🔧 Colorado - Timing Drive Inspection

Your Colorado does not use a timing belt. The 2.5L inline-4 engine uses an internal timing chain, which is designed to last much longer than a belt and is lubricated by engine oil.

Because this is a timing chain system, there is no normal “timing belt replacement” service. Timing chain replacement is only done if there is a confirmed fault such as chain stretch, guide failure, tensioner failure, engine rattle, or timing-related trouble codes.

Difficulty Level: Advanced | Estimated Time: 8-12 hours

---

⚠️ Safety & Precautions

• ⚠️ This repair can cause serious engine damage if camshaft or crankshaft timing is set incorrectly.
• ⚠️ Disconnect the negative battery cable before working near the starter, alternator, or front engine harness.
• ⚠️ Support your Colorado safely if lifting it. Never rely on a jack alone.
• ⚠️ Let the engine cool completely before removing coolant hoses or front engine covers.
• ⚠️ The timing chain is inside the engine. Dirt or dropped hardware can damage internal parts.

---

🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 13mm socket
• 15mm socket
• 18mm socket
• 24mm socket
• 3/8-inch drive ratchet
• 1/2-inch drive breaker bar
• 1/2-inch drive torque wrench
• 3/8-inch drive torque wrench
• Serpentine belt tool
• Harmonic balancer puller (specialty)
• Crankshaft holding tool (specialty)
• Camshaft alignment tool (specialty)
• Crankshaft alignment pin (specialty)
• Plastic trim clip remover
• Flat-blade screwdriver
• Pick tool set
• Gasket scraper
• Drain pan 10-quart minimum
• Floor jack rated 3-ton minimum
• Jack stands rated 3-ton minimum
• Wheel chocks
• Safety glasses
• Nitrile gloves

---

🔩 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
• Crankshaft front seal - Qty: 1
• Front timing cover gasket set - Qty: 1
• Valve cover gasket - Qty: 1
• Crankshaft pulley bolt - Qty: 1
• Engine oil 5W-30 full synthetic - Qty: 5 quarts
• Oil filter - Qty: 1
• Engine coolant Dex-Cool compatible - Qty: As needed
• RTV engine sealant - Qty: 1 tube

---

📋 Before You Begin

• 🅿️ Park your Colorado on level ground and set the parking brake.
• 🧊 Let the engine cool completely before starting.
• 🔋 Use a 10mm socket to disconnect the negative battery cable.
• 🛞 Place wheel chocks behind the rear wheels before lifting the front.
• 📌 A timing chain keeps the crankshaft and camshafts synchronized so the valves and pistons move at the correct time.
• 📌 A harmonic balancer puller is a tool that removes the front crankshaft pulley without damaging it.
• 📌 Camshaft and crankshaft alignment tools lock the engine in the correct timed position during repair.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Verify This Repair Is Needed

• Use a scan tool if available to check for timing-related codes such as camshaft/crankshaft correlation faults.
• Listen for a cold-start rattle from the front of the engine using safety glasses and gloves.
• If there are no timing faults, no chain noise, and no drivability symptoms, replacement is usually not needed.
• Do not replace a good chain.

Step 2: Raise and Secure the Front

• Use a floor jack rated 3-ton minimum to lift the front of your Colorado at the proper front lift point.
• Place jack stands rated 3-ton minimum under the frame support points.
• Lower the truck gently onto the jack stands.
• Use wheel chocks at the rear wheels.

Step 3: Remove the Engine Appearance Cover and Intake Duct

• Use a 10mm socket to remove any fasteners holding the engine cover if equipped.
• Use a flat-blade screwdriver to loosen the intake duct clamps.
• Remove the duct and set it aside.

Step 4: Drain Fluids

• Place a 10-quart drain pan under the radiator drain area.
• Use gloves and open the coolant drain carefully if coolant hoses or the front cover area must be removed.
• Use a 15mm socket to remove the oil drain plug if you are changing oil during the repair.
• Reinstall the oil drain plug and torque to 25 Nm (18 ft-lbs).

Step 5: Remove the Serpentine Belt

• Use a serpentine belt tool on the belt tensioner.
• Rotate the tensioner slowly to release belt tension.
• Slide the belt off the pulleys and remove it.
• Take a belt routing photo first.

Step 6: Remove Front Accessories as Needed

• Use 10mm, 13mm, and 15mm sockets to remove brackets and accessories blocking the front timing cover.
• Move wiring harnesses aside gently using a plastic trim clip remover.
• Do not pull on wires. Release clips first with a pick tool if needed.

Step 7: Remove the Valve Cover

• Use a 10mm socket to remove ignition coil fasteners and valve cover bolts.
• Use a plastic trim clip remover to release harness clips from the cover.
• Lift the valve cover straight up.
• Remove the old valve cover gasket by hand or with a pick tool.

