Tool Required

J 39400 Leak Detector

Most oil leaks are easily located by visual inspection and repaired by replacing and/or repairing the necessary parts.

Use the following steps in order to find the leak:

1. Identify the fluid. Determine whether it is engine oil, automatic transmission fluid, or power steering fluid.
2. From what point is the fluid leaking? After running the vehicle at normal operating temperature, park the vehicle over a large sheet of paper. After a few minutes, you should be able to find the approximate location of the leak by the drippings on the paper.
3. Visually check around the suspected component. Check around the gasket mating surfaces for leaks. A mirror is useful for finding leaks in hard-to-reach areas.
4. If the leak still cannot be found, it may be necessary to clean the suspected area with a degreaser, steam or spray solvent. Clean the area well, then dry the area. Operate the vehicle for several miles at normal operating temperature and varying speeds. After operating the vehicle, visually check the suspected component. If you still cannot locate the leak, try using the powder or black light-and-dye method.

Perform the following steps in order to use the black light-and-dye method:

1. Pour specified amount of dye into the leaking component system.
2. Operate the vehicle under normal operating conditions as directed by the J 39400 .
3. Direct the light toward the suspect area. The dyed fluid will appear as a yellow path leading to the source. See the J 39400 kit directions for the color of the fluid and the dye mix.

Perform the following steps in order to perform the 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 white powder surface to the source.

Once the origin of the leak has been pinpointed and traced back to its source, the cause of the leak must be determined in order for it to be repaired properly. If a gasket is replaced, but the sealing surface is damaged, the new gasket will not repair the leak. The surface must be repaired or replaced. Before attempting to repair a leak, be sure that the gasket and sealing surfaces are correct.

Perform the following steps in order to check for gasket leaks:

1. Inspect the fluid level/pressure to see if it is too high.
2. Check the crankcase ventilation system for restrictions or malfunctioning components.
3. Inspect for improperly tightened fasteners or dirty/damaged threads.
4. Look for warped flanges or sealing surfaces.
5. Check for scratches, burrs, or other damage to the sealing surface.
6. Look for a damaged or worn gasket.
7. Check for cracking or porosity of the component.
8. Check for use of an improper sealant used -- where applicable.

Perform the following steps in order to check for seal leaks:

1. Inspect the fluid level/pressure to see if it is too high.
2. Check the crankcase ventilation system for restrictions or malfunctioning components.
3. Check for a damaged O-ring seal bore--scratched, burred or nicked.
4. Look for a damaged or worn oil seal.
5. Check for improper component installation.
6. Look for cracks in the component.
7. Inspect the shaft surface for scratches, nicks, or damage.
8. Check for a loose or worn bearing which may lead to premature oil seal wear.