Diagnostic Procedure
You can easily locate and repair most oil leaks by visually finding
the leak and replacing or repairing the necessary parts. Some fluid leaks,
however, are difficult to locate or repair. The following procedure can help
you locate and repair most leaks.
Finding the Leak
Do the following to locate a leak:
- Identify the fluid. Determine if the fluid is engine oil, automatic
transmission fluid, power steering fluid, or other fluids.
- Determine where the leak is. When the vehicle reaches normal operating
temperature, park the vehicle over a large sheet of paper. After a few minutes,
you should be able to find the approximate place of the leak from the drippings
on the paper.
- Visually check around the suspected component. Check for leaks
around all gasket mating surfaces. Use a mirror to find leaks that are hard
to reach.
- If you still cannot find the leak, clean the suspected area with
a degreaser, steam, or spray solvent. Dry the area. Operate the vehicle for
several miles at normal operating temperature, varying the speeds. After operating
the vehicle, visually check the suspected component. If you still cannot locate
the leak, use the powder method or the black light and dye method.
Powder Method
Perform the powder method as follows:
- Clean the suspected area.
- Apply an aerosol-type powder (such as foot powder) to the area.
- Operate the vehicle normally.
- Visually inspect the suspected component. You should be able to
trace the leak path over the powder surface to the source of the leak.
Black Light and Dye Method
A dye and light kit is available for finding leaks. Refer to the manufacturer's
directions when using the kit.
- Pour the specified amount of dye into the leaking component.
- Operate the vehicle normally, as directed.
- Direct the light toward the suspected area. The dyed fluid appears
as a yellow path leading to the source of the leak.
Repairing the Leak
Once the leak is identified and traced back to the source, determine
the cause of the leak. Repair the leak properly. If you replace a gasket,
but the sealing flange is bent, the new gasket will not repair the leak. You
also must repair the bent flange. Before attempting to repair a leak, check
for the following:
Gasket Leaks
Check for the following conditions:
• | High fluid level or high oil pressure |
• | Plugged crankcase ventilation filter or PCV valve |
• | Improperly tightened fasteners or dirty/damaged threads |
• | Warped flanges or sealing surfaces |
• | Scratches, burrs, or other damage to the sealing surfaces |
• | Damaged or worn gaskets |
• | Cracking or porous components |
• | Improper sealant used or no sealant where required |
Seal Leaks
Check for the following conditions:
• | High fluid level or high oil pressure |
• | Plugged crankcase ventilation filter or PCV valve |
• | Damaged seal bore (scratched, burred, or nicked) |
• | Cracks in the component |
• | Shaft surface scratched, nicked, or damaged |
• | Loose or worn bearing that causes excessive seal wear. |