Kia Optima: RCV Control Solenoid Valve. Description and OperationWhen the throttle is closed, while the engine is running at cruise rpm (tip-out), the turbocharger boost pressure raises rapidly. The pressure wave strikes a compressor blades causing a knocking noise. To prevent this the ECM opens the recirculation valve which allows excessive boost pressure to vent back to the air cleaner side of the turbocharger compressor.

Adjustment
RCV Control Solenoid Valve. SpecificationsInspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Turn the ignition switch ON.
3.
Measure the output voltage of the APS 1 and 2 at
C.T ...
Keep belts clean and dry
Seat belts should be kept clean and dry. If belts become dirty, they can be cleaned
by using a mild soap solution and warm water. Bleach, dye, strong detergents or
abrasives should not be used bec ...
Inspection
1.
Immerse the thermostat in water
and gradually heat the water.
2.
Check the valve opening temperature.
Valve opening temperature:
82 ± 1.5°C ( ...