🔧 Altima - Timing Chain Replacement

Your Altima’s 2.5L engine uses a timing chain, not a timing belt. A chain usually lasts a long time, but it may need replacement if it’s noisy at startup, has timing-related trouble codes, or you find excessive slack.

Assumption: Stock 2.5L engine; replacing the primary timing chain set and resealing the front cover.

Difficulty Level: Advanced | Estimated Time: 6-10 hours

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⚠️ Safety & Precautions

• 🧯 Work on a cool engine; hot coolant/oil can burn you.
• 🧰 Support the engine before removing the right engine mount (engine can drop).
• 🛑 Use jack stands; never work under a car supported only by a jack.
• 🔋 Disconnect the negative battery terminal to prevent accidental cranking.
• ⚠️ Keep hands clear when rotating the crankshaft; pinch hazard.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Drain pan (at least 10-quart)
• Metric socket set 8mm-19mm
• Deep socket 19mm
• Ratchet 3/8" drive
• Breaker bar 1/2" drive
• Torque wrench 10-250 Nm
• Wrench set 10mm-19mm
• Screwdriver set
• Pliers set
• Trim clip removal tool
• Serpentine belt tool 14mm
• Crank pulley holder tool (specialty)
• Harmonic balancer puller (specialty)
• Plastic razor scraper
• Gasket scraper
• Brake cleaner spray
• RTV silicone applicator gun
• Fender cover
• Flashlight
• Paint marker

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain kit (primary chain, tensioner, guides) - Qty: 1
• Front timing cover sealant (RTV, OEM-equivalent) - Qty: 1
• Crankshaft front oil seal - Qty: 1
• Engine oil (0W-20 full synthetic) - Qty: 5 quarts
• Oil filter - Qty: 1
• Engine coolant (Nissan-compatible blue long-life) - Qty: 1-2 gallons
• Accessory drive belt - Qty: 1
• Front cover bolt/gasket kit (if offered) - 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 cable using a 10mm socket.
• 🧊 Place a drain pan under the radiator and plan to drain coolant before removing the front cover.
• 🧰 Lay bolts out in order; front cover bolts are different lengths.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and access the passenger-side front of the engine

• Loosen the front passenger wheel lug nuts with a 19mm socket.
• Lift the front with a floor jack (rated 3-ton minimum) and support with jack stands (rated 3-ton minimum).
• Remove the wheel using a 19mm socket.
• Remove the splash shield/inner liner clips using a trim clip removal tool and screwdriver set.

Step 2: Drain coolant

• Place a drain pan (at least 10-quart) under the radiator.
• Open the drain cock carefully using a screwdriver set (if slotted) and drain coolant.
• Cap/close the drain when finished to avoid drips.

Step 3: Remove the accessory drive belt

• Relieve belt tension using a serpentine belt tool 14mm on the tensioner.
• Slide the belt off the pulleys and remove it.
• Tip: Draw a quick belt routing sketch.

Step 4: Support the engine and remove the right engine mount

• Place a floor jack (rated 3-ton minimum) under the oil pan with a block of wood (spreads load).
• Gently raise the jack until it just supports the engine.
• Remove the right engine mount fasteners using a metric socket set 8mm-19mm and wrench set 10mm-19mm.
• Set the mount aside and keep bolts grouped by location.

Step 5: Remove the crank pulley (harmonic balancer)

• Install the crank pulley holder tool (specialty) to keep the pulley from turning (this tool locks the pulley while you loosen/tighten the bolt).
• Break the crank bolt loose using a breaker bar 1/2" drive and deep socket 19mm.
• Remove the pulley using a harmonic balancer puller (specialty).
• During reassembly: crank bolt Torque to 220 Nm (162 ft-lbs).

Step 6: Remove front cover components in the way

• Remove any brackets and the upper/lower front cover fasteners using a metric socket set 8mm-19mm.
• Disconnect hoses/clips that attach to the front cover using pliers set and a screwdriver set.
• Wipe oil/coolant with shop towels (use brake cleaner spray for final cleaning later).

