4.3L V8: Diagnosis Lexus LS III

TROUBLE SHOOTING

To trouble shoot engine mechanical components, see ENGINE MECHANICAL in BASIC TROUBLE SHOOTING article in GENERAL INFORMATION.

Inspection

1. Thoroughly clean gasket material from cylinder block and cylinder head mating surfaces. Using a straight edge and feeler gauge, check cylinder head sealing surface for warpage. Check cylinder head intake and exhaust manifold sealing surfaces for warpage. Replace cylinder head if warpage exceeds specification. See «CYLINDER HEAD»(ref-131978-S01189885142002010500000) table under ENGINE SPECIFICATIONS.
2. Check intake and exhaust manifold sealing surfaces for warpage. Replace manifold if warpage exceeds specification. See «MANIFOLD WARPAGE SPECIFICATIONS»(ref-131978-S25231735722002010500000) table. MANIFOLD WARPAGE SPECIFICATIONS Application Maximum Warpage - In. (mm) Exhaust Manifold .0197 (.500) Intake Manifold .0059 (.150)
3. Using a dye penetrant, check cylinder head sealing surface, and intake and exhaust ports for cracks. If cracked, replace cylinder head. Using outside calipers, measure cylinder head bolt diameter above bolt threads. Replace cylinder head bolt if diameter is less than .3819" (9.70 mm).
4. Inspect cylinder block deck surface for warpage. Replace cylinder block if deck warpage exceeds specification. See «CYLINDER BLOCK»(ref-131978-S07239423202002010500000) table under ENGINE SPECIFICATIONS. Inspect camshaft and components. See «CAMSHAFT»(ref-131978-S29833318072002010500000) .
5. Using a valve guide bushing brush and cleaning solvent, clean valve guides. Using an inside caliper gauge, measure inside diameter of valve guides. Using an outside micrometer, measure outside diameter of valve stems. Using the 2 measurements, determine valve guide oil clearance. If clearance is not within specification, replace valve and/or valve guide. See «CYLINDER HEAD»(ref-131978-S01189885142002010500000) under ENGINE SPECIFICATIONS.
6. Inspect valve lifters for damage. Measure outside diameter of valve lifter and inside diameter of valve lifter bore in cylinder head to determine valve lifter oil clearance. If clearance is not within specification, replace components as necessary. See «VALVE LIFTERS»(ref-131978-S21248805762002010500000) table under ENGINE SPECIFICATIONS.

Scheme 7

1. Using Valve Stem Oil Seal Replacer (09201-41020), install valve stem oil seals onto valve guides. Install valves, valve spring seats, valve springs, spring retainers and keepers.
2. Install NEW exhaust manifold gaskets on cylinder head, so White paint mark on gasket faces exhaust manifold. Install exhaust manifolds. Install NEW exhaust manifold nuts and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000). Install heat insulators.
3. Rear side of cylinder head gaskets are marked "3R" and "3L" to distinguish right and left banks. Install NEW cylinder head gasket on correct side of cylinder block. Position cylinder heads on cylinder block over locating dowels in block.
4. Apply light coat of oil to threads and underside of cylinder head bolts. Install washers on cylinder head bolts. Install cylinder head bolts and tighten to specification in 2 steps, in sequence. (Scheme 7) See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000).
5. Install body ground leads to rear of cylinder heads. Install wire harness brackets to cylinder heads. Connect 2 heated oxygen sensor harness connectors. Install valve lifters and adjusting shims.
6. Install camshafts. See «CAMSHAFT»(ref-131978-S29833318072002010500000). To avoid valve/piston interference, position crankshaft pulley timing mark with center of crankshaft pulley bolt and center of No. 2 timing belt idler pulley bolt. see scheme 7 Check and adjust valve clearance. See «VALVE CLEARANCE ADJUSTMENT»(ref-131978-S40606395472002010500000) under ADJUSTMENTS. NOTE: There are 2 half-circular camshaft plugs for each cylinder head. Ensure both half-circular plugs are installed in each cylinder head.
7. Apply a continuous bead of silicone sealant to mating surface of plug before installation. Install 4 half-circular camshaft plugs to cylinder head.
8. Apply silicone sealant to outer edges of front camshaft bearing caps at cylinder head. Install NEW gaskets onto valve covers. Install valve covers. Install seal washers and valve cover bolts. Tighten bolts evenly to specification, in several passes. See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000).
9. Install wire harness clamp bracket to right front camshaft bearing cap. Install engine hangers, VVT sensors, and camshaft timing oil control valve. Install engine and transmission oil dipstick guide tubes.
10. Using NEW gaskets, install front and rear water manifolds. Tighten nuts alternately to specification. See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000). Connect coolant hoses to water manifolds. Connect engine coolant temperature sensor. Using a NEW "O" ring, install water by-pass pipe to water pump. Connect heater hose to water by-pass pipe.
11. Using NEW gaskets and nuts, install 2 TWC's to exhaust manifolds. Install front exhaust pipe to the 2 TWC's. Install power steering pump. Install timing belt rear plates to cylinder heads. Install camshaft position sensor. Install camshaft sprockets. Install timing belt. See «TIMING BELT»(ref-131978-S15835946542002010500000).
12. Install NEW intake manifold gaskets onto cylinder heads, with White paint mark on gaskets facing upward. Ensure holes in gasket align with holes in cylinder head. Install intake manifold assembly onto cylinder heads. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000).
13. Connect 8 injector harness connectors. Install wire harness retainers. Connect EVAP hoses. Connect all wire harness connectors, emission, coolant and vacuum hoses removed. Connect fuel lines. Install throttle body. Connect and adjust accelerator cable.
14. Install radiator assembly. Install intake air duct and air cleaner assembly. Fill engine with coolant. Check engine oil level. Connect negative battery cable. Start engine and check for coolant and fuel leaks. Bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-131978-S36299518652002010500000) under ADJUSTMENTS.
15. Install engine under cover. Install engine "V" bank and side covers.

