Magazines:  Real Estate Shopping: Adult Costumes  |  Kids Costumes  |  Car Books  |  Guitars |  Electronics
This Issue Archived Articles Blog About Us Contact Us

Use of Ethanol-Blended Fuels

Things to know

Courtesy I-Car

Click on pics to view larger images

This material first appeared in the I-CAR Advantage Online, which is published and distributed free of charge. I-CAR, the Inter-Industry Conference on Auto Collision Repair, is a not-for-profit international training organization that researches and develops quality technical education programs related to collision repair. To learn more about I-CAR, and to subscribe to the free publication, visit

Vehicles have evolved from the limited design models 100 years ago to the many unique colours, shapes, sizes, and brands available today. Along with allowing the consumer the option of selecting the vehicle maker, model, trim level, two-wheel, four-wheel, or all-wheel drive, they also can select from either gasoline, diesel, compressed natural gas, gasoline-electric, or flex-fuel to determine which propulsion system they may want.

With these many options available to the consumer, there are also opportunities for a repair facility to become exposed to different types of vehicle fuel systems. The two most recent fuel system introductions are the gasoline-electric hybrid and vehicles capable of burning ethanol-blended fuels, E85 being the most common.

There are different types of ethanol-blended fuels, and it is important for repair technicians to know the differences and what can go wrong when servicing vehicles with ethanol-blended fuel.

Ethanol is an alcohol derived from corn and is used, in general, for two basic reasons: economics and to reduce pollutants introduced into the environment. Ethanol is mixed with fuel in three common formula ratios, though depending on your location in the world, the common ratios can be different.

Fuel Ratios

Click for larger image

Fuel ratios are expressed in the mixture of ethanol to gasoline, with the letter “E” and a number. The number indicates the percent of ethanol in the fuel mixture.

E10, which is a mixture of 10% ethanol and 90% gasoline, can be used in internal combustion engines of most modern vehicles. E10 is available in North America and along with E85, is the only type of gasoline sold in Minnesota. As of the spring of 2006, due to the phasing out of methyl tertiary butyl ether (MTBE), which was used as a gasoline additive in the place of lead, E10 has become very common throughout North America.

Similar blends to E10 include E5 and E7, which are generally safe for engines that normally run on pure gasoline. Some regions mandate that locally sold fuels contain at least some ethanol. It is in this situation where these smaller ratio fuels may be sold.

E15 (15% ethanol/85% gasoline) is generally the highest ratio of ethanol to gasoline that is recommended by vehicle makers selling vehicles in North America in vehicles that do not carry the designation of E85 or flex-fuel.

E20 (20% ethanol/80% gasoline) is not yet widely used in North America, but will be mandated by Minnesota for all gasoline sold by 2013. Since February 2006, E20 is the required mixture for all gasoline sold in Brazil.

Click for larger image

E85 (85% ethanol/15% gasoline) is generally the highest ethanol fuel mixture found in the U.S. It is common in Sweden, and is gaining in popularity across North America.

E95 contains just 5% gasoline and is used in some diesel engines where high compression is used to ignite the fuel, as opposed to the operation of gasoline engines where spark plugs are used. This is because as octane ratings increase, compression ratios must also increase to cause the fuel to ignite.

E100 is straight ethanol used in Brazil and Argentina. Ignition in temperatures below 15°C (59°F) causes problems when using pure or neat ethanol. A common cold-weather solution is adding a small gasoline reservoir to increase the gasoline content momentarily so ignition can occur and the engine can start. Once started, the engine can be operated on pure ethanol. In Brazil, ethanol fuel is hydrated ethyl alcohol, which is a mixture of 96% ethanol and 4% water. This distillation creates the purest form of ethanol.

To clearly know which vehicles are designed to operate on which types of fuel, refer to the vehicle owner’s manual, fuel fill cap, signage on the vehicle, or vehicle maker’s service information.

Flex-Fuel Vehicles

As of 2006, almost every vehicle maker has a flex-fuel, or E85-capable, vehicle for sale in North America. As an example, for 2006, General Motors vehicles equipped with a 5300 V8 engine are designed as flex-fuel vehicles.


Regardless of the vehicle maker, the use of ethanol-blended fuels can cause driveability issues from using ethanol-based fuels with ethanol concentrations above 10% in non flex-fuel vehicles, or from a condition called “phase separation.” Phase separation occurs when water saturation occurs to ethanol-blended fuel.

Using fuel in vehicles that are not capable of handling ethanol ratios above 10% can damage parts from the fuel pump to the engine. Depending on the age of the vehicle and the vehicle maker, flex-fuel-specific parts can include the fuel tank, fuel pump, fuel sending unit, non-metallic fuel lines and hoses, fuel filter, fuel injectors, and parts of the exhaust system.

Phase Separation

Click for larger image

When water is absorbed by the ethanol, the alcohol in the fuel begins to be removed, therefore lowering the octane rating of the fuel. When enough moisture is absorbed into ethanol-based fuels (one gallon of ethanol fuel can absorb 3.8 teaspoons of water), the fuel can no longer absorb water and the extra water separates and settles to the bottom of the fuel tank.

What occurs as a result are poor driving conditions, such as knocking, pinging, sluggish performance, or a hard or no-start condition. From the effect of the alcohol being removed, the air-to-fuel ratio becomes lean and combustion chamber temperatures increase. Increased combustion chamber temperatures will lead to premature wear.

With ethanol fuels being used more in North America, the opportunity for water entering an open fuel system may become a concern for repair facilities. Water contamination of a fuel system may become a problem for vehicles that are stored for extended periods of time in environmental conditions that are humid or wet.


With the ever-changing design of motor fuels, and the evolution of vehicles that are capable of burning different types of fuel, there could be a diagnostic challenge for repair facilities today and in the future. Filling a vehicle with the wrong fuel can lead to driveability problems not commonly seen by most technicians.

Did you enjoy this article?

Please consider supporting AutoSpeed with a small contribution. More Info...

Share this Article: 

More of our most popular articles.
Assessing the performance of an amazing human powered vehicle

DIY Tech Features - 15 January, 2008

Air 150 Recumbent Trike, Part 2

The story behind the Datsun 240Z

Special Features - 16 July, 2008

The First Zed

What's happened to electronic advances in cars?

Special Features - 19 May, 2009

Car Electronics Going Nowhere?

Easy, cheap and effective

DIY Tech Features - 30 April, 2013

Building a home sound amplifier, Part 1

Finding the best place to put an engine cold air intake

DIY Tech Features - 10 July, 2001

Siting Cold Air Intakes

How Ford in the US is developing safety systems - it's very weird!

Special Features - 29 September, 2009

Water-Blasting Cannons and Shopping Trolleys...

A brilliant new temperature controller that's so cheap it's unbelievable.

DIY Tech Features - 15 November, 2011

$25 Temperature Controller and Display!

Sand moulds to cast aluminium

Technical Features - 25 November, 2008

Metal Casting, Part 2

Getting planning approval

DIY Tech Features - 7 February, 2012

A New Home Workshop, Part 3

Testing performance

DIY Tech Features - 21 April, 2009

Ultimate DIY Automotive Modification Tool-Kit, Part 4

Copyright © 1996-2019 Web Publications Pty Limited. All Rights ReservedRSS|Privacy policy|Advertise
Consulting Services: Magento Experts|Technologies : Magento Extensions|ReadytoShip