🔧 4Runner - Timing Belt Replacement (Timing Chain Service)

Your 4Runner’s 4.0L V6 uses a timing chain, not a timing belt—so there is no routine “timing belt replacement” interval. The chain is designed to last a long time, and replacement is typically only done for noise (cold-start rattle), chain stretch, guide wear, or related oil/cam timing faults.

Difficulty Level: Advanced | Estimated Time: 10-16 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine; hot coolant can cause severe burns.
• ⚠️ Disconnect the negative battery terminal to prevent accidental cranking.
• ⚠️ Support the 4Runner with jack stands; never rely on a jack alone.
• ⚠️ The crankshaft pulley bolt is extremely tight; use the correct holding tool to avoid injury.
• ⚠️ Keep bolts and parts organized—timing cover bolts are different lengths.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Wheel chocks
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Drain pan (at least 10-quart)
• Metric socket set 8mm-22mm
• 3/8" drive ratchet
• 1/2" drive breaker bar (24" minimum)
• Torque wrench 10-80 ft-lbs
• Torque wrench 50-250 ft-lbs
• Metric combination wrench set 8mm-19mm
• Torx bit set
• Screwdriver set (Phillips and flathead)
• Pliers set
• Trim clip removal tool
• Serpentine belt tool (long-handled)
• Crankshaft pulley holding tool (specialty)
• Harmonic balancer puller kit (specialty)
• Plastic gasket scraper
• Razor scraper
• Brake cleaner spray
• RTV/FIPG sealant applicator
• Shop rags
• Paint marker

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain set (chain + guides + tensioner) - Qty: 1
• Timing cover sealant (Toyota FIPG/RTV equivalent) - Qty: 1
• Crankshaft front oil seal - Qty: 1
• Engine coolant (Toyota Super Long Life coolant equivalent) - Qty: 2-3 gallons (mixed)
• Engine oil (0W-20 full synthetic) - Qty: 7 quarts
• Oil filter - Qty: 1
• Accessory drive belt - Qty: 1
• Water pump gasket or O-ring (if water pump is removed) - Qty: 1
• Thermostat gasket (recommended while coolant is drained) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Disconnect the negative battery terminal using a 10mm socket.
• Remove the front skid plate(s) with a 12mm socket and a 14mm socket as equipped.
• Plan your organization: poke bolts through labeled cardboard (example: “timing cover top”, “timing cover bottom”).
• Pro tip: Take photos before every removal.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Drain coolant and remove basic access parts

• Place a drain pan (at least 10-quart) under the radiator drain.
• Open the radiator cap, then open the radiator drain using a pliers set if needed.
• Remove the upper engine cover (if equipped) using a 10mm socket.
• Remove the intake duct/air snorkel clamps with a flathead screwdriver.

Step 2: Remove fan shroud and cooling fan assembly

• Remove the fan shroud fasteners using a 10mm socket.
• Remove the fan clutch nuts using a 12mm wrench, then lift the fan and shroud out together.
• Pro tip: Don’t pry the radiator fins.

Step 3: Remove the serpentine belt

• Rotate the belt tensioner with a serpentine belt tool (long-handled) and slip the belt off.
• Set the belt aside (replace it if it’s cracked or glazed).

Step 4: Remove front accessories as needed for timing cover access

• Unbolt accessory brackets/pulleys that block the timing cover using a metric socket set 8mm-22mm and ratchet.
• If moving the A/C compressor or power steering pump aside, support it and do not let it hang by hoses.
• Use a trim clip removal tool for any harness clips on the timing cover.

Step 5: Set cylinder #1 to TDC on compression

• “TDC” means Top Dead Center—piston at the top of its travel.
• Rotate the crankshaft clockwise using a 19mm socket and a 1/2" drive breaker bar.
• Line up the crank timing mark to the “0” mark on the timing scale.
• Use a paint marker to mark chain/sprocket positions before disassembly.

Step 6: Remove the crankshaft pulley (harmonic balancer)

• Install the crankshaft pulley holding tool (specialty) to keep the pulley from turning.
• Loosen and remove the crank bolt using a 22mm socket and a 1/2" drive breaker bar (24" minimum).
• Use the harmonic balancer puller kit (specialty) to pull the pulley off straight.
• Pro tip: Never pry against the timing cover.

Step 7: Remove the timing cover

• Remove all timing cover bolts with a metric socket set 8mm-14mm.
• Carefully break the seal using a plastic gasket scraper; avoid gouging aluminum surfaces.
• Remove the timing cover and set it on clean cardboard.

Step 8: Remove timing chain tensioner, guides, and chain

• Remove the chain tensioner bolts using a 10mm socket, then remove the tensioner.
• Remove chain guides using a 10mm socket.
• Slip the chain off the sprockets.
• If removing cam sprockets is required, use a torque wrench 50-250 ft-lbs for reassembly and mark orientation before removal.

Step 9: Install the new chain, guides, and tensioner

• Confirm the new chain has colored links (timing links) and align them to the timing marks on the sprockets.
• Install new guides using a 10mm socket and torque wrench 10-80 ft-lbs: Torque to 10 Nm (89 in-lbs) unless your kit specifies otherwise.
• Install the new tensioner using a 10mm socket: Torque to 10 Nm (89 in-lbs).
• Release the tensioner pin only after the chain is fully seated and marks are confirmed.

Step 10: Replace the crankshaft front seal

• Remove the old seal carefully using a flathead screwdriver (work slowly to avoid scratching the bore).
• Install the new seal squarely using a suitable driver from the harmonic balancer puller kit (specialty) or a flat installer.

Step 11: Reinstall the timing cover with FIPG/RTV sealant

• Clean all mating surfaces using a razor scraper, brake cleaner spray, and shop rags.
• Apply an even bead of timing cover sealant (Toyota FIPG/RTV equivalent) using an RTV/FIPG sealant applicator.
• Install the timing cover and hand-start all bolts.
• Tighten timing cover bolts evenly using a torque wrench 10-80 ft-lbs: Torque to 9 Nm (80 in-lbs) for small cover bolts.

Step 12: Reinstall crank pulley and torque the crank bolt

• Install the crank pulley fully seated.
• Hold the pulley with the crankshaft pulley holding tool (specialty).
• Tighten the crankshaft bolt using a 22mm socket and torque wrench 50-250 ft-lbs: Torque to 294 Nm (217 ft-lbs).

Step 13: Reinstall accessories, belt, fan, and shroud

• Reinstall brackets/pulleys using a metric socket set 8mm-22mm and torque fasteners to spec if removed.
• Install the serpentine belt using the serpentine belt tool (long-handled) and verify correct routing.
• Reinstall the fan and shroud using a 12mm wrench and 10mm socket.

Step 14: Refill coolant and change oil

• Refill with engine coolant (Toyota Super Long Life coolant equivalent).
• Change oil and filter using the correct tools from your metric socket set 8mm-22mm and a drain pan.
• Reconnect the battery negative terminal using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle; confirm oil pressure light goes out quickly.
• Check for coolant leaks around the timing cover area and radiator hoses.
• Let the engine reach operating temperature, then top off coolant as needed.
• Listen for abnormal chain noise (rattle/knock). If present, shut down and re-check timing alignment.
• Road test 10-15 minutes, then re-check coolant level after cool-down.

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💰 DIY vs Shop Cost

Shop Cost: $1,800-$3,500 (parts + labor)

DIY Cost: $350-$900 (parts only)

You Save: $1,450-$2,600 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 10-16 hours.

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🎯 Ready to get started?

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