Service Bulletin

Bulletin No.: 03-06-01-023I
Date: December, 2024

INFORMATION
Subject:

Higher Than Expected Oil Consumption at 8600 GVW and Above

Models:

2020–2025 Chevrolet Silverado 2500HD/3500HD with 6.6L RPO (L8T)
2000–2025 Chevrolet Silverado, 2500/3500
2000–2019 Suburban
2016–2025 Chevrolet Low Cab Forward Trucks
2000–2025 Chevrolet Express
2002–2013 Chevrolet Avalanche
2003–2010 Chevrolet Kodiak C4500-C5500 Series Models
2020–2025 GMC Sierra 2500HD/3500HD 6.6L RPO (L8T)
2000–2019 GMC Sierra, 2500/3500
2000–2019 Yukon XL
2000–2025 GMC Savana
2003–2010 GMC TopKick C4500-C5500 Series Models
2003–2010 HUMMER H2
with Gasoline Engine and Rated at 8600 GVW and above

This bulletin has been revised to Update the Measurement of Oil Consumption section.
Please discard Corporate Bulletin Number 03-06-01-023H.
Important: Service agents must comply with all International, Federal, State, Provincial, and/or Local laws
applicable to the activities it performs under this bulletin, including but not limited to handling, deploying,
preparing, classifying, packaging, marking, labeling, and shipping dangerous goods. In the event of a
conflict between the procedures set forth in this bulletin and the laws that apply to your dealership, you
must follow those applicable laws.

Information on Engine Oil Consumption Guidelines
All engines require oil to lubricate and protect the load bearing and internal moving parts from wear including
cylinder walls, pistons, and piston rings. When a piston moves down its cylinder, a thin film of oil is left on the
cylinder wall. During the combustion process, part of this oil layer is consumed. As a result, varying rates of oil
consumption are accepted as normal in all engines.

Oil Consumption
Oil usage has a direct relationship with the amount of fuel used. The harder an engine works, the more fuel and oil it
will use. Therefore, oil usage as a factor of fuel usage is a more accurate indicator of acceptable oil consumption
levels than vehicle mileage for vehicles at or above 8600 GVW.
The accepted rate of oil consumption for gasoline engines in vehicles at or above 8600 GVW is 1 liter (1 qt) within
400 liters (100 gallons) of fuel used. This rate only applies to vehicles under warranty, maintained in accordance with
the appropriate maintenance schedule, driven at legal speeds and within design intent of the vehicle.
Many factors can affect an owner's concern with oil consumption. Driving habits and vehicle maintenance vary from
owner to owner. Thoroughly evaluate each case before deciding whether the vehicle in question has abnormal
engine oil consumption.

Copyright 2024 General Motors. All Rights Reserved.

Page 2

December, 2024

Bulletin No.: 03-06-01-023I

Gasket and External Leaks
Inspect the oil pans, engine covers, and the engine oil cooler for leakage. Inspect for oil leakage into the engine
coolant.

Improper Reading of the Oil Level Indicator (Dipstick)
The vehicle must be parked on a level surface to obtain accurate oil level readings. Verify that the dipstick tube is
fully seated in the block. When checking the oil level, make sure the dipstick is wiped clean before taking an oil level
reading and fully depress the dipstick until the shoulder bottoms out on the dipstick tube. The dipstick should be the
proper part number for the engine/vehicle that is being checked.

Not Waiting Long Enough After Running Engine to Check Oil Level
The vehicle should be allowed to sit for at least 15 minutes, after the engine has been shut off, before taking an oil
level reading to assure the oil has had enough time to drain back into the crankcase. In order to ensure accurate
results, the temperature of the oil should be close to the same temperature as the last time the oil level was
checked.

Improper Oil Fill After an Oil Change
Following an oil change, verify that the proper amount and type of oil was put in the engine and that the oil level on
the dipstick is not above the full mark or below the add marks. Refer to the Owner's Manual or Service Manual for
information on recommended oil quantity, viscosity, and quality.

High Speed or High RPM Driving
Continuous driving at high speeds/high RPMs may increase oil consumption. Because this may not always be an
everyday occurrence, it is hard to determine exactly how much the oil economy will be affected.

