🔧 GS350 - Timing Belt Replacement

Your GS350 does not use a timing belt. It uses a timing chain, which normally lasts the life of the engine and isn’t a routine maintenance item like a belt.

If you’re having timing-related issues (rattle on cold start, cam/crank correlation codes, oil leaks at the front cover), the correct repair is a timing chain/front cover service, not a belt replacement.

Difficulty Level: Advanced | Estimated Time: 8-14 hours

Assumption: Stock 2GR-series V6 with factory timing chain.

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine; hot coolant/oil can burn you.
• ⚠️ Disconnect the 12V battery negative terminal before starting.
• ⚠️ Support the car with jack stands; never rely on a floor jack.
• ⚠️ The engine may need to be supported when mounts/brackets are loosened.
• ⚠️ Keep fingers clear when rotating the crankshaft.

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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)
• Metric socket set 8mm-22mm
• Metric wrench set 8mm-22mm
• 1/4" drive ratchet
• 3/8" drive ratchet
• 1/2" drive breaker bar
• Torque wrench 10-200 ft-lbs
• Torque wrench 50-300 ft-lbs
• Extensions set 3"-12"
• Trim clip remover
• Flathead screwdriver
• Pliers set
• Drain pan 10-quart
• Funnel
• Gasket scraper
• Plastic razor blade scraper
• Harmonic balancer puller (specialty)
• Crank pulley holding tool (specialty)
• Engine support bar (specialty)
• OBD2 scan tool

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain kit - Qty: 1
• Timing chain tensioner - Qty: 1
• Timing chain guides - Qty: 1 set
• Front crankshaft seal - Qty: 1
• Front timing cover sealant (FIPG RTV) - Qty: 1
• Engine oil (SAE 0W-20 full synthetic) - Qty: 7 quarts
• Oil filter - Qty: 1
• Engine coolant (Toyota/Lexus Super Long Life) - Qty: 2-3 gallons
• Serpentine belt - Qty: 1
• Front cover O-rings/seals (as applicable) - Qty: 1 set

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Disconnect the battery using a 10mm socket at the negative terminal.
• Raise the front and support it on jack stands at the proper lift points.
• Plan for fluid handling: you’ll drain coolant and oil into a 10-quart drain pan.
• Know these terms: the harmonic balancer is the crank pulley; FIPG is RTV sealant used instead of a paper gasket.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Disconnect battery and prep the workspace

• Use a 10mm socket to remove the negative battery terminal and isolate it.
• Use wheel chocks, a floor jack, and jack stands to secure the car safely.

Step 2: Remove lower covers and drain fluids

• Remove the engine under cover using a trim clip remover and 10mm socket.
• Drain engine oil into a drain pan using the correct oil drain plug socket from your metric socket set.
• Drain coolant into a drain pan by opening the radiator drain cock with a flathead screwdriver.

Step 3: Remove intake ducting and front accessory drive items

• Remove the intake duct/clamps using a flathead screwdriver and 10mm socket.
• Relieve belt tension and remove the serpentine belt using the correct size from your metric socket set and a breaker bar.

Step 4: Support the engine (if required for access)

• Install an engine support bar (specialty) per its instructions to hold the engine from above.
• Do not lift; just support the weight.

Step 5: Remove the crank pulley (harmonic balancer)

• Hold the crank pulley with a crank pulley holding tool (specialty).
• Loosen the crank bolt using a 1/2" breaker bar and the correct socket from your metric socket set.
• Remove the pulley using a harmonic balancer puller (specialty).
• Torque to 250 Nm (184 ft-lbs) for the crank bolt on reassembly.

Step 6: Remove components blocking the timing cover

• Remove any brackets, accessory mounting hardware, and front cover-attached items using a metric socket set 8mm-22mm and extensions.
• Keep bolts organized by location/length; cover bolts are often different lengths.

Step 7: Remove the front timing cover

• Remove the timing cover bolts using a metric socket set.
• Carefully break the RTV seal using a plastic razor blade scraper and gasket scraper.
• Do not pry on sealing surfaces.

Step 8: Set cylinder #1 to TDC and verify timing marks

• Rotate the engine clockwise using a socket on the crank with a 1/2" drive ratchet.
• Align the chain and sprocket timing marks exactly before removing the chain.
• If marks don’t line up, rotate again—never force anything.

Step 9: Remove tensioner, guides, and timing chain

• Remove the timing chain tensioner bolts using a metric socket set.
• Remove the chain guides using a metric socket set.
• Remove the timing chain once tension is released.

Step 10: Install new chain, guides, and tensioner

• Install the new chain aligned to the timing marks exactly as removed.
• Install new guides using a torque wrench and the correct socket from your metric socket set.
• Install and release the new tensioner per kit instructions.
• Hand-rotate the crankshaft 2 full turns with a ratchet and re-check timing marks.

Step 11: Reseal and reinstall the timing cover

• Clean all old RTV from mating surfaces using a plastic razor blade scraper and gasket scraper.
• Apply a continuous bead of front timing cover sealant (FIPG RTV) per the sealant instructions.
• Install the cover bolts using a torque wrench and metric socket set.
  Torque to 9 Nm (80 in-lbs) for typical small cover bolts.
• Let RTV skin before adding fluids.

Step 12: Reinstall crank pulley and accessories

• Install a new front crankshaft seal if removed using hand pressure and a suitable socket from your metric socket set.
• Reinstall the crank pulley and crank bolt using a crank pulley holding tool (specialty) and torque wrench.
  Torque to 250 Nm (184 ft-lbs).
• Reinstall brackets/accessories and the serpentine belt using a metric socket set.

Step 13: Refill fluids and reconnect battery

• Install a new oil filter by hand and tighten per filter instructions.
• Refill engine oil using a funnel with SAE 0W-20.
• Refill coolant using a funnel with Toyota/Lexus SLLC and bleed air as needed.
• Reconnect the battery negative terminal using a 10mm socket.

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✅ After Repair

• Start the engine and listen for abnormal rattles; shut down immediately if you hear loud chain noise.
• Check for oil and coolant leaks at the front cover area.
• Use an OBD2 scan tool to check for codes and confirm none return after a short test drive.
• Recheck coolant level after the first full heat cycle and top off if needed.

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💰 DIY vs Shop Cost

Shop Cost: $2,500-$4,500 (parts + labor)

DIY Cost: $450-$1,100 (parts only)

You Save: $2,000-$3,400 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 8-14 hours.

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🎯 Ready to get started?

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