Exhaust Gas Recirculation: Service and Repair

CAUTION:
a. Do not wash the EGR valve in solvents or degreaser. Sand blasting the valve is not recommended either, as permanent damage may result.
b. Wear approved eye protection for this cleaning procedure, to avoid possible injury to the eyes.

1. Disconnect vacuum hose from EGR valve, remove the valve retaining bolts, and the control valve.
2. With a wire wheel or brush, remove the deposits from the mounting surface and around the valve.
3. Open the control valve, with an external vacuum source, and check for excessive buildup of carbon deposits. Anything more than a thin film is excessive.
4. Using a suitable sharp edged tool, scrape the carbon deposits from the control valve poppet. Do not scratch the valve seat or dislodge the poppet from its stem.
5. Check for wear of the poppet valve and stem.
If any is noticed the control valve should be replaced.
6. Install new gasket, install the control valve.
7. Reconnect the vacuum hose to the control valve.




INTAKE MANIFOLD CLEANING


NOTE: When cleaning intake manifold EGR passages, care should be taken to ensure that all loose particles are completely removed to prevent them from clogging the EGR valve or from being ingested into the engine.


1. Disconnect vacuum hose from EGR valve, remove EGR valve retaining bolts, and the control valve.
2. Scrape carbon deposits from the EGR port using a suitable sharp edged tool. Use a wire wheel or brush to remove deposits from the valves mounting surfaces.
3. Blow deposits from EGR ports and control passages using compressed air.
4. Install EGR control valve, using new gasket.
5. Reconnect EGR vacuum hose.