Towing or Heavy Usage
Towing a trailer or hauling additional weight will increase oil consumption. Large frontal area trailers will further
increase the work required from the engine, especially at highway speeds, and thus increases the rate of oil
consumption.

PTO Operation
Operation of a PTO will increase fuel and oil usage, as the PTO driven accessory uses engine power to operate.

Crankcase Ventilation System
Verify that the positive crankcase ventilation (PCV) system is operating properly. Blockages, restrictions, or damage
to the PCV system can result in increased oil use.

Oil Dilution from Condensation
On vehicles that are usually driven short distances, less than 8 km (5 mi), especially in colder weather, condensation
generated from cold engine operation may not get hot enough to evaporate out of the oil. When this occurs, the
dipstick may indicate that the oil level is over-full. Subsequent driving on a trip of sufficient length to enable normal
engine operating temperature for 30 minutes or more, in order to vaporize excess moisture, may give the customer
the impression of excessive oil consumption.

Engine Temperature
If an engine is run at overheated temperatures (see Owner's Manual or Service Manual) for more than brief periods,
oil will oxidize at a faster than normal rate. In addition, gaskets may distort, piston rings may stick, and excessive
wear may result. Verify that all cooling system components are in proper working order.

Engine Wear
Piston scuffing, excessive piston-to-wall clearance, tapered or out of round cylinders, worn, damaged or improperly
installed valve guides, seals and piston rings will all cause an increase in oil consumption.

Measurement of Oil Consumption
Engines require a period of time to BREAK IN so that moving parts are properly seated. Therefore, oil economy
should not be tested until the vehicle has accumulated at least 6400 km (4000 mi). An exception would be allowed
only if an engine is reported to be using more than 0.946 liter (1 qt) in 1600 km (1000 mi).

Bulletin No.: 03-06-01-023I

December, 2024

Page 3

1. Verify that the engine has no external leaks. Repair as necessary.
2. Verify that the engine is at normal operating temperature (see Owner's Manual or Service Manual).
3. Park the vehicle on a level surface.
4. Wait at least 15 minutes, after the engine is shut off, before checking the oil level to make sure that most of the
oil has had time to drain back into the crankcase.
5. Check the oil level and record the vehicle mileage, date, and exact oil level on the form included in this bulletin.
Next ensure the oil level is at, but not above, the full mark on the dipstick. add oil if necessary. Also ensure the
proper viscosity and quality oil are being used as recommended in the Owner Manual
6. Ask the customer once they have consumed 100 gallons of fuel schedule an appointment and return to the
dealer for inspection.
7. If the final evaluation shows that the engine uses more than 0.946 liter (1 qt) in 379 liters (100 gallons) of fuel
used, follow the published symptom diagnostics as described in the appropriate Service Manual. If the oil
consumption test shows that the engine uses less than 0.946 liter (1 qt) in 379 liters (100 gallons) of fuel used,
explain to the customer that their engine meets the guidelines for oil consumption.

Oil Consumption Worksheet
Date
Dealer Name
Technician Name
Customer Name
Phone Number
VIN
Oil Typed Used
TAC Case #

Step

Date

Mileage

Oil Level

Engine Hours

Fuel Quantity
Used

Inspection Step

1

(Initial Visit
Inspection)
Please also note
mileage from
previous oil
service whether
done at dealer or
outside facility.

2

(Start of Test)

3

(2000 Mile
Inspection)

Page 4

December, 2024

Bulletin No.: 03-06-01-023I

Calculation:
System

Oil Used

/

Fuel Used

=

Qt/Gal or L/L

*

=

Oil Consumption
Qt/100 Gal
L/379L

Example

*

100

=

English

2Qts.

/
/

130

=
=

0.015

*

100

=

Metric

/

=

*

379

=

1.5 Qts.

Oil consumption of 0.946L/379L of fuel (1 qt./100 gal.) or less is considered acceptable.

Warranty Information
For vehicles repaired under the Powertrain coverage, use the following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH) for coverage information.
Labor Operation

Description

Labor Time

0600334*

Oil Consumption Test

0.5 hr

*This is a unique Labor Operation for Bulletin use only.

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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