15-00-89-004A

Bulletin No.: 15-00-89-004A
Date: May-2015
Subject:
Information Regarding the Differences Between Leakage and Seepage
Models:
2016 and Prior GM Passenger Cars and Trucks
Attention:
This Bulletin also applies to any of the above models that may be Export vehicles.
This Bulletin has been revised to update the Leakage Information. Please discard Corporate Bulletin Number 15-00-89-004.
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.
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.
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This shock is also leaking. The surface of the shock housing is wet and droplets formed at the bottom and dripped onto the ground. Because this was a rear
shock and there are no other fluids in that area of the vehicle.
For more information on the diagnosis and replacement of shock absorbers, refer to the latest version of 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.
1.
Operate the vehicle until it reaches normal operating temperature.
2.
Park the vehicle on a level surface, over a large sheet of paper or other clean surface.
3.
Wait 15 minutes.
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4.
Inspect for drippings.
For more information on diagnosing oil leaks, refer to Oil Leak Diagnosis in SI.
Seepage
Seepage is defined as oil, film, or dust accumulation on the exterior of the component.
Important: 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.
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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.
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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