Last Modified: 06-05-2026 6.11:8.1.0 Doc ID: RM100000001G45Z
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 11/2022]
Title: 2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: INSPECTION; 2020 - 2023 MY Corolla [01/2019 - 11/2022]

INSPECTION

PROCEDURE

1. INSPECT CYLINDER HEAD SUB-ASSEMBLY FOR WARPAGE

(a) Using a precision straightedge and feeler gauge, check the surfaces which contact the cylinder head sub-assembly and manifold for warpage.

Maximum Warpage

Item

Specified Condition

Bottom side

0.05 mm (0.00197 in.)

Intake manifold side

0.10 mm (0.00394 in.)

Exhaust manifold side

0.10 mm (0.00394 in.)

HINT:

If the warpage is more than the maximum, replace the cylinder head sub-assembly.

*a

Bottom Side

*b

Intake Manifold Side

*c

Exhaust Manifold Side

2. INSPECT CYLINDER HEAD SUB-ASSEMBLY FOR CRACKS

(a) Using a dye penetrant, check the intake ports, exhaust ports and bottom surface of the cylinder head sub-assembly for cracks.

HINT:

If cracks are found, replace the cylinder head sub-assembly.

3. INSPECT VALVE SEATS

(a) Apply a light coat of Prussian blue to the valve face.

*a

Width

(b) Lightly press the valve face against the valve seat.

NOTICE:

Do not rotate the valve while pressing it.

(c) Check the valve face and valve seat.

(1) If Prussian blue appears 360° around the entire valve face, the valve face is concentric.

HINT:

If the valve face is not concentric, replace the valve.

(2) If Prussian blue appears 360° around the entire valve seat, the valve seat and valve face are concentric.

HINT:

If the valve face is not concentric, resurface the valve seat.

Click here 2020 - 2023 MY Corolla [01/2019 - 11/2022]; 2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: REPAIR+

(3) Measure the width of the contact area of the valve seat and valve face.

Standard Width

Item

Specified Condition

Intake

1.0 to 1.4 mm (0.0394 to 0.0551 in.)

Exhaust

1.0 to 1.4 mm (0.0394 to 0.0551 in.)

4. INSPECT INNER COMPRESSION SPRING

(a) Using a vernier caliper, measure the free length of the inner compression spring.

Standard Free Length (New parts):

51.88 mm (2.042 in.)

HINT:

If the free length is not as specified, replace the inner compression spring.

(b) Using a steel square, measure the deviation of the inner compression spring.

Maximum Deviation:

1.3 mm (0.0512 in.)

HINT:

If the deviation is greater than the maximum, replace the inner compression spring.

*a

Deviation

*b

37.5 mm (1.48 in.)

5. INSPECT INTAKE VALVE

(a) Using a vernier caliper, measure the overall length of the intake valve.

Standard Overall Length:

109.34 mm (4.30 in.)

Minimum Overall Length:

108.84 mm (4.29 in.)

HINT:

If the overall length is less than the minimum, replace the intake valve.

*a

Overall length

(b) Using a micrometer, measure the diameter of the valve stem.

Standard Valve Stem Diameter:

5.470 to 5.485 mm (0.215 to 0.216 in.)

HINT:

If the valve stem diameter is not as specified, check the intake valve guide bush oil clearance.

Click here 2020 - 2023 MY Corolla [01/2019 - 11/2022]; 2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: INSPECTION+

(c) Using a vernier caliper, measure the valve head margin thickness.

Standard Margin Thickness:

1.0 mm (0.0394 in.)

Minimum Margin Thickness:

0.5 mm (0.0197 in.)

HINT:

If the margin thickness is less than the minimum, replace the intake valve.

*a

Margin thickness

6. INSPECT EXHAUST VALVE

(a) Using a vernier caliper, measure the overall length of the exhaust valve.

Standard Overall Length:

108.25 mm (4.26 in.)

Minimum Overall Length:

107.75 mm (4.24 in.)

HINT:

If the overall length is less than the minimum, replace the exhaust valve.

*a

Overall length

(b) Using a micrometer, measure the diameter of the exhaust valve stem.

Standard Valve Stem Diameter:

5.465 to 5.480 mm (0.215 to 0.216 in.)

HINT:

If the valve stem diameter is not as specified, check the exhaust valve guide bush oil clearance.

Click here 2020 - 2023 MY Corolla [01/2019 - 11/2022]; 2ZR-FAE (ENGINE MECHANICAL): CYLINDER HEAD: INSPECTION+

(c) Using a vernier caliper, measure the exhaust valve head margin thickness.

Standard Margin Thickness:

1.0 mm (0.0394 in.)

Minimum Margin Thickness:

0.5 mm (0.0197 in.)

HINT:

If the margin thickness is less than the minimum, replace the exhaust valve.

*a

Margin thickness

7. INSPECT VALVE GUIDE BUSH OIL CLEARANCE

(a) Using a caliper gauge, measure the inside diameter of the valve guide bush.

Standard Valve Guide Bush Inside Diameter:

5.510 to 5.530 mm (0.217 to 0.218 in.)

(b) Subtract the valve stem diameter measurement from the valve guide bush inside diameter measurement.

Standard Oil Clearance

Item

Specified Condition

Intake

0.025 to 0.060 mm (0.000984 to 0.00236 in.)

Exhaust

0.030 to 0.065 mm (0.00118 to 0.00256 in.)

Maximum Oil Clearance

Item

Specified Condition

Intake

0.080 mm (0.00315 in.)

Exhaust

0.085 mm (0.00335 in.)

HINT:

  • Oil clearance = Inside diameter - Valve stem diameter
  • If the oil clearance is more than the maximum, replace the valve and valve guide bush.