Kia Optima Hybrid Owner's Manual Quiz
Engine Mechanical System

Engine and Transaxle Assembly Repair Procedures

In this manual: Engine Mechanical System
General Information — 4Engine Mechanical System — 50Engine Electrical System — 20Emission Control System — 30Engine Control System/Fuel System — 84Automatic Transmission — 98Drive Shaft and Axle — 15Suspension System — 36Steering — 12Restraints — 50Brake System — 38Body (Interior and Exterior) — 54Body Electrical System — 233Heating, Ventilation, and Air Conditioning — 57
32steps
~192min
4/5difficulty
010203040509.87N·mlb·ft
Tightening torque found on this page
Done 0 of 32

Removal
  • Use fender covers to avoid damaging painted surfaces.
  • To avoid damage, carefully disconnect the wiring connectors by holding the connector body.
  • To release fuel pressure before removing the engine assembly, start the engine with the fuel pump relay removed. Then turn the ignition off after the engine stops.
  • Label all wires and hoses to avoid incorrect connection.
  • Be sure to read and follow the "General Information on Safety and Caution" before performing any work on the high voltage system. Failure to follow safety instructions may result in serious electrical shock.
  • Always disconnect the high-voltage circuit in accordance with the "High Voltage Disconnection Procedure" before performing any work on the high-voltage system to avoid serious electric shock.
  1. Disconnect the high voltage circuit (refer to "High Voltage Disconnection Procedure" in this group).
  2. Remove the engine cover (A).
  3. Remove the air duct (A).

    Tightening torque: 7.8 ~ 9.8 N·m

  4. Remove the air cleaner assembly.
    1. Disconnect the breather hose (A).
    2. Disconnect the air intake hose (B) and remove the air cleaner assembly (C). Tightening torque: Hose clamp bolt: 2.9 ~ 4.9 N·m Air cleaner mounting bolts: 7.8 ~ 9.8 N·m
      • When installing the air intake hose, align the clamp plate with the hose stopper.
      • When installing the air intake hose, align the center of the mark on the hose with the rib of the throttle body.
  5. Remove the lower covers (A, B).

    Tightening torque: 7.8 ~ 11.8 N·m
    When removing the lower cover (B), remove the mounting bolts of the bracket, then remove the lower cover and the mounting bracket assembly.
  6. Loosen the drain plug and drain the engine coolant. Remove the radiator cap to drain the coolant faster. (Refer to Cooling System in this group.)
  7. Loosen the drain plug and drain the inverter coolant. Remove the reservoir cap to drain the coolant faster. (Refer to HT Group - "Coolant".)
  8. Disconnect the upper radiator hose (A) and lower hose (B).
  9. Remove the Hybrid Power Control Unit (HPCU). (Refer to HC Group - "HPCU".)
  10. Remove the inverter pan (A).

    Tightening torque: 8.8 - 13.7 N·m

  11. Recover the refrigerant, then remove the high pressure line (A) and low pressure line (B). (Refer to HA Group - "Electric Compressor".)
  12. Disconnect the ECM connectors (A) from the ECM, the fuse block connector (B) from the fuse/relay block, and the engine ground wire (C). Then remove the wiring protector (D).
  13. Disconnect the cooling system hoses from the Hybrid Starter Generator (HSG) (A) and the Electric Water Pump (EWP) (B).
  14. Disconnect the transaxle harness connectors and the control cable from the transaxle. (Refer to AT Group.)
  15. Disconnect the heater hoses (A).
  16. Disconnect the fuel hose (A) and the hose (B) of the purge control solenoid valve (PCSV).
  17. Remove the front muffler (A).
  18. Remove the steering universal joint mounting bolt (A). (Refer to ST Group.)
  19. Remove the front wheels. (Refer to SS Group - "Wheel".)
  20. Remove the lower arms (A). (Refer to SS Group - "Front Lower Arm".)
  21. Remove the stabilizer bar links (A). (Refer to SS Group - "Front Stabilizer Bar".)
  22. Remove the tie rod ends (A). (Refer to ST Group - "Steering Gear Box".)
  23. Disconnect the drive shafts (A) from the axle hubs. (Refer to DS Group - "Front Axle Hub / Knuckle".)
  24. Remove the roller rod bracket (A). Tightening torque: Bolt (B): 107.9 ~ 128 N·m Bolt (C): 49.0 ~ 64 N·m
  25. Remove the roller rod bracket (A).

    Tightening torque: 49.0 ~ 69 N·m

  26. Support the subframe (A) with a jack, then remove the subframe mounting bolts and nuts. (Refer to SS Group - "Front Crossmember".) Tightening torque: Subframe mounting bolts and nuts: 156.9 ~ 176 N·m (16.0 ~ 18.0 kgf·m, 115.7 ~ 130.2 ft-lbf) Stopper bolts: 44.1 ~ 59 N·m
    • After removing the subframe mounting bolts and nuts, the engine and transaxle assembly may drop. Support it securely with a floor jack.
    • Before removing the engine and transaxle assembly, make sure all hoses and connectors are disconnected.
  27. Support the engine and transaxle assembly with a floor jack.
  28. Disconnect the engine ground cable (A).

    Tightening torque: 10.8 ~ 13.7 N·m

  29. Remove the engine mount bracket (B).

    Tightening torque: 88.3 ~ 108 N·m

  30. Disconnect the transaxle ground cable (A).
  31. Remove the automatic transaxle support bracket bolt (B) after removing the cover (A).

    Tightening Torque: 107.9 ~ 128 N·m

  32. Lower the jack together with the engine and transaxle assembly, then remove the engine and transaxle assembly by raising the vehicle.
    When removing the engine and transaxle, be careful not to damage surrounding parts or body components.

Installation

Installation is in the reverse order of removal. Add all required fluids and check for leaks. Connect the GDS. Check for DTCs, note them, and clear them. Recheck.
  • Adjust the shift cable.
  • Fill the engine with engine oil.
  • Fill the transmission with fluid.
  • Fill the radiator and the coolant reservoir with engine coolant.
  • Fill the inverter radiator and the coolant reservoir with coolant.
  • Clean the battery terminal posts and cable clamps, then assemble.
  • Inspect for fuel leaks.
  • After assembling the fuel line, turn the ignition switch ON (do not operate the starter) so that the fuel pump operates for about two seconds and pressurizes the fuel line.
  • Repeat this procedure two or three times, then check all fuel line connections for leaks.
  • Bleed air from the hybrid engine cooling system. (Refer to Group BT - "Engine Coolant")
  • Bleed air from the engine cooling system.
  • Start the engine and let it run until warm (until the radiator fan cycles 3 or 4 times).
  • Turn the engine off. Check the coolant level in the radiator and add coolant if necessary. This allows trapped air to be removed from the cooling system.
  • Tightly close the radiator cap, then restart the engine and check for leaks.
The HCU must learn the engine clutch engagement point to reduce shock when engine power is connected to the transaxle. Perform the clutch pressure sensor calibration after installing the CPS, HCU, engine, or hybrid drive motor (refer to "Hybrid Control System" in Group HC).

Test yourself

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