LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 1998 >> SC 400 >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments >> Valve Clearance >> LS400
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Valve Clearance: LS400

NOTE: Check and adjust valves with engine cold.
  1. Drain engine coolant. Remove battery cover. Remove air cleaner inlet. Remove engine cover. Remove air cleaner and intake air connector assembly. Disconnect PS air hose from timing belt cover clamp. Disconnect wire clamp. Disconnect radiator reservoir outlet hose from water inlet housing. Remove bolt, nut and disconnect outlet pipe from timing belt cover and left cylinder head. Remove bolts and No. 3 timing belt cover (upper cover with gasket).
  2. Remove ignition coils. Remove bolts, seal washers and right valve cover. Remove transmission oil dipstick. Disconnect PCV hose. Disconnect engine wire clamp from delivery pipe wire bracket. Remove bolts, seal washers and left valve cover.
  3. Rotate crankshaft clockwise until piston No. 1 is at TDC of compression stroke. Ensure groove on crankshaft pulley aligns with "0" timing mark on timing belt cover. Timing marks on camshaft pulleys should align with timing marks on timing belt cover No. 4 (upper inner cover). See Fig 1. If timing marks do not align rotate crankshaft clockwise 360 degrees.
  4. Measure and record clearance of intake valves for cylinders No. 1, 2, 5, 7 and 8, and exhaust valves for cylinders No. 1, 4 and 8. See Figure. Rotate crankshaft 360 degrees. Measure and record clearance of intake valves for cylinders No. 3, 4 and 6, and exhaust valves for cylinders No. 2, 3, 5, 6 and 7.
  5. Compare measured clearance with specified clearance. See VALVE CLEARANCE SPECIFICATIONS TABLE (LS400 & SC400) . If clearance is within specification, go to step 8). If clearance is not within specification, rotate crankshaft until camshaft lobe of valve to be adjusted is facing upward, away from shim.
    VALVE CLEARANCE SPECIFICATIONS

    Application In. (mm)
    Intake .006-.010 (.15-.25)
    Exhaust .010-.014 (.25-.36)
  6. Remove timing belt from camshaft timing pulleys. See appropriate article in the ENGINES section. Remove camshafts for appropriate bank and valve. See appropriate article in the ENGINES section.
  7. Remove valve lifter and adjusting shim. Ensure not to drop adjusting shim into lifter line when removing valve lifter. Select a shim of appropriate thickness. See SELECTING SHIMS  under VALVE CLEARANCE. Recheck valve clearance after shim is installed.
  8. To complete installation, reverse removal procedure. Remove old valve cover seal packing material. Install NEW Seal Packing (08826-00080) material. See Fig 2. Use NEW gaskets as necessary. Refill engine coolant, if necessary. Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS .
Fig 1: Identifying Timing Marks On Camshaft Pulleys & On Timing Belt Cover No. 4 (Upper Inner Cover - LS400 & SC400)
G98J10438Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Cylinder Head Cover Seal Material Locations (LS400)
G98A10439Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002