Cylinder Head Repair Procedures

Removal

Use fender covers to avoid damaging painted surfaces. To prevent damage to the cylinder head, wait until the engine coolant temperature drops below normal operating temperature before removing it. When handling the metal gasket, be careful not to bend the gasket or damage the gasket contact surface. To avoid damage, carefully disconnect the wiring connectors by holding the connector body.

Label all wires and hoses to avoid incorrect connection.

Be sure to read and follow the "General Safety Information and Caution" before performing any work on the high voltage system. Failure to follow the safety instructions may result in serious injury from electric 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. 1
   Disconnect the high voltage circuit (refer to "High Voltage Disconnection Procedure" in this group).
2. 2
   Remove the engine cover.
3. 3
   Remove the air duct and air cleaner assembly. (Refer to Engine and Transaxle Assembly in this group)
4. 4
   Remove the under covers. (Refer to Engine and Transaxle Assembly in this group)
5. 5
   Remove the right front wheel. (Refer to Group SS - "Wheel")
6. 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. 7
   Disconnect the upper radiator hose and lower hose. (Refer to Cooling System in this group)
8. 8
   Disconnect the wiring connectors and wire harness clips, and remove the wiring and protector from the cylinder head and intake manifold.

   1. Oil Control Valve (OCV) intake connector (A).

      

   2. Oil Control Valve (OCV) exhaust connector (A).

      

   3. Oil Pressure Sensor (OPS) connector (A), A/C compressor switch connector (B), and Hybrid Starter Generator (HSG) sensor connector (C).

      

   4. Injector connectors (A).

      

   5. Ignition coil connectors (A).

      

   6. Electronic Throttle Control (ETC) connector (A), Manifold Absolute Pressure Sensor (MAPS) and Intake Air Temperature Sensor (IATS) connector (B), Knock Sensor connector (C), and Intake Camshaft Position Sensor (CMPS) connector (D).

      

   7. Disconnect the engine coolant temperature sensor (ECTS) connector (A), condenser connector (B), crankshaft position sensor (CKPS) connector (C), oxygen sensor connectors (D), exhaust camshaft position sensor (CMPS) connector (E), and purge control solenoid valve (PCSV) connector (F).

      

9. 9
   Disconnect the heater hoses. (Refer to Engine and Transaxle Assembly in this group)
10. 10
    Disconnect the fuel hose (A) and the hose (B) of the purge control solenoid valve (PCSV).

    

11. 11
    Disconnect the water hoses (A).

    

12. 12
    Remove the water temperature control assembly (A).

    

13. 13
    Remove the timing chain. (Refer to Timing System in this group)
14. 14
    Remove the intake and exhaust manifolds. (Refer to Intake and Exhaust System in this group)
15. 15
    Remove the intake CVVT assembly (A) and the exhaust CVVT assembly (B).

    

    When removing the CVVT assembly bolt, do not allow the camshaft to rotate with a wrench at position A.

    

16. 16
    Remove the camshaft.

    1. Remove the camshaft front bearing cap (A) with the upper bearing (B).

       

    2. Remove the camshaft bearing caps (A) in the sequence shown.

       

    3. Remove the camshafts (A).

       

    4. Remove the exhaust camshaft lower bearing cap (A).

       

17. 17
    Remove the intake Oil Control Valve (OCV) (A) using a Torx key.

    

18. 18
    Remove the exhaust Oil Control Valve (OCV) (A) using a Torx key.

    

19. 19
    Remove the intake camshaft position sensor (CMPS) (A).

    

20. 20
    Remove the exhaust camshaft position sensor (CMPS) (A) after removing the engine mount and camshaft position sensor cover (B).

    

21. 21
    Remove the cylinder head.

    1. Using a triple square wrench, loosen the 10 cylinder head bolts evenly in several passes in the sequence shown, then remove them along with the plate washers.

       

       Cylinder head distortion or cracking may result if the bolts are loosened in the wrong order.

    2. Lift the cylinder head (A) off the dowels on the cylinder block and place the cylinder head on wooden blocks on the workbench.

       Be careful not to damage the contact surfaces of the cylinder head and cylinder block.

    3. Remove the cylinder head gasket (B).

       

Disassembly

Identify the MLA (mechanical lash adjuster), valves, and valve springs as they are removed so that each component can be reinstalled in its original position.

