Engine Mechanical (3.4L V6): Other Toyota 4Runner III

FUEL PRESSURE RELEASE

1. Disconnect electrical connector from top of electric fuel pump. Electric fuel pump is located in fuel tank with electrical connector located on top of fuel tank.
2. Start engine and allow engine to idle until engine stalls. Turn ignition off. Reconnect electrical connector for electric fuel pump. Disconnect negative battery cable.
3. Place suitable container under fuel line connection. Cover fuel line connection with shop towel. Slowly loosen fuel line connection, allowing fuel pressure to be released. Once fuel pressure is released, fuel system components may be serviced.

Scheme 67

Scheme 68

1. Engine and transmission are removed as an assembly. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-8778-S22545962682000092200000) . Drain cooling system, engine oil and transmission fluid. Remove hood.
2. Remove front grill for access to radiator. Disconnect necessary hoses and oil cooler lines for removal of radiator. Remove radiator. Remove fan clutch-to-fan bracket nuts. Remove radiator cooling fan with fan clutch and pulley from fan bracket.
3. Disconnect accelerator, throttle and cruise control cables. Disconnect heater hoses from engine. Disconnect brake booster hose, EVAP hose, fuel return and fuel inlet hoses. Mark and disconnect appropriate wiring and connectors for engine removal.
4. Disconnect starter ground strap. Disconnect positive battery cable. Remove 2 starter cable clamps. Disconnect starter wire connector. Disconnect wire from relay block No. 2. Disconnect generator wire.
5. Remove glove compartment door and lower finish panel to access Engine Control Module (ECM). Disconnect all ECM connectors. Disconnect 2 wiring clamps from finish panel.
6. Disconnect remaining clamps and wiring connectors for engine wiring harness from under instrument panel. Pull engine wiring harness into engine compartment.
7. Raise and support vehicle. Remove lower engine cover. Place references marks on drive shaft flange at rear differential for reassembly reference. Remove drive shaft flange-to-rear differential flange bolts/nuts and drive shaft. Install special cover in transmission to prevent fluid leak.
8. Remove bolts/nuts, front exhaust pipe support bracket, front exhaust pipe and gaskets. Front exhaust pipe contains catalytic converter and is located between crossover pipe between exhaust manifolds and rear exhaust pipe to muffler.
9. Support transmission with jack. Remove bolts holding rear mount bracket to crossmember. Install appropriate engine lift. Attach lifting chains only to provided hangers. Carefully lift engine and transmission from vehicle.

CAMSHAFT

Note. When servicing camshafts, reference to right and left components are as viewed from rear (flywheel end) of engine.

Scheme 69

Scheme 70

Scheme 71

1. For access to valve covers, air intake chamber and intake air connector must be removed. see scheme 11
2. Mark and disconnect necessary fuel and electrical connectors, control cables, vacuum hoses and coolant hoses for access to valve covers. Remove bolts, seal washers, valve covers and gaskets.
3. Remove timing belt and camshaft sprockets. See «TIMING BELT»(ref-8778-S32319182122000092200000). Remove camshaft position sensor. CAUTION: Since thrust clearance of camshaft is small, keep camshaft level during removal and installation or cylinder head at thrust end may be damaged and/or camshaft may be damaged.
4. To service camshafts in right cylinder head, align timing marks with 2 dots on camshaft gears by rotating camshaft using hexagonal area of camshaft. (Scheme 69) To service camshafts in left cylinder head, align timing marks with one dot on camshaft gears by rotating camshaft using hexagonal area of camshaft. (Scheme 69)
5. On all applications, secure camshaft sub-gear on exhaust camshaft to main gear with a 6 x 1.0 x 18-mm service bolt. (Scheme 70) Before removing camshaft bearing cap bolts, ensure torsional spring force of camshaft sub-gear is held by service bolt. NOTE: Camshaft bearing caps are numbered for location on top of camshaft bearing cap. Camshaft bearing cap is also stamped with either an "I" for intake camshaft or an "E" for exhaust camshaft. Arrow on top of camshaft bearing cap must point the proper direction in accordance with cylinder head application. (Scheme 71) Camshaft bearing caps must be installed in correct location.
6. Note location of camshaft bearing caps, as camshaft bearing caps are numbered for location on top of camshaft bearing cap. Camshaft bearing cap is also stamped with either an "I" for intake camshaft or an "E" for exhaust camshaft. Arrow on top of camshaft bearing cap must point the proper direction in accordance with cylinder head application. (Scheme 71) CAUTION: Camshaft bearing cap bolts must be removed in proper sequence to prevent damage to cylinder head and camshaft thrust surfaces.
7. Remove exhaust camshaft bearing cap bolts in sequence using several steps. (Scheme 72) Remove camshaft bearing caps and exhaust camshaft.
8. Remove intake camshaft bearing cap bolts in sequence using several steps. (Scheme 72) Remove camshaft bearing caps, intake camshaft and oil seal.
9. If disassembling exhaust camshaft, mount hexagonal area of camshaft in soft-jaw vise. Using spanner wrench, rotate camshaft sub-gear clockwise and remove service bolt. (Scheme 73) Remove snap ring, wave washer, camshaft sub-gear and camshaft gear spring. see scheme 13

