Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Inspection

INSPECTION

CAUTION / NOTICE / HINT

HINT:

  • Use the same procedure for bank 1 and bank 2.
  • The following procedure is for bank 2.

PROCEDURE

1. INSPECT CYLINDER HEAD LH

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

*a

Bottom Side

*b

Intake Manifold Side

*c

Exhaust Manifold Side

-

-

Standard Warpage:

Item

Specified Condition

Bottom Side

0.05 mm (0.00197 in.)

Intake Manifold Side

0.08 mm (0.00315 in.)

Exhaust Manifold Side

0.08 mm (0.00315 in.)

Maximum Warpage:

Item

Specified Condition

Bottom Side

0.10 mm (0.00394 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 LH.

2. INSPECT CYLINDER HEAD LH FOR CRACKS

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

HINT:

If cracks are found, replace the cylinder head LH.

3. INSPECT INTAKE VALVE

(a) 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.

(b) 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

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

Standard Overall Length:

105.85 mm (4.17 in.)

Minimum Overall Length:

105.35 mm (4.15 in.)

HINT:

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

*a

Overall Length

4. INSPECT EXHAUST VALVE

(a) Using a micrometer, measure the diameter of the 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.

(b) 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 exhaust valve.

*a

Margin Thickness

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

Standard Overall Length:

110.40 mm (4.35 in.)

Minimum Overall Length:

109.90 mm (4.33 in.)

HINT:

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

*a

Overall Length

5. INSPECT INTAKE VALVE SEAT

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

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

NOTICE:

Do not rotate the intake valve while pressing it.

(c) Check the valve face and intake valve seat by using the following procedure:

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

HINT:

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

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

HINT:

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

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

Standard Width:

1.1 to 1.5 mm (0.0433 to 0.0591 in.)

*a

Width

6. INSPECT EXHAUST VALVE SEAT

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

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

NOTICE:

Do not rotate the exhaust valve while pressing it.

(c) Check the valve face and exhaust valve seat by using the following procedure:

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

HINT:

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

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

HINT:

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

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

Standard Width:

1.1 to 1.5 mm (0.0433 to 0.0591 in.)

*a

Width

7. INSPECT INNER COMPRESSION SPRING

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

Standard Free Length:

54.53 mm (2.15 in.)

Minimum Free Length:

52.43 mm (2.06 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 (Reference):

1.4 mm (0.0551 in.)

HINT:

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

*a

Deviation

*b

40 mm (1.57 in.)

8. 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

0.12 mm (0.00472 in.)

Exhaust

0.12 mm (0.00472 in.)

HINT:

If the oil clearance is more than the maximum, replace the valve and valve guide bush.

    Disassembly

    Precaution

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