Leak Testing
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WARNING:
The normal operating temperature of the exhaust system is very high. Therefore, never work around or attempt to service any part of the exhaust system until it is cooled. Special care should be taken when working near the catalytic converter. The temperature of the converter rises to a high level after a short period of engine operation time.
- Raise and support vehicle. Refer to HOISTING, STANDARD PROCEDURE
.CAUTION:
The air pressure must not exceed 4 psi, otherwise engine damage can occur.
- Connect the (special tool #8404-ECT, Exhaust Cone, Truck), to an adjustable air pressure regulator.
- Attach shop air to the air pressure regulator.
- Adjust the air pressure regulator to 4 psi.
- Insert the (special tool #8404-ECT, Exhaust Cone, Truck), into the tail pipe.
- If the vehicle is equipped with dual exhaust, use the (special tool #8404-ECT, Exhaust Cone, Truck), equipped attached plug. Plug one side of the dual exhaust pipe. Pressurize the other as described.
- Apply a mixture of liquid dish soap and water to the following areas:
- All welded joints from 6 inches rearward of the downstream O2 sensor forward
- O2 sensor seal points
- O2 sensor boss welds
- Flange/joint connection(s)
- Exhaust manifold to cylinder head connection(s)
- EGR solenoid gasket base and tube seal points (if equipped).
- Watch for the liquid/soapy water to bubble.
- Use the following definitions to help determine if system or component repair/replacement is necessary:
- Type 1 Leak is defined as a leak where very small foam like bubbles 1 mm (.039 in.) or less appear. Any Type 1 or greater leaks found in welded joints, O2 sensor seal points or O2 sensor boss welds must be repaired or the component must be replaced.
- Type 2 Leak is defined as a leak where larger bubbles 8 mm (.031 in.) or greater appear. Any Type 2 or greater leaks found in flange or joint connections, exhaust manifold to cylinder head connections, or EGR gasket and tube seal points must be repaired or the components must be replaced.
| Leak Location | Repair required if results at 4 psi reveal bubble size: |
|---|---|
| Welded joints | Type 1 - 1 mm (0.039 in.) or greater |
| O2 Sensor seal points | Type 1 - 1 mm (0.039 in.) or greater |
| O2 Sensor boss welds | Type 1 - 1 mm (0.039 in.) or greater |
| Flange/joint connections | Type 2 - 8 mm (0.315 in.) or greater |
| Exhaust Manifold to cylinder head connections | Type 2 - 8 mm (0.315 in.) or greater |
| EGR gasket and tube seal points | Type 2 - 8 mm (0.315 in.) or greater |
If a leak is found that matches the above definition, repair or replace the component as necessary.
Once the repair is complete, repeat the procedure to verify that all leaks have been repaired.