Scheme 72

Scheme 73

Cylinder Head

1. Thoroughly clean cylinder head of carbon and gasket material. Inspect cylinder head warpage at cylinder block and manifold surfaces. Replace cylinder head if warpage exceeds specification. See «CYLINDER HEAD»(ref-8778-S39709470642000092200000) table under ENGINE SPECIFICATIONS. Use dye penetrant spray to check for cracks.
2. To check camshaft oil clearance using Plastigage, install camshaft in cylinder head using proper procedure. See «CAMSHAFT»(ref-8778-S34285317822000092200000) .
3. Replace camshaft and/or cylinder head if oil clearance is not within specification. See «CAMSHAFT»(ref-8778-S20073811082000092200000) table under ENGINE SPECIFICATIONS.
4. Check camshaft end play with camshaft bearing cap bolts tightened to specification. Replace camshaft and/or cylinder head if camshaft end play is not within specification. See «CAMSHAFT»(ref-8778-S20073811082000092200000) table under ENGINE SPECIFICATIONS.
5. Measure valve lifter diameter and lifter bore diameter. Ensure oil clearance is within specification. Replace components if not within specification. See «VALVE LIFTERS»(ref-8778-S16211561882000092200000) table under ENGINE SPECIFICATIONS.
6. If installing spark plug tubes in NEW cylinder head, apply sealant on cylinder head end of spark plug tube. Using press, install spark plug tube until distance between top surface of spark plug tube and camshaft bearing cap surface on cylinder head is 1.929-1.945" (48.99-49.40 mm).

Valve Springs

Ensure valve spring free length, pressure and out-of-square are within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Replace valve spring if not within specification.

Valve Stem Oil Seals

Lubricate valve stem oil seal with engine oil. Install valve stem oil seal using oil seal installer.

Valve Guides

1. Ensure valve guide inside diameter is within specification. See «CYLINDER HEAD»(ref-8778-S39709470642000092200000) table under ENGINE SPECIFICATIONS. Replace valve guide if inside diameter exceeds specification.
2. To replace valve guide, wrap tape around stem of an old valve, about .315" (8.00 mm) from end of valve stem. From top of cylinder head, insert old valve into valve guide until tape area rests on valve guide.
3. Using hammer, hit old valve to break off top of old valve guide. Remove snap ring from valve guide. Heat cylinder head to 176-212°F (80-100°C). Using hammer and valve guide remover/installer, drive valve guide from camshaft side of cylinder head.
4. Measure cylinder head valve guide bore inside diameter. If bore inside diameter is .4325-.4341" (10.985-11.026 mm), use standard valve guide. If bore inside diameter is .4350-.4361" (11.049-11.076 mm), use oversize valve guide.
5. If bore inside diameter exceeds .4341" (11.026 mm), machine valve guide bore to .4350-.4361" (11.049-11.076 mm) for oversize valve guide. If bore I.D. exceeds .4361" (11.076 mm), replace cylinder head.
6. To install valve guide, heat cylinder head to 176-212°F (80-100°C). Using hammer and valve guide remover/installer, drive valve guide in from camshaft side of cylinder head until snap ring on valve guide contacts cylinder head.
7. Using .236" (5.99 mm) reamer, ream valve guide to obtain specified valve stem-to-guide oil clearance. See «CYLINDER HEAD»(ref-8778-S39709470642000092200000) table under ENGINE SPECIFICATIONS.

Valve Seat

Ensure valve seat angle and seat width are within specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. Valve seat replacement information is not available from manufacturer.

Valves

Ensure minimum refinish length, stem diameter and valve margin are within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Replace valve if not within specification.