Note. DO NOT bend, twist or turn timing belt inside out. DO NOT allow timing belt to come into contact with oil, water or coolant. DO NOT allow any timing belt tension when installing or removing camshaft sprocket retaining bolts.

1. Inspect timing belt for damaged teeth, cracking or oil contamination. Replace timing belt if damaged or contaminated. Check idler pulleys for smooth rotation and signs of grease leakage. Replace idler pulleys if defective.
2. Inspect timing belt tensioner for signs of oil leakage. Replace timing belt tensioner if oil leakage exists. Hold timing belt tensioner body so tension rod is facing upward, and press rod against a solid surface. Replace timing belt tensioner if tension rod moves. NOTE: Timing belt tensioner may weep a small amount of oil on rod seal under normal conditions. If excessive amount of oil exists, replace timing belt tensioner.
3. Measure timing belt tensioner rod protrusion from end of rod to edge of housing. (Scheme 8) Replace timing belt tensioner if rod does not protrude.374-.413" (9.50-10.49 mm) above housing. Inspect water pump for leakage and smooth shaft rotation, and replace as necessary.
4. Using a press, slowly press timing belt tensioner rod down until hole in tension rod aligns with hole in housing. Insert a small hexagon (Allen) wrench through holes to lock tension rod down for installation purposes. (Scheme 9)

Scheme 8

Scheme 9

Inspect components for damage. Measure valve lifter diameter and lifter bore diameter in cylinder head to determine lifter clearance. Ensure oil clearance is within specification. Replace components if not within specification. See VALVE LIFTERS table under ENGINE SPECIFICATIONS.

1. Inspect components for defects and damage. Check camshaft journal outside diameter, lobe height and journal runout. Replace camshaft if not within specification. See «CAMSHAFT»(ref-131978-S34847070992002010500000) table under ENGINE SPECIFICATIONS.
2. To check journal oil clearance, install camshafts in cylinder head one at a time, without lifters. Using Plastigage, check camshaft oil clearance. Tighten camshaft bearing cap bolts to specification, in sequence. See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000). see scheme 23 DO NOT turn camshaft.
3. Remove camshaft, and check thickness of Plastigage to determine oil clearance. Replace camshaft and/or cylinder head and bearing caps if oil clearance is not within specification. See «CAMSHAFT»(ref-131978-S34847070992002010500000) table under ENGINE SPECIFICATIONS.
4. Check camshaft end play with camshaft bearing cap bolts tightened to specification. Replace camshaft and/or cylinder head and bearing caps if end play is not within specification. See «CAMSHAFT»(ref-131978-S34847070992002010500000) table under ENGINE SPECIFICATIONS. NOTE: Camshaft end play thrust is determined by front bearing cap installation.
5. Install both camshafts in cylinder head without sub-gear installed on exhaust camshaft. Tighten camshaft bearing cap bolts to specification, in sequence. see scheme 23 See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000). Check gear backlash between camshaft gears.
6. Replace intake camshaft drive gear and exhaust camshaft if gear backlash exceeds specification. See «CAMSHAFT»(ref-131978-S34847070992002010500000) table under ENGINE SPECIFICATIONS. Measure distance (gap) between ends of gear spring. Replace gear spring if distance is not 0.712-0.740" (18.0-18.8 mm).

