C Yukon 2WD V8-5.7L VIN R (1999)
4. Remove the IAC valve assembly.
5. Remove the O-ring.
CLEANING AND INSPECTION PROCEDURE
1. Clean the IAC valve O-ring sealing surface, the pintle valve seat, and the air passage.
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Use carburetor cleaner and a parts cleaning brush in order to remove carbon deposits. Follow instructions on the container.
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Do not use a cleaner that contains methyl ethyl ketone, an extremely strong solvent and not necessary for this type of deposit.
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Shiny spots on the pintle or seat are normal. They do not indicate misalignment or a bent pintle shaft.
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If air passage has heavy deposits, remove the throttle body for a complete cleaning.
2. Inspect the IAC valve O-ring for cuts, cracks, or distortion. Replace if damaged.
INSTALLATION PROCEDURE
IMPORTANT: If installing a new IAC valve, replace with an identical part. The IAC valve pintle shape and diameter are designed for the specific
application.
1. Measure the distance A between tip of IAC valve pintle and mounting flange.
If greater than 28 mm, use finger pressure in order to slowly retract the pintle. The force required to retract the pintle of a new valve will not cause
damage to the valve.
2. Lubricate the IAC valve O-ring with clean engine oil.
3. Install the IAC valve assembly.
NOTE: Refer to Fastener Notice in Cautions and Notices.
