For 1990-2009 cars

# BLENDED FUELS INFORMATION

The attached copy of a recent GM publication outlines characteristics of the various blended fuels on the market today. It gives a brief history of blended fuel as well as some of the major disadvantages of methanol/gasoline blends, and a quick look at some of the regulatory considerations. Review of this publication by your sales and service organization should prove helpful in answering customers' questions concerning this very complex subject.

METHANOL/GASOLINE BLENDS POSE POTENTIAL PROBLEMS

Gasoline quality is an important factor in providing satisfactory engine and vehicle performance and fuel system life. Gasoline has traditionally been composed entirely of a mixture of hydrocarbons and its quality generally has been sufficient to prevent problems with vehicle perfomance and fuel system materials.

In recent years, however, the quality of some gasolines has changed. Economic and other factors have led suppliers to use alcohols as gasoline components. The first of these was ethanol (grain alcohol), which was popularized in gasoline under the name "Gasohol." Vehicle perfomance and fuel system durability with gasolines containing up to 10% ethanol, by volume, have generally been satisfactory.

More recently, methanol (wood alcohol), an alcohol with distinctly different properties than ethanol, has become a gasoline blending agent. The addition of methanol to gasoline for use in motor vehicles is receiving increased attention due to favorable economics, excess methanol production capacity, and the desire to reduce petroleum imports.

General Motors recognizes the favorable aspects of pure methanol as a future alternative fuel and certainly will produce cars that can use methanol if it becomes generally available. However, current use of methanol in gasoline can pose problems if used in today's cars over an extended period-even at low methanol concentrations in gasoline.

GM is concerned about the rapid increase in the use of methanol/gasoline blends in today's cars for two reasons:

There is no hard evidence on how much methanol can be blended with gasoline without adversely affecting vehicle operation and durability.

There is no adequate service station pump labeling system that will tell motorists the methanol content of the fuel they are purchasing.

There is limited information that suggests small amounts (up to around 5%) of methanol in gasoline may be suitable if a cosolvent-an ingredient that pre- vents the gasoline and methanol from separating when trace amounts of water are in the fuel-and a corrosion inhibitor to prevent damage to fuel system components are used. Evidence on the suitability of such blended fuels is incomplete and, therefore, their use cannot be endorsed by GM at this time.

It is likely some engines and fuel systems will be sensitive to methanol/gasoline blends that contain higher concentrations (greater than about 10%) of methanol- even if the fuels contain cosolvents and corrosion inhibitors. This sensitivity is generally related to compatibility with materials commonly used in vehicle fuel systems, such as fuel tank plating and certain rubber parts in carburetion systems. Also, driveability-performance of the vehicle-is adversely affected.

USE OF GASOLINE/ALCOHOL BLENDS EXPLAINED IN OWNERS' MANUALS

Owners of 1984 model GM automobiles are given specific information in their owners' manuals on what types of fuel may be used in their vehicles. On the subject of gasoline/alcohol blends, the manuals state:

Gasoline/Ethanol Blends

Blends of unleaded gasoline and ethanol (grain alcohol) sometimes known as gasohol are available in some areas. You may use these blends in your car, if they are no more than 10 percent ethanol, without jeopardizing the New Vehicle and Emission Warranties. Be sure the gasoline-ethanol blend has octane ratings no lower than those recommended for unleaded gasoline. Most drivers will not notice operating differences with blends of up to 10 percent ethanol, but some may. In that case, your dealer can make certain adjustments, provided they do not violate the Federal Emissions Standards. If you are still not satisfied with ethanol-gasoline blend performance, you may prefer to use unleaded gasoline.

Other Gasoline/Alcohol Blends

Some fuel suppliers sell gasoline containing alcohol without advertising the presence of alcohol or giving it a special name such as gasohol. If you are not sure whether there is alcohol in the gasoline you buy, check with the service station operator.

DO NOT USE gasolines containing methanol (methyl or wood alcohol) that do not also contain cosolvents and corrosion inhibitors for methanol. Also, DO NOT USE gasolines that contain more than 5 percent methanol even if they contain cosolvents and corrosion inhibitors. Fuel system damage or vehicle performance problems resulting from the use of such fuels is not the responsibility of General Motors and may not be covered under the new vehicle warranties.