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. Ensure timing mark on crankshaft pulley is aligned with center of crankshaft pulley bolt and center of No. 2 timing belt idler pulley bolt. see scheme 7 To install camshafts in RH cylinder head, apply grease to thrust surfaces of intake and exhaust camshafts. Install intake and exhaust camshafts in RH cylinder head so timing marks on sprockets align with each other. see scheme 2 Rotate camshaft and position timing mark (one dot) of camshaft main gear at a 10-degree angle above mating position of timing marks on both camshaft gears.
2. Install camshaft housing plug to cylinder head (if removed). Install camshaft oil control valve filter to RH cylinder head. Apply silicone sealant to front bearing cap as shown. (Scheme 11) Install front bearing cap. Install remaining camshaft bearing caps in their proper order from front to rear, with arrows on caps pointing forward. (Scheme 12) Push in front camshaft oil seal.
3. Identify camshaft bearing cap bolts. See «CAMSHAFT BEARING CAP BOLT SPECIFICATIONS»(ref-131978-S11416204852002010500000). Install NEW seal washers to bearing cap bolts "A" and "B". Coat threads and under heads of bearing cap bolts "D" and "E". (Scheme 13) DO NOT apply engine oil under heads of bearing cap bolts "A", "B" and "C". Install oil feed pipe. Install bearing cap bolts in their correct location. (Scheme 13) Tighten bearing cap bolts to specification in several steps, in the proper sequence. see scheme 23 See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000). CAMSHAFT BEARING CAP BOLTS SPECIFICATIONS Bolt (1) Length - In. (mm) "A" 3.7007 (94.000) "B" 2.8346 (72.000) "C 0.9842 (24.990) "D" 2.0472 (51.999) "E" 1.4960 (37.998) (1) (Scheme 13)
4. To install camshafts in LH cylinder head, apply grease to thrust surfaces of exhaust and intake camshafts. Install camshafts in LH cylinder head. Rotate camshafts and align timing marks (one dot) on each gear with each other. see scheme 2 Install camshaft housing plug to cylinder head (if removed). Install camshaft oil control valve filter to LH cylinder head. Apply silicone sealant to front bearing cap as shown. (Scheme 11) Install front bearing caps. Install remaining bearing caps in their proper location from front to rear, with arrow mark facing forward. (Scheme 12) Push in front camshaft oil seal.
5. Identify camshaft bearing cap bolts. See «CAMSHAFT BEARING CAP BOLT SPECIFICATIONS»(ref-131978-S11416204852002010500000) table. Install NEW seal washers to bearing cap bolts "A" and "B". Coat threads and under heads of bearing cap bolts "D" and "E". (Scheme 13) DO NOT apply engine oil under heads of bearing cap bolts "A", "B" and "C". Install oil feed pipe. Install bearing cap bolts in their correct location. (Scheme 13) Tighten bearing cap bolts to specification in several steps, in the proper sequence. see scheme 23 See «TORQUE SPECIFICATIONS»(ref-131978-S04317680092002010500000).
6. Remove service bolt from exhaust camshaft gears. To install remaining components, reverse removal procedure. Check valve clearance. See «VALVE CLEARANCE ADJUSTMENT»(ref-131978-S40606395472002010500000) under ADJUSTMENTS. Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-131978-S36299518652002010500000).

1. Inspect components for damage. Coat relief valve with engine oil. Ensure relief valve slides freely in valve bore. Install drive and driven rotors in oil pump body, with identification mark (triangle mark) facing toward oil pump cover.
2. Using a feeler gauge, measure driven rotor-to-oil pump body clearance. Replace rotor assembly or oil pump assembly if clearance exceeds specification. See «OIL PUMP SPECIFICATIONS»(ref-131978-S41120910082002010500000) table.
3. Measure rotor tip clearance between tips of rotors. Replace rotor assembly if clearance exceeds specification. See «OIL PUMP SPECIFICATIONS»(ref-131978-S41120910082002010500000) table.
4. Place straightedge across oil pump body, above both rotors. Using a feeler gauge, measure rotor end clearance (side clearance) between straightedge and surface of each rotor. Replace rotor assembly or oil pump assembly if clearance exceeds specification. See «OIL PUMP SPECIFICATIONS»(ref-131978-S41120910082002010500000) table.

OIL PUMP SPECIFICATIONS