Engine Cooling System - 2.0L: Removal & Installation Kia Optima III

Removal And Installation

Note. Disassembly of the thermostat would have an adverse effect, causing a lowering of cooling efficiency. Do not remove the thermostat, even if the engine tends to overheat.

Scheme 1

Scheme 2

1. Drain engine coolant so its level is below thermostat.
2. Disconnect the radiator lower hose (A).
3. Remove water inlet fitting (C), gasket (B) and thermostat (A). Tightening torque: 7.8 ~ 11.8 N.m (0.8 ~ 1.2kgf.m, 5.8 ~ 8.7 lb-ft)
4. Installation is reverse order of removal. CAUTION: Install the thermostat with the jiggle valve upward. When assembling the thermostat, place the thermostat on the housing with a protrusion of thermostat matching with a groove of the housing and install the gasket and inlet fitting. Be careful the thermostat doesn't get out of the groove on the housing.
5. Fill the engine coolant.
6. Start the engine and check for leaks.
7. Recheck the coolant level.

Scheme 3

1. Immerse the thermostat in water and gradually heat the water.
2. Check the valve opening temperature. Valve opening temperature: 82 ± 1.5°C (179.6 ± 2.7°F) Full opening temperature: 95°C (203°F) If the valve opening temperature is not as specified, replace the thermostat.
3. Check the valve lift. Valve lift : 8 mm (0.3 in.) or more at 95°C (203°F) If the valve lift is not as specified, replace the thermostat.