Valve Seat Correction Angles

Use 30-degree and 45-degree stones to lower valve seat contact area. Use 60-degree and 45-degree stones to raise valve seat contact area.

Valve Lifters

Ensure valve lifter diameter, bore diameter and oil clearance are within specification. See VALVE LIFTERS table under ENGINE SPECIFICATIONS. Replace components if not within specification.

Fitting Pistons

1. Different piston sizes and cylinder bore sizes are used. Piston diameter is determined by size mark ("1", "2" or "3") stamped on top of piston. see scheme 35 Cylinder bore diameter is determined by cylinder bore size mark ("1", "2" or "3") on cylinder block deck surface. (Scheme 74)
2. To determine piston-to-cylinder bore clearance, measure piston diameter and cylinder bore diameter. Measure piston skirt diameter at 1.02" (25.9 mm) from top of piston at 90-degree angle to piston pin. Measure cylinder bore diameter at 2 different places, 90 degrees apart at.39" (9.9 mm) from top and bottom of cylinder bore and at middle of cylinder bore.
3. Ensure piston diameter and cylinder bore diameter are within specification. See «PISTONS, PINS & RINGS»(ref-8778-S08151175252000092200000) and «CYLINDER BLOCK»(ref-8778-S02080623672000092200000) tables under ENGINE SPECIFICATIONS.
4. Calculate piston-to-cylinder clearance. Replace pistons or bore cylinder block for oversize pistons if clearance exceeds specification. See «PISTONS, PINS & RINGS»(ref-8778-S08151175252000092200000) table under ENGINE SPECIFICATIONS. Pistons are available in.020" (.50 mm) oversize. If replacing piston, ensure replacement piston contains same size mark as cylinder bore size mark on cylinder block.

Scheme 74

Piston Rings

Ensure piston ring end gap and side clearance are within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. Position piston rings with ring end gaps in proper areas and with identification mark on piston ring toward top of piston. (Scheme 75)

Note. No. 1 compression ring may contain a 1R or "T" identification mark and No. 2 compression ring may contain a 2R or 2T identification mark. Ensure proper ring is installed in correct location.

Scheme 75

Rod Bearings

1. Ensure connecting rod and connecting rod cap are marked with matching cylinder number for installation reference. Piston and connecting rod and connecting rod cap must be installed in cylinder block with front mark facing timing belt end of engine. see scheme 35
2. Connecting rod cap and rod bearing are stamped with size mark ("1", "2" or "3"). (Scheme 76) Size marks on connecting rod cap and rod bearing must be the same. Rod bearing thickness is determined by size mark. See «ROD BEARING SPECIFICATIONS»(ref-8778-S30318369282000092200000) table. NOTE: If replacing rod bearing, ensure size mark on replacement rod bearing is the same as size mark on original rod bearing. Size mark must also be the same as that stamped on connecting rod cap.
3. Ensure nut rotates easily on connecting rod bolt. If nut does not rotate easily, use caliper to measure outside diameter of connecting rod bolt at threaded area.59" (14.9 mm) from end of connecting rod bolt. Replace connecting rod with connecting rod bolt and nut as an assembly if outside diameter is less than.2992" (7.599 mm).
4. Ensure piston and connecting rod are installed in cylinder block with front mark on piston, and front mark (protrusion) on connecting rod cap facing timing belt end of engine. see scheme 35
5. Coat threads of connecting rod bolts and nut-to-connecting rod cap contact surface with engine oil before tightening to specification. See «TORQUE SPECIFICATIONS»(ref-8778-S21926401902000092200000).
6. Ensure bearing oil clearance and connecting rod side play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-8778-S38751770812000092200000) and «CONNECTING RODS»(ref-8778-S15489807582000092200000) tables under ENGINE SPECIFICATIONS.

