GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Important: You can repair most fluid leaks by first visually locating the leak, repairing or replacing the component, or by resealing the gasket surface. Once the leak is identified, determine the cause of the leak. Repair the cause of the leak as well as the leak itself.

1

  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.
  4. Check for drippings.

Are drippings present?

Go to Step 2

System OK

2

Can you identify the type of fluid and the approximate location of the leak?

Go to Step 7

Go to Step 3

3

  1. Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas.
  2. Check for leaks at the following locations:
  3. • Sealing surfaces
    • Fittings
    • Cracked or damaged components

Can you identify the type of fluid and the approximate location of the leak?

Go to Step 7

Go to Step 4

4

  1. Completely clean the entire engine and surrounding components.
  2. Apply an aerosol-type powder (baby powder, foot powder, etc.) to the suspected area.
  3. Operate the vehicle for several kilometers/miles at normal operating temperature and at varying speeds.
  4. Identify the type of fluid, and the approximate location of the leak, from the discolorations in the powder surface.

Can you identify the type of fluid and the approximate location of the leak?

Go to Step 7

Go to Step 5

5

Use J 28428-E in order to identify the type of fluid, and the approximate location of the leak. Refer to the manufacturer's instructions when using the tool.

Can you identify the type of fluid and the approximate location of the leak?

Go to Step 7

Go to Step 6

6

  1. Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas.
  2. Check for leaks at the following locations:
  3. • Sealing surfaces
    • Fittings
    • Cracked or damaged components

Can you identify the type of fluid and the approximate location of the leak?

Go to Step 7

System OK

7

  1. Inspect the engine for mechanical damage and repair or replace as necessary. Special attention should be shown to the following areas:
  2. • Plugged or malfunctioning crankcase ventilation system. Refer to Crankcase Ventilation System Inspection/Diagnosis.
    • Higher than recommended fluid levels
    • Higher than recommended fluid pressures
    • Plugged or malfunctioning fluid filters or pressure bypass valves
    • Improperly tightened or damaged fasteners
    • Cracked or porous components
    • Improper sealants or gaskets where required
    • Improper sealant or gasket installation
    • Damaged or worn gaskets or seals
    • Damaged or worn sealing surfaces
  3. Inspect the engine for customer modifications.

Is there mechanical damage, or customer modifications to the engine?

Go to Step 8

System OK

8

Repair or replace all damaged or modified components.

Does the engine still leak oil?

Go to Step 1

System OK