Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Cylinder Head & Manifolds: Inspection
1999 Lexus SC 400SECTION Inspection
WARNING: This page is about a different car, the 1998 Lexus SC 300, 1998 Lexus GS 300, 1997 Lexus SC 300, and 1997 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
- Using caliper, measure cylinder head bolt diameter 2.0" (50 mm) down from bottom of bolt head. Replace cylinder head bolts if diameter is less than.421" (10.70 mm).
- Using a straightedge and feeler gauges, check for warpage at cylinder head surface, and intake and exhaust manifold sealing areas. Replace cylinder head if warpage exceeds specification. See CYLINDER HEAD under ENGINE SPECIFICATIONS.
- Check warpage of intake manifold, air intake chamber and exhaust manifold. Replace component if warpage exceeds specification. See WARPAGE SPECIFICATIONS .WARPAGE SPECIFICATIONS
Application In. (mm) Air Intake Chamber .0059 (.150) Exhaust Manifold .0200 (.500) Intake Manifold .0059 (.150) - Inspect cylinder block deck surface for warpage. Replace cylinder block if deck warpage exceeds specification. See CYLINDER BLOCK under ENGINE SPECIFICATIONS. Inspect camshaft and components. See CAMSHAFT .
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.