1. 1
   Remove the MLA (A).

   

2. 2
   Remove the valves.

   1. Using SST (09222-3K000, 09222-3K100), compress the valve spring and remove the valve cotter (keeper).

      

   2. Remove the spring retainer.
   3. Remove the valve spring.
   4. Remove the valve.
   5. Using thin-tip pliers, remove the valve stem seal.

      Do not reuse the old valve stem oil seals.

Inspection

1. 1
   Inspect for flatness. Using a precision straightedge and feeler gauge, measure the cylinder block and manifold mating surfaces for distortion. Cylinder head gasket surface flatness Standard: Less than 0.05 mm (0.0019 in.) overall Less than 0.02 mm (0.0007 in.) for any 100 mm (3.9370 in.) x 100 mm (3.9370 in.) section Manifold mounting surface flatness (intake/exhaust) Standard: Less than 0.10 mm (0.0039 in.)

   

2. 2
   Inspect for cracks. Check the combustion chamber, intake ports, exhaust ports and the cylinder head surface for cracks. If any cracks are found, replace the cylinder head.
3. 3
   Inspect the valve stems and valve guides.

   1. Using a caliper gauge, measure the valve guide inside diameter. Valve guide inside diameter Intake/Exhaust: 5.500 - 5.512 mm (0.21654 - 0.21701 in.)

      

   2. Using a micrometer, measure the valve stem diameter. Valve stem outside diameter Intake: 5.465 - 5.480 mm (0.21516 - 0.21575 in.) Exhaust: 5.458 - 5.470 mm (0.21498 - 0.21535 in.)

      

   3. Subtract the valve stem diameter measurement from the valve guide inside diameter measurement. Valve stem-to-guide clearance [Standard] Intake: 0.020 - 0.047 mm (0.00078 - 0.00185 in.) Exhaust: 0.030 - 0.054 mm (0.00118 - 0.00212 in.) [Limit] Intake: 0.070 mm (0.00275 in.) Exhaust: 0.090 mm (0.00354 in.) If the clearance exceeds the limit, replace the valve or cylinder head.
4. 4
   Inspect the valves.

   1. Make sure the valve face is ground to the correct valve face angle.
   2. Check the valve face for wear. If the valve face is worn, replace the valve.
   3. Check the valve head margin thickness. Valve head margin thickness [Standard] Intake: 1.02 mm (0.0401 in.) Exhaust: 1.09 mm (0.0429 in.)

      

      If the margin thickness is less than the minimum, replace the valve.
   4. Check the valve length. Valve length [Standard] Intake: 113.18 mm (4.4559 in.) Exhaust: 105.84 mm (4.1669 in.) [Limit] Intake: 112.93 mm (4.4461 in.) Exhaust: 105.59 mm (4.1571 in.)
   5. Check the valve stem tip for wear. If the valve stem tip is worn, replace the valve.
5. 5
   Inspect the valve seats.

   1. Check the valve seat for signs of overheating and improper contact with the valve face. If necessary, replace the cylinder head.
   2. Inspect the valve guide for wear. If the valve guide is worn, replace the cylinder head.
6. 6
   Inspect the valve springs.

   1. Using a steel square, measure the valve spring squareness.
   2. Using a caliper, measure the valve spring free length. Valve spring [Standard] Free height: 44.45 mm (1.7500 in.) Squareness: Less than 1.5°

      

      If the free length is not within specification, replace the valve spring.
7. 7
   Inspect the MLA. Using a micrometer, measure the outside diameter of the MLA. MLA outside diameter Intake/Exhaust: 27.964 - 27.980 mm (1.1010 - 1.1016 in.)

   MLA outside diameter: 31.964 - 31.980 mm (1.2584 - 1.2590 in.)

8. 8
   Using a caliper gauge, measure the MLA bore inside diameter in the cylinder head. Tappet bore inside diameter: 32.000 - 32.025 mm (1.2598 - 1.2608 in.)
9. 9
   Subtract the MLA outside diameter from the tappet bore inside diameter. MLA-to-tappet bore clearance [Standard]: 0.020 - 0.061 mm (0.00078 - 0.00240 in.) [Limit]: 0.070 mm (0.00275 in.)
10. 10
    Inspect the cams. Using a micrometer, measure the cam lobe height. Cam lobe height [Standard] Intake: 43.20 - 43.40 mm (1.7008 - 1.7087 in.) Exhaust: 44.40 - 44.60 mm (1.7480 - 1.7559 in.)

