engine

Head Gasket - Single

for 2021 Toyota RAV4 2.5L I4 · AWD

Difficulty

Expert

Time

12.6 h

Tools

Steps

This procedure covers the removal and replacement of the cylinder head gasket on the 2019-2024 Toyota RAV4 with the 2.5L I4 gasoline engine, including timing chain removal, valve train disassembly, and head resurfacing preparation.

Warnings

⚠️Engine must be completely cold before starting work. Hot coolant and components can cause severe burns.

⚠️The timing chain must be properly secured and aligned. Incorrect timing will cause severe engine damage upon startup.

⚠Cylinder head bolts are torque-to-yield (TTY) and must be replaced with new bolts. Reusing old bolts will result in improper clamping and gasket failure.

⚠The cylinder head should be inspected for warpage using a straight edge and feeler gauge. Maximum warpage is 0.05mm (0.002 in). Resurfacing may be required.

ℹ️This engine uses a timing chain, not a belt. Maintain timing chain tension throughout the procedure to prevent timing position loss.

Tools required

Toyota engine support fixture or engine hoistEssential

Torque wrench (10-100 Nm range)Essential

Torque angle gaugeEssential

Timing chain holding toolEssential

Camshaft timing tool set (Toyota SST or equivalent)Essential

Coolant drain pan (large capacity)Essential

Socket set (metric, 8mm-19mm)Essential

Straight edge and feeler gauge (for head inspection)Essential

Engine oil drain panEssential

RTV gasket remover/scraper

Shop vacuum

Parts organizer/labeled bags

Parts

Cylinder head gasket × 1 — Use OEM Toyota specification
Cylinder head bolts (TTY - replace mandatory) × 10 — Use OEM Toyota specification
Valve cover gasket × 1 — Use OEM Toyota specification
Timing chain cover gasket × 1 — Use OEM Toyota specification
Timing chain tensioner gasket × 1 — Use OEM Toyota specification
Exhaust manifold gasket × 1 — Use OEM Toyota specification
Intake manifold gasket × 1 — Use OEM Toyota specification
Engine oil filter × 1 — Use OEM Toyota specification
Camshaft seal (front) × 2 — Use OEM Toyota specification
Water pump O-ring × 1 — Use OEM Toyota specification

Fluids

Toyota Genuine 0W-20 Engine Oil — 5 qt
Toyota Super Long Life Coolant (Pink) — 10 qt

Preparation

Ensure engine is completely cold (minimum 2 hours after last operation)
Disconnect negative battery terminal and wait 90 seconds for airbag system to discharge
Remove engine cover (pull upward to disengage clips)
Drain engine coolant completely from radiator drain cock and engine block drain plug
Drain engine oil and remove oil filter
Remove air intake assembly from air filter box to throttle body
Label and disconnect all electrical connectors, vacuum lines, and hoses attached to cylinder head
Support engine from above using engine support fixture or hoist - front mount will be removed
Remove right-hand engine mount to provide access to timing cover

