Exhaust Gas Recirculation: Service and Repair

Fig. 39 EGR control valve. Exc.4-153, 4-156 & V6-181 engines:

The complete EGR system should be inspected and tested. To assure proper operation of this system all passages and moving parts must operate properly free of deposits. Hoses and connections must be free from leaks.
The EGR valve should be inspected for deposits with particular attention to the poppet and seat area, Fig. 39. If deposits exceed a thin film condition, the EGR valve should be cleaned. If wear of the stem or other moving components is noted, the valve should be replaced. Extreme care should be exercised during the cleaning operation to prevent spilling of solvent on the valve diaphragm, as this will cause diaphragm failure. Do not push on diaphragm to operate valve, use vacuum source only.