    

    If the cam lobe height is less than the standard value, replace the camshaft.
11. 11
    Inspect the camshaft journal surfaces for wear. If a journal is excessively worn, replace the camshaft.
12. 12
    Inspect the camshaft journal oil clearance.

    1. Clean the camshaft bearing caps and journals.
    2. Install the camshafts on the cylinder head.
    3. Place a strip of Plastigage on each camshaft journal.

       

    4. Install the bearing caps.

       Do not rotate the camshaft.

    5. Remove the bearing caps.
    6. Measure the plastigage at its widest point. Bearing oil clearance [Standard] Intake: No. 1: 0.022 - 0.057 mm (0.00087 - 0.00224 in.) No. 2, 3, 4, 5: 0.045 - 0.082 mm (0.00177 - 0.00323 in.) Exhaust: No. 1: 0 - 0.032 mm (0 - 0.00126 in.) No. 2, 3, 4, 5: 0.045 - 0.082 mm (0.00177 - 0.00323 in.) [Limit] Intake: No. 1: 0.090 mm (0.00354 in.) No. 2, 3, 4, 5: 0.120 mm (0.00472 in.) Exhaust: No. 1: 0.090 mm (0.00354 in.) No. 2, 3, 4, 5: 0.120 mm (0.00472 in.)

       

       If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the cylinder head.
    7. Completely remove the plastigage.
    8. Remove the camshafts.
13. 13
    Inspect the camshaft end play.

    1. Install the camshafts.
    2. Using a dial indicator, measure the camshaft end play by moving the camshaft back and forth. Camshaft end play [Standard]: 0.04 - 0.16 mm (0.0016 - 0.0063 in.) [Limit]: 0.20 mm (0.0078 in.)

       

       If the end play exceeds the limit, replace the camshaft. If necessary, replace the cylinder head.
    3. Remove the camshafts.
14. 14
    Check the cylinder head bore identification mark. Cylinder head bore identification mark

    

    Cylinder Head Specifications

    Grade	Mark	Exhaust No. 1 Cylinder head bore inside diameter
    a	A	40.000 - 40.008 mm (1.57480 - 1.5751 in.)
    D	B	40.008 - 40.016 mm (1.57511 - 1.57543 in.)
    c	C	40.016 - 40.021 mm (1.57543 - 1.57563 in.)

15. 15
    Select the exhaust camshaft bearing grade the same as the cylinder head grade, as shown in the table below. Exhaust camshaft bearing identification mark

    

    Exhaust Camshaft Bearing Specifications

    Cylinder Head Bore Grade	Bearing grade for installation (color)	Bearing Thickness
    A (A)	C (green)	1.996 - 2.000 mm (0.07858 - 0.07874 in.)
    B (B)	B (none)	2.000 - 2.004 mm (0.07874 - 0.07890 in.)
    C (C)	A (black)	2.004 - 2.008 mm (0.07890 - 0.07905 in.)

    
    

    Oil clearance: 0 - 0.032 mm (0 - 0.00126 in.)

16. 16
    Inspect the CVVT for smooth rotation.

    1. Clamp the camshaft in a vise. Be careful not to damage the cam lobes and journals in the vise.
    2. Make sure the CVVT is locked by turning it clockwise or counterclockwise. It should not rotate.
    3. Intake CVVT: Seal one of the two advance holes in the camshaft journal with tape. Exhaust CVVT: Seal one of the two retard holes in the camshaft journal with tape. [Intake]

       

       [Exhaust]

       

    4. Intake CVVT: Apply approx. 150 kPa (1.5 kgf/cm², 21 psi) of compressed air to the unsealed supply hole to unlock the lock. Exhaust CVVT: Apply approx. 150 kPa (1.5 kgf/cm², 21 psi) of compressed air to the unsealed retard hole to unlock the lock.

       When applying compressed air, cover the oil passages with a cloth to prevent oil from splashing.