Procedure

1
Remove exhaust manifold assembly
Disconnect oxygen sensor connectors. Remove exhaust manifold heat shield. Remove exhaust manifold nuts in reverse of tightening sequence (outside to inside). Separate exhaust manifold from cylinder head and catalytic converter. Remove and discard exhaust manifold gasket.
2
Remove intake manifold
Disconnect throttle body connectors and coolant hoses. Remove fuel rail (relieve fuel system pressure first by removing fuel pump relay and cranking engine). Disconnect all vacuum lines and PCV hoses from intake manifold. Remove intake manifold bolts in reverse sequence (outside to inside). Lift intake manifold away and remove gasket.
⚠️Fuel system is under pressure. Relieve pressure before disconnecting fuel lines to prevent fuel spray and fire hazard.
3
Remove valve cover assembly
Disconnect ignition coil connectors and remove all four ignition coils. Remove PCV hoses and ventilation hoses from valve cover. Remove valve cover bolts in reverse sequence (outside to inside). Carefully remove valve cover - use gentle prying if stuck, do not damage mating surface. Remove and discard valve cover gasket.
4
Remove timing chain cover and set timing marks
Remove crankshaft pulley bolt (use holding tool to prevent rotation). Remove timing chain cover bolts and carefully pry cover away. Rotate crankshaft to TDC on cylinder #1 (timing marks aligned on crankshaft and camshaft sprockets). Mark timing chain position relative to sprockets with paint pen. Install timing chain holding tool to maintain tension and position.
⚠Timing marks MUST be verified and chain position marked before proceeding. Take photos for reference during reassembly.
5
Remove timing chain tensioner and guides
Remove timing chain tensioner (it is spring-loaded, control carefully). Remove timing chain guide bolts and guides. Keep timing chain supported and secured to prevent losing timing position. Do not allow chain to fall into timing cover area.
6
Remove camshaft sprockets and timing chain
Hold camshafts using wrench on hex portion (do not use chain for holding). Remove camshaft sprocket bolts. Carefully remove both camshaft sprockets while supporting timing chain. Remove timing chain while keeping it secured to prevent dropping into engine. Secure chain to prevent falling.
7
Remove camshaft assemblies
Loosen camshaft cap bolts in multiple passes in reverse sequence (inside to outside, 1/4 turn each pass) to gradually release valve spring pressure. Remove all camshaft caps in order (they are numbered and directional - mark if unclear). Lift camshafts out and store in clean area. Keep caps organized by position.
⚠Camshaft caps must be loosened gradually in sequence to prevent warping. Sudden release of valve spring pressure can bend camshafts.
8
Remove cylinder head bolts and head
Remove cylinder head bolts in reverse sequence (outside to inside, starting from ends working to center) in multiple passes. Once all bolts are loose, remove and discard all head bolts (they are TTY and must not be reused). Carefully lift cylinder head straight up off engine block - it may be stuck due to gasket seal. If stuck, gently tap with soft mallet on casting boss areas only. Never pry between head and block mating surfaces.
⚠Do not damage head or block mating surfaces. Never insert pry tools between machined surfaces.
9
Inspect and clean surfaces
Remove and discard old head gasket. Thoroughly clean all gasket material from cylinder head and engine block mating surfaces using plastic scraper (never metal). Clean with brake cleaner or gasket remover. Inspect cylinder head surface with straight edge and feeler gauge - maximum warpage is 0.05mm (0.002 in). Check head for cracks. Inspect block surface similarly. Have head professionally resurfaced if warped beyond specification.
ℹ️Use only plastic scrapers on aluminum surfaces. Metal scrapers will gouge the soft aluminum and cause sealing problems.
10
Install new head gasket and cylinder head
Ensure block surface is completely clean and dry. Install new head gasket on block with 'TOP' or 'UP' mark facing cylinder head side. Verify dowel pins are in place. Carefully lower cylinder head onto block, aligning with dowel pins. Install NEW cylinder head bolts (do not reuse old TTY bolts) hand-tight in proper sequence.
⚠Head gasket orientation is critical. Verify TOP marking is facing up toward cylinder head before installation.
11
Torque cylinder head bolts
Torque cylinder head bolts in proper sequence (center outward): Step 1 - Torque all bolts to 36 Nm (27 lb-ft). Step 2 - Mark each bolt head position, then rotate each bolt an additional 90 degrees in sequence. Step 3 - Rotate each bolt another 90 degrees in sequence (total 180 degrees beyond initial torque). Verify final angle using torque angle gauge.
⚠Use only NEW head bolts. Angle torque must be precise - use a proper torque angle gauge, not visual estimation.
Torque spec
Cylinder Head Bolts - Step 140 Nm (30 lb-ft)
12
Install camshafts and caps
Apply clean engine oil to all camshaft journals and lobes. Install camshafts in correct positions (intake and exhaust are different). Ensure camshaft timing marks are positioned for TDC cylinder #1. Apply light oil to cap journals. Install camshaft caps in correct positions (numbered and directional). Tighten cap bolts in multiple passes in proper sequence (inside to outside, crossing pattern) to specification.
13
Install timing chain and components
Route timing chain onto crankshaft sprocket. Install camshaft sprockets with chain, aligning timing marks to marks made during disassembly. Verify all timing marks align correctly at TDC. Install and torque camshaft sprocket bolts while holding camshafts. Install timing chain guides. Install new timing chain tensioner. Rotate engine two complete revolutions and verify timing marks realign correctly.
⚠️Verify timing marks alignment before proceeding. Incorrect timing will destroy engine upon startup.
14
Install timing cover and valve cover
Install new timing chain cover gasket and/or apply RTV sealant per factory specification. Install timing cover and torque bolts. Install crankshaft pulley and torque bolt. Install new valve cover gasket (no RTV needed unless specified). Install valve cover and torque bolts in sequence (center outward). Install ignition coils.
15
Install intake and exhaust manifolds
Install new intake manifold gasket. Position intake manifold and install bolts finger-tight. Torque intake manifold bolts in sequence (center outward) to specification. Reconnect fuel rail, vacuum lines, and all connectors. Install new exhaust manifold gasket. Install exhaust manifold and torque nuts in sequence (inside to outside) to specification. Reconnect oxygen sensors.
Torque spec
Intake Manifold Bolts25 Nm (18 lb-ft)
Exhaust Manifold Nuts25 Nm (18 lb-ft)

Reassembly

Reinstall right-hand engine mount and remove engine support fixture
Reconnect all electrical connectors, vacuum lines, and coolant hoses per labels made during disassembly
Install new oil filter and refill engine with 5.0 quarts Toyota Genuine 0W-20 oil
Refill cooling system with 10.0 quarts Toyota Super Long Life Coolant (Pink) - bleed air from system
Reinstall air intake assembly and engine cover
Reconnect battery negative terminal

Verification

With ignition off, verify engine rotates freely by hand (crankshaft pulley should turn smoothly)
Perform initial start with observer watching for leaks - keep run time under 30 seconds for first start
Check for coolant, oil, and fuel leaks around all disturbed components
Allow engine to reach operating temperature and verify cooling fans cycle properly
Check coolant level after engine cools and top off as needed - burp cooling system of air
Verify no check engine lights or timing-related fault codes are present
Road test vehicle and verify normal engine performance, no misfires, and proper power delivery
Re-check all fluid levels and inspect for leaks after 50-100 miles of operation