Removal (LS400): Diagnosis Lexus LS II

Inspection

1. Using caliper, measure cylinder head bolt diameter .98" (25.0 mm) down from bottom end of bolt, on bolt threads. Replace cylinder head bolt if diameter is less than .378" (9.60 mm).
2. Inspect cylinder head for warpage at cylinder block and manifold areas. Replace cylinder head if warpage exceeds specification. See «CYLINDER HEAD»(ref-49513-S19383932252001011500000) under ENGINE SPECIFICATIONS.
3. Check intake manifold, air intake chamber and exhaust manifold for warpage. Replace component if warpage exceeds specification. See «WARPAGE SPECIFICATIONS»(ref-49513-S39985816582001011500000) . WARPAGE SPECIFICATIONS Application Warpage In. (mm) Air Intake Chamber .0059 (.150) Exhaust Manifold .0197 (.500) Intake Manifold .0059 (.150)
4. Inspect cylinder block deck surface for warpage. Replace cylinder block if deck warpage exceeds specification. See «CYLINDER BLOCK»(ref-49513-S25984710192001011500000) under ENGINE SPECIFICATIONS. Inspect camshaft and components. See «CAMSHAFT»(ref-49513-S06776582292001011500000) .
5. Inspect valve lifter for damage. Measure valve lifter diameter and bore diameter. Ensure oil clearance is within specification. Replace components if not within specification. See «VALVE LIFTERS»(ref-49513-S02451425252001011500000) under ENGINE SPECIFICATIONS.

Scheme 10

Scheme 11

1. Install NEW gasket for exhaust manifold on cylinder head. Install exhaust manifold gasket on cylinder head so White paint mark at center or edge of gasket faces exhaust manifold. NOTE: Install exhaust manifold gasket so White paint mark at center or edge of gasket faces exhaust manifold.
2. Install exhaust manifold. Install and tighten NEW exhaust manifold nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
3. Install cylinder head gaskets on cylinder block. Cylinder head gaskets contain a paint mark to indicate gasket application. Ensure Yellow painted mark is installed on left cylinder bank and White painted mark is installed on right cylinder bank. Paint mark is installed toward drive plate end of engine. (Scheme 10)
4. Install cylinder head. Apply light coat of oil to threads and underside of cylinder head bolts. Install washers on cylinder head bolts. Install and tighten cylinder head bolts to specification in sequence using several steps. see scheme 13 See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
5. Install camshafts. See CAMSHAFT. Check and adjust valve clearance. See «VALVE CLEARANCE ADJUSTMENT»(ref-49513-S12958173942001011500000) under ADJUSTMENTS. NOTE: There are 2 half-circular plugs for each cylinder head. Ensure both half-circular plugs are installed in each cylinder head.
6. Apply sealant at valve cover sealing areas on front of cylinder head. see scheme 5 Install valve cover using NEW gasket. Install seal washer and bolts. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
7. Install front and rear coolant by-pass housings with NEW gaskets. Tighten nuts alternately to specification. Connect engine coolant temperature sensor and temperature gauge sending unit. CAUTION: Intake manifold gaskets must be installed on cylinder heads with White paint mark facing upward.
8. Install NEW intake manifold gaskets on cylinder heads with White paint mark facing upward. (Scheme 11) Ensure holes in gasket align with holes in cylinder head. Install intake manifold with arrow on intake manifold pointing forward, toward timing belt end of engine.
9. Install EGR pipe on exhaust manifold using NEW gasket and nuts. Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Install dipstick tubes using NEW "O" rings.
10. Install timing belt rear plates. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). Install camshaft sprockets and timing belt. See TIMING BELT. Install engine wiring. Install and tighten nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
11. Install and tighten intake manifold bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000). If installing injector on delivery pipe, install NEW grommet on injector. Coat NEW "O" ring with gasoline. Install NEW "O" ring on injector. Using twisting motion, install injector in delivery pipe.
12. Install NEW insulators and spacers for delivery pipe on intake manifold. Install injectors and delivery pipe. Ensure electrical connector on injector is facing outward, toward outside of delivery pipe.
13. Ensure injectors rotate smoothly with delivery pipe installed. If injectors do not rotate smoothly, check for damaged "O" ring. Install and tighten delivery pipe nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
14. To install remaining components, reverse removal procedure using NEW gaskets. Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-49513-S34527251092001011500000).
15. Apply sealant in groove on rear of coolant inlet housing before installing. Apply soapy water solution to NEW coolant inlet housing "O" ring before installing. Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-49513-S07553328822001011500000). Adjust control cables and ignition timing.