    5. Intake CVVT: When applying compressed air, rotate the CVVT in the advance direction (counterclockwise) within its phase range, and make sure the CVVT rotates smoothly. Exhaust CVVT: When applying compressed air, rotate the CVVT in the retard direction (clockwise), and make sure the CVVT rotates smoothly. CVVT phase range: Intake: 22.5°±1° (from most retarded position to most advanced position). Exhaust: 20°±1° (from most advanced position to most retarded position).

       

    6. Intake CVVT: Rotate the CVVT to the most retarded position (clockwise), then make sure the CVVT is locked. Exhaust CVVT: Rotate the CVVT to the most advanced position (counterclockwise), then make sure the CVVT is locked.

Installation

Thoroughly clean all parts to be reassembled. Before installing parts, apply fresh engine oil to all sliding and rotating surfaces. Replace all seals with new ones.

1. 1
   Install the valves.

   1. Using SST (09222-4A000), install a new oil seal.

      Do not reuse the old valve stem oil seals. Improper seal installation may cause oil to leak past the valve guides.

      

   2. Install the valve, valve spring and spring seat.

      Position the valve springs so that the side coated with enamel faces the valve spring retainer, then install the retainer.

   3. Using SST (09222-3K000, 09222-3K100), compress the spring and install the valve cotters. After installing the valves, make sure the cotters are correctly seated before releasing the valve spring compressor.

      

      Do not depress the valve spring retainer more than 10 mm (0.4 in.).

   4. Lightly tap the end of each valve stem two or three times with a wooden hammer handle to ensure proper seating of the valve and cotter.
2. 2
   Install the MLA after applying engine oil. Make sure the MLA rotates smoothly by hand.

   

   The MLA can be reinstalled in its original position. However, the valve clearance must be checked and adjusted accordingly before installing the cylinder head on the cylinder block. Refer to General Information in EM for valve clearance inspection and adjustment.

Installation

Thoroughly clean all parts to be assembled. Always use a new cylinder head gasket and manifold gasket. The cylinder head gasket is a metal gasket. Be careful not to bend it. Always use new cylinder head bolts. Cylinder head bolts are torque-to-yield bolts designed to permanently stretch beyond the elastic limit when tightened. If the bolts are removed and reused, they may break or fail to maintain clamping force. Turn the crankshaft and set No. 1 piston to TDC.

1. 1
   Install the oil control valve (OCV) filter.

   

   Keep the oil control valve (OCV) filter clean.

2. 2
   Install the cylinder head gasket (A) on the cylinder block.

   Pay attention to the installation direction. Apply liquid sealant (Loctite 5900H or equivalent) to the edge of the cylinder head gasket on both the upper and lower sides. (At position "B") Assemble the cylinder head within five minutes after applying the sealant.

   

3. 3
   Install the cylinder head carefully so as not to damage the gasket with the lower end of the face.
4. 4
   Install the cylinder head bolts.

   1. Do not apply engine oil to the cylinder head bolts.
   2. Using SST (09221-4A000), tighten the cylinder head bolts and flat washers in several passes in the specified sequence.

   Tightening torque: 32.4 ~ 36 N·m + 90~95° + 90~95°

   

   Always use new cylinder head bolts. Cylinder head bolts are torque-to-yield bolts designed to permanently stretch beyond the elastic limit when tightened. If the bolts are removed and reused, they may break or fail to maintain clamping force.

5. 5
   Install the intake camshaft position sensor (CMPS) (A).

   Tightening torque: 9.8 ~ 11.8 N·m

   

6. 6
   Install the exhaust camshaft position sensor (CMPS) (A), engine bracket, and camshaft position sensor cover (B). Tightening torque: Bolt A: 9.8 ~ 11.8 N·m Bolt B: 27.5 ~ 31 N·m

   

7. 7
   Install the intake oil control valve (OCV) (A).

   Tightening torque: 9.8 ~ 11.8 N·m

   

8. 8
   Install the oil control valve (OCV) (A).

   Tightening torque: 9.8 ~ 11.8 N·m

   

   Do not reuse the oil control valve (OCV) if it has been dropped. Keep the oil control valve (OCV) filter clean. Do not hold the sleeve (A) of the oil control valve (OCV) during service. If the oil control valve (OCV) is installed on the engine, do not move the engine by holding the OCV connector.

