Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Information Regarding The Differences Between Fluid Leakage And Seepage (15-00-89-004G)
Reference number: 15-00-89-004G
Supersedes refnos: 15-00-89-004, 15-00-89-004A, 15-00-89-004B, 15-00-89-004C, 15-00-89-004D, 15-00-89-004E, 15-00-89-004F
INFORMATION REGARDING THE DIFFERENCES BETWEEN FLUID LEAKAGE AND SEEPAGE
TECHNICAL SERVICE BULLETIN
| Affected Model(s): | 2025 and Prior GM Passenger Cars and Light/Medium Duty Trucks (including BrightDrop Models) |
| Attention: | This bulletin also applies to any of the above models that may be Export from North America vehicles. |
| Supercedes: | This bulletin has been revised to add the 2025 Model Year and BrightDrop Models. Please discard Corporate Bulletin Number 15-00-89-004F. |
SERVICE INFORMATION
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.
This bulletin is intended to help identify the differences between what is considered a fluid leak and what is considered seepage. Improper diagnosis may lead to unnecessary component replacement. Use the following information to determine if the condition is normal acceptable seepage or a defective component.
SEEPAGE
Seepage is defined as oil, film, or dust accumulation on the exterior of the component. When fluid droplets appear hanging from a component or fluid that has dripped to another component, see the section titled "Leakage" below.
Seepage is a normal condition and warranty does NOT cover the cost of repair attempts.
Examples:
The engine illustrated above shows residual oil staining from assembly. There are no drips or leak paths present.
You can see the darker area where fluid has attracted dirt. There are no droplets at the bottom of the seal area.
There is slight staining around the mount, but there are no droplets formed and fluid has not dripped onto other components.
The housing illustrated above just has a light coating of dirt; there is no sign of fluid. So this would also be considered seepage. A very small amount of fluid coated the outer surface of the housing and dirt was attracted to the moisture.
Seepage is Considered a Normal Condition
Any time a seal is used to hold back fluid on a moving component, some fluid will get past the seal over time. Even seals on lines that aren't moving can seep.
Vehicles are being subjected to large variations in temperature and vibrations that over time, may allow a small amount of fluid to be released.
Many new seals have a coating of grease to aid in installation. Once the seal is heated up during use, the grease can melt and leak out. Dirt will be attracted to the melted grease and it may appear that the seal has failed, but this is normal operation.
All lip seals that run directly on output shafts, axle shafts, transmission yokes, etc. have a grease pack between the sealing lip and the dust lip. This grease pack, over time will weep some oily residue past the dust lip. The dust lip is there to keep dust and grime away from the sealing lip, not to keep oil in. This is also considered normal operation.
If these seals are replaced, the new one will probably also seep over time as well.
LEAKAGE
Leakage is defined as fluid droplets hanging from a component or fluid that has dripped to another component.
Examples:
A droplet is formed on the end of the stud and the surrounding area is also covered with fluid.
This shock is also leaking. The surface of the shock housing is wet and droplets formed at the bottom and dripped onto the ground.
For more information on the diagnosis and replacement of shock absorbers, refer to the latest version of Service Bulletin 05-03-08-002: Information on Diagnosis and Replacement of Shock Absorber and Strut Due to Fluid Leak.
This is also a leak because there is a droplet formed on the bottom of the power steering line and fluid has dampened the drive axle.
This would also be considered a leak because fluid has coated the fitting and hose. Although there were no droplets hanging from the component, it's obvious that a reasonable volume of fluid has been lost and when we followed the line to its low point, we did find droplets there.
Once a leak is identified, determine the cause of the leak by performing the following steps:
- Operate the vehicle until the engine reaches normal operating temperature.
- Park the vehicle on a level surface, over a large sheet of paper or other clean surface.
- Wait 15 minutes.
- Inspect for drippings.
For more information on diagnosing oil leaks, refer to Oil Leak Diagnosis in SI.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.