This procedure involves complete engine removal, disassembly, and replacement of main bearing shells in the 2.5L I4 engine block and crankshaft. This is a major internal engine overhaul requiring precise torque procedures and careful cleanliness.

Warnings

Tools required

Parts

• Main bearing set (standard or oversized as measured) × 1 — Use OEM specification based on crankshaft measurements
• Thrust bearing set × 1 — Use OEM specification
• Main cap bolts (replace if torque-to-yield) × 10 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Front engine cover gasket × 1 — Use OEM specification
• Rear main seal × 1 — Use OEM specification
• Complete engine gasket set × 1 — Use OEM specification
• Engine oil filter × 1 — Use OEM specification
• Coolant drain plug O-rings × 2 — Use OEM specification

Fluids

• Toyota Genuine 0W-20 engine oil — 5 qt
• Toyota Super Long Life Coolant (Pink) — 10 qt

Preparation

1. Disconnect negative battery terminal and wait 90 seconds for airbag system to discharge
2. Drain engine oil completely and remove oil filter
3. Drain engine coolant from radiator and block drain plugs
4. Remove engine cover and air intake assembly
5. Relieve fuel system pressure by removing fuel pump relay and cranking engine until it stalls
6. Disconnect all electrical connectors, fuel lines, coolant hoses, and vacuum lines from engine
7. Remove radiator, cooling fans, and A/C condenser (refrigerant recovery required)
8. Remove exhaust manifold and front exhaust pipe
9. Disconnect driveshafts from transmission and remove
10. Support transmission with jack and remove engine-to-transmission bolts
11. Attach engine hoist with chains to lifting points on engine
12. Remove engine mounting bolts and carefully extract engine from vehicle
13. Mount engine securely on engine stand
14. Organize workspace with clean surfaces for parts inspection and assembly

Procedure

1. 1

   Remove external engine components
   Remove all accessories from engine block: alternator, starter, A/C compressor, power steering pump (if equipped), water pump, thermostat housing, oil filter housing, and all sensors. Label and bag all bolts by component. Remove intake manifold and exhaust manifold if not already removed.
   Torque spec

   Mounting Bolts47 Nm (35 lb-ft)

   Sensor Bolts11 Nm (8 lb-ft)
2. 2

   Remove cylinder head
   Remove valve cover and timing chain cover. Remove timing chain, guides, and tensioners. Remove cylinder head bolts in reverse of tightening sequence (outside-in pattern). Lift cylinder head off and place on clean surface. Remove head gasket and inspect deck surface for warping or damage.
   Torque spec

   Cover Bolts16 Nm (12 lb-ft)
3. 3

   Remove pistons and connecting rods
   Rotate crankshaft to bring each piston to bottom dead center. Mark each connecting rod cap with cylinder number and orientation using permanent marker. Remove connecting rod cap bolts and carefully push piston/rod assemblies out through top of block. Store in order with caps matched to rods.
   ⚠Do not mix connecting rod caps. Each cap is matched to its specific rod and must be reinstalled in exact same position and orientation.
4. 4

   Mark and remove main bearing caps
   Inspect main bearing caps for factory markings indicating position and orientation (typically numbered 1-5 from front, with arrow pointing forward). If not marked, use permanent marker to clearly mark each cap number and orientation. Remove main cap bolts in sequence from outer caps working toward center. Carefully lift each cap straight up and store in order.
   ⚠️Main caps MUST be reinstalled in exact original positions and orientations. Mixing caps or installing backwards will cause immediate catastrophic engine failure.
   Torque spec

   Main Cap Bolts75 Nm (55 lb-ft) + 90°
5. 5

   Remove crankshaft and inspect journals
   Carefully lift crankshaft straight up out of engine block. Inspect all main bearing journals and connecting rod journals for scoring, discoloration, or damage. Measure each journal diameter with micrometer at multiple points. Record all measurements. Any journal out of specification requires crankshaft machining or replacement.
   ⚠Crankshaft is heavy (approximately 40 lbs). Use proper lifting technique to avoid injury or dropping.
6. 6

   Remove old bearings and clean surfaces
   Remove old bearing shells from main caps and engine block. Note thrust bearing location (typically center main). Clean all bearing saddles in block and caps with lint-free rags and brake cleaner. Remove all old oil and residue. Inspect bearing saddles for damage or scoring. Clean crankshaft journals thoroughly with clean solvent and dry completely.
   ⚠Bearing surfaces must be perfectly clean and dry. Any dirt, lint, or oil residue will cause bearing failure and engine damage.
7. 7

   Measure bearing clearances with Plastigage
   Install new bearing shells (dry, no oil) into block saddles and caps, ensuring tangs engage notches. Place strips of Plastigage on each crankshaft journal parallel to crank axis. Carefully install crankshaft. Install main caps in correct positions and orientations. Install main cap bolts and torque to 40 Nm (30 lb-ft) only - do NOT add the 90-degree turn yet. Remove caps without rotating crankshaft. Measure flattened Plastigage width using gauge on package. Clearance should be 0.025-0.050mm (0.001-0.002 inch). Record all clearances.
   ⚠Do not rotate crankshaft with Plastigage installed. This will give false readings and may damage bearings.
   ⚠If clearances are outside specification, determine if standard, 0.25mm, or 0.50mm undersize bearings are required based on crankshaft measurements.
   Torque spec