   

9. 9
   Install the camshafts.

   Apply a thin coat of engine oil to the camshaft journals.

   1. Install the exhaust camshaft lower bearing (A).

      

   2. Install the camshafts (A).

      

   3. Install the exhaust camshaft upper bearing (A) onto the camshaft front bearing cap.

      

   4. Install the camshaft bearing caps (A) in their original positions. Tightening sequence: Group A > Group B > Group C. Tightening torque: Step 1 M6: 5.9 N·m M8: 14.7 N·m Step 2 M6: 10.8 - 12.7 N·m M8: 27.5 - 31 N·m

      

      Be careful not to change the position or direction of the bearing caps.

10. 10
    Install the intake CVVT assembly (A) and exhaust CVVT assembly (B).

    Tightening Torque: 53.9 ~ 64 N·m

    

    When installing the CVVT assembly bolt, do not allow the camshaft to rotate with a wrench at position A.

    

11. 11
    Install the intake manifold and exhaust manifold. (Refer to Intake and Exhaust Systems in this group)
12. 12
    Install the timing chain. (Refer to Timing System in this group)
13. 13
    Inspect and adjust the valve clearance. (Refer to General Information in this group)
14. 14
    Install the water temperature control unit (A). Tightening torque: Bolts: 14.7 ~ 19.6 N·m Nut: 18.6 ~ 24 N·m

    

15. 15
    Install the cylinder head cover.

    1. Before assembly, remove the hardened sealant located on the upper mating surface between the timing chain cover and the cylinder head cover.
    2. After applying sealant (Loctite 5900H or equivalent), assemble within 5 minutes.

       Bead width: 2.5 mm (0.10 in)

       

    3. Install the cylinder head cover (A), tightening the bolts as follows. Tightening torque: Step 1: 3.9 ~ 5.9 N·m Step 2: 7.8 ~ 9.8 N·m

       

       

       Do not reuse the cylinder head cover gasket. Do not perform the baking and/or purging test within 30 minutes after installing the cylinder head cover.

16. 16
    Connect the water hoses (A). (If equipped)

    

17. 17
    Connect the fuel hose (A) and the purge control solenoid valve (PCSV) hose (B).

    

18. 18
    Connect the heater hoses. (Refer to Engine and Transaxle Assembly in this group)
19. 19
    Connect the wiring connectors and clips, and install the wiring and cylinder head and intake manifold cover.

    1. Oil Control Valve (OCV) intake connector (A).

       

    2. Oil Control Valve (OCV) exhaust connector (A).

       

    3. Connect the oil pressure switch (OPS) connector (A), the A/C compressor switch connector (B), and the hybrid starter generator (HSG) sensor connector (C).

       

    4. Injector connectors (A).

       

    5. Ignition coil connectors (A).

       

    6. Electronic Throttle Control (ETC) connector (A), Manifold Absolute Pressure Sensor (MAPS) and Intake Air Temperature Sensor (IATS) connector (B), Knock Sensor connector (C), and Intake Camshaft Position Sensor (CMPS) connector (D).

       

    7. Disconnect the engine coolant temperature sensor (ECTS) connector (A), condenser connector (B), crankshaft position sensor (CKPS) connector (C), oxygen sensor connectors (D), exhaust camshaft position sensor (CMPS) connector (E), and purge control solenoid valve (PCSV) connector (F).

       

20. 20
    Connect the upper radiator hose and lower hose. (Refer to Cooling System in this group)
21. 21
    Install the right front wheel. (Refer to Group SS - "Wheel")
22. 22
    Install the lower covers. (Refer to Engine and Transaxle Assembly in this group)
23. 23
    Install the air duct and air cleaner assembly. (Refer to Engine and Transaxle Assembly in this group)
24. 24
    Install the engine cover.
25. 25
    Connect the negative battery cable to the right side trim panel of the luggage compartment. (Refer to Engine and Transaxle Assembly in this group)
26. 26
    Install the safety plug into the luggage compartment. (Refer to Engine and Transaxle Assembly in this group)
27. 27
    Add all required fluids and check for leaks. Connect the GDS. Check for DTCs, note them, and clear them. Recheck.

    Fill the engine with engine oil. Fill the radiator and the coolant reservoir with engine 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 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.