Although gasolines containing 5 percent or less methanol and appropriate cosolvents and inhibitors for methanol may be suitable for use in your car, evidence of their suitability is as yet incomplete; therefore (GM Division) cannot, at this time, endorse their use.

GM is continuing to evaluate methanol/gasoline blends in both laboratory and vehicle tests to determine the effects of the blends on fuel system materials, engine deposits, driveability, emissions, and fuel economy.

There are economic advantages that encourage blending methanol with gaso- line. The average national tank price for unleaded gasoline sold to service station dealers (excluding taxes) in August was approximately 94 cents a gallon while methanol's cost was between 45-49 cents a gallon. On the other hand, ethanol cost $1.62-$1.80 per gallon. Ethanol/gasoline blends are competitive with gasoline only if a tax subsidy is allowed, but methanol/gasoline blends are not only competitive, they are enticing for the refiner, blender, and retailer.

The U.S. Environmental Protection Agency (EPA) has granted waivers, legally allowing the blending of methanol in gasoline. Waivers cover methanol con- centrations as high as 12%, as long as co-solvents are used. GM and other auto companies have not agreed with the EPA's decisions granting waivers for methanol/gasoline blends. The concern over use of methanol/gasoline blends has been heightened because illegally high levels of methanol have been found in some gasolines.

An EPA probe that began last spring in the Detroit area revealed illegally high levels of methanol in gasoline. Out of 250 samples of unleaded gasoline from about 150 service stations, about 8%-or 20 samples-had levels of methanol above those allowed by waivers, or did not contain cosolvents.

An investigation of nearly 400 service stations by the Michigan attorney general uncovered instances of methanol in concentrations of up to 15% in gasoline.

Because of concern over the compatibility of methanol/gasoline blends with current vehicle engines and fuel systems and illegal blending of methanol in gasoline, a number of states are planning to require that the methanol content of the fuel be posted on dispensing pumps. Although this is a step in the right direction, GM believes that motorists would be better served by a uniform labeling system nationwide. This would eliminate confusion caused by states adopting different labels.

#### HISTORICAL PERSPECTIVE

Alcohol/gasoline mixtures have been studied for more than 50 years. In the 1960s and early 1970s, the use of these blends was proposed (not always appropriately) as a way to reduce vehicle exhaust emissions and improve fuel economy. However, because the cost of alcohol was significantly higher than that of gasoline, the widespread use of alcohol/gasoline blends was not economically feasible.

Two significant actions of the past decade have renewed and expanded interest in alcohol/gasoline blends.

First, the severe interruptions of petroleum imports emphasized the need to increase production of domestic energy sources and reduce dependence on imported oil.

The production of alcohol fuels, particularly ethanol, became politically attractive in the late '70s at the height of the energy crisis. Its use was encouraged through tax subsidies. Commonly sold as Gasohol, it is now also marketed as "unleaded with ethanol," "super unleaded" or "premium unleaded" gasoline, depending on its octane level.

Also, during the recent recession, capacity for production of methanol from natural gas far exceeded demand. Methanol thus assumed a new attraction as a gasoline blending agent. The outlook for use of pure methanol as an auto- motive fuel is positive because the technical knowledge necessary to design and build methanol-fueled engines and vehicles is rapidly developing. In blends with gasoline, as stated earlie, methanol may not be suitable for use in either existing vehicles or future model year vehicles unless the vehicles are modified.

The second action which increased interest in alcohols as fuels was the reduction in the amount of lead anti-knock additives used in gasoline. This reduction, spurred by the EPA, occurred for two reasons:

The need for unleaded gasoline in cars equipped with catalytic converters.

The need to limit the emissions of lead into the atmosphere (by lowering permissible lead concentrations in leaded fuel).

Alcohols offer a means of replacing some of the octane (antiknock) quality previously provided by lead compounds.