   Main Cap Bolts75 Nm (55 lb-ft) + 90°
8. 8

   Install final main bearings with oil
   Remove Plastigage residue from journals with clean rag. Install correct-size bearing shells into block and caps, ensuring tangs properly engage. Apply clean engine assembly lube or fresh 0W-20 oil to all bearing surfaces and crankshaft journals. Install crankshaft carefully into block. Verify thrust bearing is correctly positioned with oil grooves facing crankshaft journal.
   ℹ️Use only recommended engine assembly lube or clean engine oil. Do not use heavy grease that may block oil passages.
9. 9

   Install and torque main bearing caps
   Install each main bearing cap in correct position and orientation (numbers sequential 1-5 front to rear, arrows pointing forward). Install new main cap bolts if torque-to-yield type. Hand-tighten all bolts first. Torque main cap bolts in sequence from center bearing outward: First torque all bolts to 40 Nm (30 lb-ft). Then add additional 90 degrees of rotation to each bolt in same sequence using angle gauge. After torquing, verify crankshaft rotates smoothly by hand with no binding.
   ⚠️Main cap bolts require torque-to-yield procedure: 40 Nm THEN +90 degrees. Skipping angle portion will cause bolt failure and catastrophic engine damage.
   ⚠If crankshaft does not rotate smoothly after torquing, STOP. Remove caps and diagnose issue. Forcing rotation will destroy bearings.
   Torque spec

   Main Cap Bolts75 Nm (55 lb-ft) + 90°
10. 10

    Measure crankshaft endplay
    Using dial indicator mounted against crankshaft snout, measure crankshaft endplay by prying crankshaft forward and backward. Endplay should be 0.04-0.18mm (0.0016-0.0071 inch). If out of specification, verify correct thrust bearing installation or replace thrust bearing with correct oversized part.
    ⚠Incorrect endplay indicates thrust bearing problem. Operating engine with excessive endplay will cause thrust bearing failure and crankshaft damage.
11. 11

    Install pistons and connecting rods
    Install new connecting rod bearings with oil. Lubricate cylinder walls with engine oil. Install piston ring compressor on each piston. Install each piston/rod assembly into correct cylinder with markings facing forward. Ensure connecting rod cap is installed on correct rod in correct orientation. Torque connecting rod bolts to specification in service manual (typically torque-to-yield procedure similar to mains).
    ⚠Piston orientation is critical. Arrow or mark on piston crown must face forward (timing chain end) of engine.
12. 12

    Install oil pump and oil pan
    Install oil pump with new gasket if removed. Prime oil pump by filling with fresh engine oil or using priming tool. Clean oil pan and block mating surfaces thoroughly. Apply continuous bead of RTV silicone gasket maker (Toyota 08826-00080) to oil pan flange and install within 3 minutes. Install oil pan bolts and torque to specification.
    ℹ️RTV must cure for at least 2 hours before adding oil. Do not start engine before RTV cures or oil leaks will occur.
    Torque spec

    Gasket Bolts20 Nm (15 lb-ft)

    Gasket Surface Bolts20 Nm (15 lb-ft)
13. 13

    Reassemble engine and reinstall
    Install new head gasket (ensure correct orientation). Reinstall cylinder head and torque head bolts in proper sequence per service manual. Reinstall timing chain with correct cam timing marks aligned. Install timing cover with new gasket. Reinstall all external components, accessories, sensors, and manifolds using new gaskets. Remove engine from stand and reinstall into vehicle using hoist. Reconnect transmission, driveshafts, exhaust, cooling system, fuel system, and all electrical connections.
    ⚠️Timing chain must be installed with cam and crank timing marks precisely aligned. Incorrect timing will cause piston-to-valve contact and catastrophic engine damage.
    Torque spec

    Cover Bolts16 Nm (12 lb-ft)

    Mounting Bolts47 Nm (35 lb-ft)

    Electrical Connector Bolts7 Nm (5 lb-ft)

Reassembly

1. Double-check all electrical connectors are fully seated and locked
2. Verify all coolant hoses are properly clamped and fuel lines are secured
3. Ensure all ground straps are reconnected to engine block and body
4. Install new engine oil filter and fill with 5 quarts Toyota Genuine 0W-20 oil
5. Refill cooling system with 10 quarts Toyota Super Long Life Coolant (Pink), bleed air from system
6. Reconnect negative battery terminal

Verification

• Before starting engine, rotate crankshaft by hand at least two full revolutions to verify no interference or binding
• Check that all fluid levels are correct (oil, coolant, transmission)
• Start engine and immediately verify oil pressure light extinguishes within 2-3 seconds
• Listen for any abnormal knocking, ticking, or grinding noises that indicate bearing or assembly problems
• Allow engine to warm to operating temperature while monitoring for leaks (oil, coolant, fuel)
• Check for proper operation: smooth idle, no excessive vibration, normal oil pressure readings
• After initial 20-minute run, shut down and recheck all fluid levels, adding as necessary
• Road test vehicle to verify normal operation under load
• Perform first oil change after 500 miles to remove any assembly residue and verify no metal particles in oil
• Monitor oil pressure, temperature, and check for leaks during first 1000 miles of operation

More procedures for this vehicle