Service Bulletin

Bulletin No.:
Date:

05-06-04-022Q
July, 2019

INFORMATION
Subject:

TOP TIER™ Detergent Gasoline and TOP TIER™ Diesel Fuel Information and Licensed
Brands

Models:

2020 and Prior GM Passenger Cars and Trucks (includes Medium Duty)
United States, Canada, Argentina, El Salvador, Guatemala, Honduras, Mexico, Panama
and Puerto Rico

This Bulletin has been revised to add Model Year 2020 vehicles, add countries with TOP
TIER™ fuel availability and remove the TOP TIER™ Licensed Retail Brands table. Please
discard Corporate Bulletin Number 05-06-04-022P.

TOP TIER™ Fuels – General Motors
Recommendation

3980710

3980709

Copyright 2019 General Motors LLC. All Rights Reserved.

Page 2

July, 2019
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4915798

Note: This is a voluntary program for fuel
marketers and not all fuel marketers will offer TOP
TIER™ Detergent Gasoline or TOP TIER™ Diesel
Fuel. Not all stations of a licensed brand may be
selling TOP TIER™ Diesel Fuel. Registration is
based on certification data and marketers of all
sizes including some major brands, independents
and big box stores.
•

A class of fuel called TOP TIER™ Detergent
Gasoline is available from various fuel marketers
for all octane grades of gasoline sold at their
stations in the United States (including US
Territories), Canada, Puerto Rico and certain
Central American countries. This gasoline meets
the detergent standards developed by eight
automotive companies. All vehicle engines will
benefit from using TOP TIER™ Detergent
Gasoline over gasoline containing the “Lowest
Additive Concentration” (LAC). LAC is also known
as the minimum detergent treat rate,
recommended by the Environmental Protection
Agency (EPA) in the United States and in Canada,
the Canadian General Standards Board (CGSB).
Those vehicles that have experienced engine
deposit related concerns may especially benefit
from using TOP TIER™ Detergent Gasoline.

•

•

Bulletin No.: 05-06-04-022Q
The TOP TIER™ program is not just about a high
detergency rate. It is a robust engine cleanliness
and performance specification validating the
specific chemistry within the detergent package.
TOP TIER™ Detergent Gasoline must conform to
the standards which specify that gasoline sold in
the selected nation or region shall not contain
metallic additives, including
methylcyclopentadienyl manganese tricarbonyl
(MMT). If a fuel marketer successfully completes
all of the engine and fuel injector testing required
in the TOP TIER™ specification, they can claim to
be TOP TIER™. All performance testing must be
conducted at an independent, ISO 17025
accredited laboratory.
A class of fuel called TOP TIER™ Diesel Fuel is
available from various fuel marketers. Since diesel
fuel retailers may also sell non-additized diesel
fuel or diesel fuel not meeting the TOP TIER™
requirements, always check the dispenser for
TOP TIER™ Diesel Fuel designation.
The EPA and CGSB require only a minimum
amount of detergent in gasoline. TOP TIER™
Detergent gasoline contains 2–3 times more
detergent than the EPA and CGSB minimum
requirement, resulting in a lower amount of intake
valve deposits (IVD). The IVD can negatively
affect fuel economy, emissions, and performance.
General Motors, FCA, BMW, Honda, Toyota,
Volkswagen, Audi and Mercedes-Benz developed
the TOP TIER™ Detergent Gasoline Standards
and support the use of TOP TIER™ Detergent
Gasoline by recommending it in their vehicle
Owner Manuals. All eight corporations recognize
the benefits to the engine, the environment, and
the consumer. Additionally, the companies
recognize that by joining together they can better
address the industry concern with low fuel
detergency levels and the intentional addition of
harmful organometallic additives. GM strongly
recommends the use of TOP TIER™ Detergent
Gasoline and TOP TIER™ Diesel Fuel.

A Cleaner Engine Has Performance and
Environmental Advantages
The following gasoline engine intake valve graphics
show the difference between an engine that did not use
TOP TIER™ Detergent Gasoline and an engine that did
use TOP TIER™ Detergent Gasoline at 16,093 km
(10,000 miles).

Bulletin No.: 05-06-04-022Q

July, 2019

Page 3

3979074

Engine intake valve using Non-TOP TIER™
Detergent Gasoline having the minimum detergent
treat rate with more than 1,000 mg of deposits.
Deposits (1 and 2) on the intake valve reduce fuel
economy by creating a porous surface that collects wet
fuel, thereby affecting the air to fuel mixture in the
cylinder and releases fuel late in the combustion cycle
leading to increased unburnt hydrocarbon (HC) and
carbon monoxide (CO) emissions. Likewise fuel
injectors may become restricted with carbon deposits
over time resulting in an incorrect injector spray pattern
and similarly increasing HC and CO emissions.

3979169

Engine intake valve using TOP TIER™ Detergent
Gasoline having a high detergent treat rate with
less than 50 mg deposits.
This intake valve is significantly cleaner, resulting in
optimal fuel economy and engine driveability
performance as well as reduced emissions.

TOP TIER™ Licensed Brands
The latest list of TOP TIER™ Detergent Gasoline and
TOP TIER™ Diesel Fuel Brands that have met the TOP
TIER™ standards will appear on the Home page under
the Licensed Brands tab. Use the drop down menu to
select Gasoline or Diesel. Visit this website:
https://www.toptiergas.com/
• Additional gasoline retailers are added to the TOP
TIER™ Licensed Brands list when they meet the
TOP TIER™ Detergent Gasoline standards.
• Additional diesel fuel retailers are added to the
TOP TIER™ Licensed Brands list when they meet
the TOP TIER™ Diesel Fuel standards.

Trademark Footnotes
TOP TIER™ Detergent Gasoline and its Logo are
Trademarks of General Motors LLC
TOP TIER™ Diesel Fuel and its Logo are
Trademarks of General Motors LLC

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
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 your GM dealer for information on whether your vehicle may benefit from the
information.

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