Step 7: Set cylinder #1 to Top Dead Center (TDC) on compression

• Rotate the crankshaft clockwise using a deep socket 19mm and breaker bar 1/2" drive until timing marks align.
• Use a flashlight and paint marker to highlight the marks before disassembly.
• Tip: Only rotate clockwise to avoid slack errors.

Step 8: Remove the front timing cover

• Remove all front cover bolts using a metric socket set 8mm-19mm.
• Carefully separate the cover from the engine using a plastic razor scraper (avoid gouging aluminum).
• Lift the cover off and set it on a clean surface.
• During reassembly: front cover bolts typically Torque to 12 Nm (9 ft-lbs) unless otherwise marked.

Step 9: Remove the timing chain tensioner and guides

• Remove the tensioner fasteners using a metric socket set 8mm-19mm and remove the tensioner.
• Remove timing chain guide bolts using a metric socket set 8mm-19mm and remove the guides.
• Keep hardware with each part so nothing gets mixed up.

Step 10: Remove and install the timing chain

• Slip the chain off the sprockets carefully (keep the crank and cams from moving).
• Install the new chain, aligning the colored links with the sprocket timing marks (use a flashlight).
• Install new guides using a metric socket set 8mm-19mm and torque wrench 10-250 Nm.
• Guide bolts: Torque to 12 Nm (9 ft-lbs).

Step 11: Install the new tensioner and verify timing

• Install the new tensioner using a metric socket set 8mm-19mm.
• Tensioner bolts: Torque to 12 Nm (9 ft-lbs).
• Release the tensioner pin (if equipped) so it takes up chain slack.
• Rotate the engine by hand 2 full turns clockwise using a deep socket 19mm and breaker bar 1/2" drive, then re-check timing mark alignment.
• Tip: If marks don’t line up, stop and re-time.

Step 12: Replace the crankshaft front seal

• Remove the old seal carefully using pliers set (gentle prying only).
• Press in the new seal evenly (flush and square). Use a suitable flat driver from your metric socket set 8mm-19mm as a press tool.

Step 13: Clean and reseal the front cover

• Clean all mating surfaces using a gasket scraper, plastic razor scraper, and brake cleaner spray.
• Apply a continuous bead of front timing cover sealant (RTV, OEM-equivalent) using an RTV silicone applicator gun.
• Install the front cover and hand-start all bolts using a ratchet 3/8" drive.
• Tighten bolts evenly with a torque wrench 10-250 Nm: Torque to 12 Nm (9 ft-lbs).
• Tip: Too much RTV can cause leaks.

Step 14: Reinstall the crank pulley

• Reinstall the pulley by hand first, then install the crank bolt using a deep socket 19mm.
• Hold the pulley with the crank pulley holder tool (specialty).
• Tighten with a torque wrench 10-250 Nm: Torque to 220 Nm (162 ft-lbs).

Step 15: Reinstall engine mount, belt, and shields

• Reinstall the right engine mount using a metric socket set 8mm-19mm and wrench set 10mm-19mm.
• Tighten mount fasteners with a torque wrench 10-250 Nm (typical mount fasteners: Torque to 55 Nm (41 ft-lbs) if no spec label is present).
• Install the new belt using a serpentine belt tool 14mm.
• Reinstall splash shields and clips using a trim clip removal tool and screwdriver set.
• Reinstall wheel using a 19mm socket. Lug nuts: Torque to 113 Nm (83 ft-lbs).

Step 16: Refill fluids

• Refill cooling system with engine coolant (Nissan-compatible blue long-life).
• Change oil and filter (front cover work can contaminate oil). Use a drain pan (at least 10-quart), metric socket set 8mm-19mm, and ratchet 3/8" drive.

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✅ After Repair

• 🔍 Reconnect the battery using a 10mm socket.
• 🧪 Start the engine and let it idle. Listen for abnormal rattles.
• 🛠️ Check for oil leaks around the front cover and crank seal.
• 🌡️ Bring the engine to operating temperature and verify the heater blows hot (helps confirm coolant flow).
• 💧 Recheck coolant level after the first full heat-soak and top off as needed.

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💰 DIY vs Shop Cost

Shop Cost: $1,200-$2,200 (parts + labor)

DIY Cost: $250-$650 (parts only)

You Save: $550-$1,950 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 6-10 hours.

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🎯 Ready to get started?

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