MAJOR DISADVANTAGES OF METHANOL/GASOLINE BLENDS

There are a number of disadvantages associated with the use of methanol/ gasoline blends in vehicles designed for gasoline. Of major significance are:

DETERIORATION OF FUEL SYSTEM MATERIALS. Rubber, plastic, and metallic fuel system components in most vehicles were designed for use with gasoline, and may not provide satisfactory service with methanol/gasoline blends. Although few long-term durability tests have been run with blends, the results from a number of laboratory evaluations, as well as problems reported by motorists, make it clear that a variety of problems can occur. Most material problems are a function of time rather than distance travelled, so a 50,000-mile test completed in one year may not indicate what would happen during 50,000 miles of operation over four or five years. Components include fuel tanks, in-tank fuel pumps, carburetion and fuel injection systems, and nitrile rubber commonly used in vehicle fuel systems.

DRIVEABILITY Driveability is generally worse with methanol/gasoline blends than with gasoline alone. In hot weather, the generally higher volatility of the blends, compared with gasoline, causes a greater tendency toward vapor lock problems. Cold weather problems-stalling and hesitation-have been reported.

SEPARATION. The presence of even trace amounts of water in the fuel system may cause methanol/gasoline blends to become cloudy and separate into two layers, a gasoline layer on top and an alcohol/water layer on the bottom. A vehicle will not run satisfactorily on the alcohol/water mixture and corrosion of fuel system parts and deterioration of rubber parts can be greatly accelerated by contact with this mixture. Water tolerance of blends is increased by cosolvents, but even these do not completely eliminate the separation problem.

FUEL ECONOMY. In late-model cars, fuel economy (miles per gallon) generally decreases with the addition of methanol to gasoline. This is due to the lower energy content (per gallon) of methanol compared with gasoline. For example, a blend of 10% methanol in gasoline contains about 5% less energy per gallon than gasoline.

EVAPORATIVE EMISSIONS. Unless major changes are made in the distillation characteristics of gasoline, the addition of methanol to it significantly increases vapor pressure. This almost always results in a substantial increase in vehicle evaporative emissions.

REGULATORY CONSIDERATIONS

The regulatory aspects of methanol/gasoline blends are complex. The Clean Air Act prohibits the addition of additives to unleaded fuel, including methanol, unless the fuel additive manufacturer obtains a waiver from the EPA. In order to obtain such a waiver, the fuel additive manufacturer must show that the fuel will not cause-or contribute to-the failure of a vehicle or engine to meet the applicable emission standards for five years, or 50,000 miles.

The EPA has published guidelines that stress the need for development of data on possible methanol blending problems. GM supports the principles embodied in the guidelines, but believes it is important that EPA give careful consideration to potential problems when reviewing any fuel additive waiver application for alcohol/gasoline blends. During the last five years, a number of waivers have been granted.

GM and other automobile manufacturers are concerned that some of the blends approved by the EPA may be detrimental to vehicle emissions, performance, and components. Although several fuel suppliers have been successful in marketing methanol/gasoline blends, the long-term effects of the blends on vehicle durability are not yet known.

To assure customer satisfaction with its vehicles, GM is establishing a system to track reported vehicle problems to determine if methanol/gasoline blends are responsible for these problems.

If further investigation determines methanol/gasoline blends can be used in the existing fleet of vehicles without materials, driveability, or emissions problems, GM believes their use should be permitted. But only with adequate labeling of fuel at the pump will consumers be able to recognize the contents in the fuel they are purchasing.

SAFETY TIPS FROM GM

General Motors is pleased to see the latest report from the Highway Loss Data Institute which indicates that, overall, GM cars again beat all competition in the lowest frequency of accident injury claims. This year, HLDI finds that of the top ten cars with overall injury claim experience defined as "Substantially Better than Average," seven are GM cars.

GM believes this continued excellence (we've dominated the list for six years in a row) reflects not only our cars-their quality, size, weight, and design-but also how and where they are driven. The results show that our cars and customers go well together, and also emphasize our dedication to building quality and safety in our products.

But GM encourages drivers not to become complacent, as there obviously are still major roles for defensive driving techniques and self-protection.

The Public Relations Staff has prepared a new brochure "How To Avoid Or Help Survive A Car Accident"-which offers several tips from GM. It is part of a series on subjects of public interest.

If you would like a copy of this brochure, please contact the Public Relations Staff, Room 11-226, General Motors Building, Detroit.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.