ROD BEARING SPECIFICATIONS

Scheme 76

Scheme 77

1. Note direction of front mark (arrow) on main cap for reassembly reference. (Scheme 77)
2. Remove main bearing cap bolts in sequence using several passes. (Scheme 77) Remove main bearing cap, crankshaft, main bearings and thrust bearings.
3. Cylinder block main bearing bore inside diameter is determined by main bearing bore size mark ("1", "2" or "3") stamped on rear of cylinder block. (Scheme 78) Crankshaft main bearing journal diameter is determined by main bearing journal size mark ("0", "1" or "2") located on crankshaft counterweight. (Scheme 78)
4. Ensure journal diameter, taper and out-of-round are with within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-8778-S38751770812000092200000) table under ENGINE SPECIFICATIONS.
5. Main bearing size mark ("1", "2", "3", "4" or "5") is located on side of main bearing. (Scheme 78) If replacing main bearing, ensure size mark on replacement main bearing is the same as size mark on original main bearing.
6. If main bearing size mark on original main bearing cannot be obtained, add main bearing bore size mark on cylinder block and main bearing journal size mark on crankshaft together to determine size mark of main bearing to be used. For example, if cylinder block contains a main bearing bore size mark of "2" and crankshaft journal has a size mark of "1", use a main bearing with the size mark of "3". Main bearing thickness is determined by main bearing size mark. See «MAIN BEARING SPECIFICATIONS»(ref-8778-S12302294272000092200000) table. MAIN BEARING SPECIFICATIONS Size Mark Bearing Thickness - In. (mm) No. 1 Main Bearing "1".07839-.07850 (1.9911-1.9939) "2".07850-.07862 (1.9939-1.9969) "3".07862-.07874 (1.9969-1.9999) "4".07874-.07886 (1.9999-2.0030) "5".07886-.07897 (2.0030-2.0058) Except No. 1 Main Bearing "1".07830-.07842 (1.9888-1.9918) "2".07842-.07854 (1.9918-1.9949) "3".07854-.07866 (1.9949-1.9979) "4".07866-.07878 (1.9979-2.0010) "5".07878-.07889 (2.0010-2.0038)
7. Use Plastigage to check main bearing oil clearance. Coat threads of main bearing cap bolts and bolt head-to-main bearing cap area with engine oil.
8. Install.87" (22.0 mm) wide main bearings in No. 1 main bearing at timing belt end of engine and.79" (20.0 mm) wide bearings in all other main bearings. Ensure all main bearings with oil holes are installed in cylinder block and lower main bearings installed in main bearing cap DO NOT have oil holes. CAUTION: Main bearing cap must be installed with front mark (arrow) on top of cap pointing toward timing belt end of engine. (Scheme 77)
9. Install thrust bearings on No. 2 main bearing in cylinder block and main bearing cap with grooved sides facing outward, toward crankshaft. Install crankshaft and main bearing cap.
10. Install and tighten main bearing cap bolts to specification in sequence using several steps. (Scheme 77) See «TORQUE SPECIFICATIONS»(ref-8778-S21926401902000092200000).
11. Ensure crankshaft end play and main bearing oil clearance are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-8778-S38751770812000092200000) table under ENGINE SPECIFICATIONS. Replace thrust bearing if crankshaft end play is not within specification.

Scheme 78

Thrust Bearing

Install thrust bearings on No. 2 main bearing in cylinder block and main bearing cap with grooved sides facing outward, toward crankshaft. Replace thrust bearing if crankshaft end play is not within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.

Cylinder Block

1. Inspect cylinder block deck surface warpage. Replace cylinder block if deck warpage exceeds specification. See «CYLINDER BLOCK»(ref-8778-S02080623672000092200000) table under ENGINE SPECIFICATIONS.
2. Different cylinder bore sizes are used. Cylinder bore diameter is determined by cylinder bore size mark ("1", "2" or "3") on cylinder block deck surface. (Scheme 74)
3. Measure cylinder bore diameter at 2 different places, 90 degrees apart at.39" (9.9 mm) from top and bottom of cylinder bore and at middle of cylinder bore. Ensure cylinder bore diameter is within specification. See «CYLINDER BLOCK»(ref-8778-S02080623672000092200000) table under ENGINE SPECIFICATIONS.
4. Bore cylinder block for oversize pistons if cylinder bore diameter exceeds specification. Pistons are available in.020" (.50 mm) oversize.
5. Ensure main bearing bore inside diameter is within specification with main bearing cap installed and bolts tightened to specification. See «CYLINDER BLOCK»(ref-8778-S02080623672000092200000) table under ENGINE SPECIFICATIONS. See «TORQUE SPECIFICATIONS»(ref-8778-S21926401902000092200000).

Note. Main bearing bore inside diameter is determined by main bearing bore size mark ("1", "2" or "3") stamped on rear of cylinder block. (Scheme 78)

Oil Pressure

With engine at normal operating temperature, oil pressure should be at least 4.3 psi (0.3 kg/cm 2 ) at idle and 36-75 psi (2.5-5.2 kg/cm 2 ) at 3000 RPM.