For 1990-2009 cars

1. Clean the sealing surfaces.
2. Inspect the cylinder head for the following.

• | Cracks, damage or pitting in the combustion chambers

• | Debris in the oil galleries--Continue to clean the galleries until all debris is removed

• | Coolant leaks or damage to the deck face sealing surface--Damage to any gasket surfaces

• | Damage to any threaded bolt holes

• | Burnt or eroded areas in the combustion chamber

• | Cracks in the exhaust ports and combustion chambers

• | External cracks in the water passages

• | Restrictions in the intake or exhaust passages

• | Restrictions in the cooling system passages

• | Rusted, damaged or leaking core plugs

3. If the cylinder head is cracked or damaged, it must be replaced. No welding or patching of the cylinder head is recommended.
4. Measure the clearance between the straight-edge and the cylinder head deck face using a feeler gage at four points along the straight-edge.
5. Check the sealing surfaces for deformation and warpage. The cylinder head sealing surfaces must be flat within 0.025 mm (0.001 in) maximum.
6. Measure the height of the cylinder head from sealing surface to sealing surface. The cylinder head height should be 133.975-134.025 mm (5.274-5.276 in). If the cylinder head height is less than 133.9 mm (5.271 in), replace the cylinder head.

### Valve Inspection

1. Inspect the valve for damage from the head to tip for the following conditions.

• | pitting in the valve seat area (1)

• | lack of valve margin (2)

• | bending in the valve stem (3)

• | pitting or excessive wear in the stem (4)

• | worn valve key grooves (5)

• | worn valve tip (6)

2. Replace the valve if any of these conditions exist.
3. Inspect the valve springs. If the valve spring ends are not parallel, replace the valve spring.
4. Inspect the valve spring seating surface of the valve rotators for wear or gouges. Replace as required.

### Cleaning Procedure

1. Clean the cylinder head.
2. Clean the valve guides.
3. Clean all of the threaded holes.
4. Clean the valves of carbon, oil, and varnish.