluntary capacity
supported by our secretary.
Website: www.fbhvc.co.uk