GM Service Manual Online
For 1990-2009 cars only

Most fluid leaks can be located and repaired by visually finding the leak and replacing or repairing the necessary parts. The following procedures may aid in finding leaks.

Locating the Leak

  1. Identify the fluid, determine whether it is engine oil, transaxle fluid, power steering fluid, etc.
  2. At what point is the fluid leaking from? After running the vehicle a minimum of 24 km (15 miles) to reach operating temperature, park the vehicle over a large sheet of paper. The drippings on the paper should indicate the approximate location of the leak.
  3. Visually check around the suspected component. Check around all gasket mating surfaces for leaks. A mirror may be helpful inspecting components that are hard to see.
  4. If a leak still cannot be found perform the following:
  5. 4.1. Clean suspected area with a degreaser, steam, or spray solvent. Clean and dry the area well.
    4.2. Operate the vehicle at normal operating temperature and vary speeds for several miles.
    4.3. After operating the vehicle, inspect the suspected component. If the leak still cannot be found, try the powder or black and dye method.

Powder Method

  1. Clean the suspected area.
  2. Apply an aerosol-type powder, such as foot powder, to the suspected area.
  3. Operate the vehicle under normal operating conditions.
  4. Visually inspect the suspected component. You should be able to trace the leak path over the powder to the leak.

Black Light and Dye Method

A dye and black light kit is available for finding leaks. Refer to the manufacturer's directions when using the kit.

  1. Pour the specified amount of dye into the leaking component.
  2. Operate the vehicle under normal operating conditions.
  3. Direct the light toward the suspected component. The dyed fluid will appear as a brightly colored path leading back to the leak.

Repairing the Leak

Once the leak has been pinpointed, the cause of the leak must be determined in order to repair the leak. Before attempting to repair a leak, check to be sure none of the following conditions are present.

Gaskets

    • Fluid level/pressure is too high
    • Plugged vent or drain-back holes
    • Improperly torqued fasteners or dirty/damaged threads
    • Warped flanges or sealing surfaces
    • Damaged or worn gasket
    • Cracking or porosity of the component

Seals

    • Fluid level/pressure too high
    • Plugged vent or drain-back holes
    • Damaged or seal bore (scratched, burred, nicked)
    • Damaged or worn seal
    • Improper installation
    • Shaft seal surface scratched nicked or damaged
    • Cracks in component
    • Loose or worn bearing causing excess seal wear

Possible Points of Oil Leakage

    • Shift control housing assembly:
       - Attaching bolts not correctly torqued
       - Improperly installed or damaged gasket
    • Case leak:
       - Axle seals worn or damaged
       - Porous casting
       - Filter seal damaged
       - Sensor loose or damaged O-ring