Step 8: Set Cylinder 1 at Top Dead Center

• Use a 24mm socket and 1/2-inch breaker bar on the crankshaft pulley bolt.
• Rotate the engine clockwise only until cylinder 1 is at top dead center.
• Top dead center means piston 1 is at the very top of its travel on the compression stroke.
• Install the crankshaft alignment pin and camshaft alignment tool according to the tool markings.
• Timing marks must line up exactly.

Step 9: Remove the Crankshaft Pulley

• Use a crankshaft holding tool to keep the crankshaft from turning.
• Use a 24mm socket and 1/2-inch breaker bar to loosen the crankshaft pulley bolt.
• Remove the bolt and discard it if the replacement kit includes a new torque-to-yield bolt.
• Use a harmonic balancer puller to remove the crankshaft pulley.

Step 10: Remove the Front Timing Cover

• Use 10mm and 13mm sockets to remove all front timing cover bolts.
• Use a pick tool to check for hidden bolts around brackets and lower cover areas.
• Gently separate the cover using a gasket scraper at safe pry points only.
• Do not gouge the aluminum sealing surfaces.

Step 11: Remove the Timing Chain Tensioner and Guides

• Use a 10mm socket to remove the timing chain tensioner bolts.
• Use a 10mm or 13mm socket to remove the timing chain guide bolts.
• Remove the guides and tensioner.
• Keep the camshaft alignment tool installed so timing does not move.

Step 12: Remove the Timing Chain

• Use your hands to slide the timing chain off the sprockets.
• If the chain is tight, recheck that the tensioner is fully removed.
• Do not rotate the crankshaft or camshafts after the chain is removed.

Step 13: Install the New Timing Chain

• Use the colored chain links to match the timing marks on the crankshaft and camshaft sprockets.
• Install the new chain by hand over the sprockets.
• Use the camshaft alignment tool and crankshaft alignment pin to confirm everything remains locked in position.
• One tooth off is too much.

Step 14: Install New Guides and Tensioner

• Use a 10mm socket to install the new timing chain guides.
• Use a torque wrench and torque guide bolts to 10 Nm (89 in-lbs) unless the kit instructions specify otherwise.
• Use a 10mm socket to install the new timing chain tensioner.
• Use a torque wrench and torque tensioner bolts to 10 Nm (89 in-lbs).
• Release the tensioner pin only after the chain and guides are correctly installed.

Step 15: Rotate the Engine by Hand

• Remove the camshaft alignment tool and crankshaft alignment pin.
• Use a 24mm socket and breaker bar to rotate the crankshaft clockwise two full turns.
• Reinstall the alignment tools to verify timing still lines up.
• If the tools do not fit, stop and correct the timing before reassembly.

Step 16: Clean and Reseal the Front Cover

• Use a gasket scraper to remove old sealant from the cover and engine block.
• Wipe sealing surfaces clean with a lint-free rag.
• Apply RTV engine sealant to the specified front cover sealing areas.
• Install a new crankshaft front seal into the timing cover if not pre-installed.

Step 17: Reinstall the Front Timing Cover

• Place the timing cover straight onto the engine without smearing the sealant.
• Use a 10mm socket to start all cover bolts by hand.
• Use a torque wrench and torque small timing cover bolts to 10 Nm (89 in-lbs).
• Use a torque wrench and torque larger timing cover bolts to 25 Nm (18 ft-lbs) where applicable.

Step 18: Reinstall the Crankshaft Pulley

• Use your hands to align the crankshaft pulley on the crankshaft nose.
• Use a 24mm socket to install the new crankshaft pulley bolt.
• Use the crankshaft holding tool and torque wrench to tighten the bolt.
• Torque to 150 Nm (111 ft-lbs), then tighten an additional 100 degrees if using a torque-to-yield replacement bolt.

Step 19: Reinstall the Valve Cover

• Install the new valve cover gasket by hand into the valve cover groove.
• Use a 10mm socket to install the valve cover bolts.
• Use a torque wrench and torque valve cover bolts to 10 Nm (89 in-lbs).
• Reconnect ignition coils and harness clips by hand.

Step 20: Reinstall Accessories, Belt, and Intake

• Use 10mm, 13mm, and 15mm sockets to reinstall removed brackets and accessories.
• Use the serpentine belt tool to rotate the belt tensioner.
• Route the belt over the pulleys exactly as photographed.
• Use a flat-blade screwdriver to tighten intake duct clamps.

Step 21: Refill Oil and Coolant

• Install a new oil filter by hand, then tighten until snug according to the filter instructions.
• Add 5W-30 full synthetic engine oil.
• Refill with Dex-Cool compatible coolant if coolant was drained.
• Reconnect the negative battery cable using a 10mm socket.

---

✅ After Repair

• ✅ Before starting, crank the engine briefly and listen for abnormal clanking or binding.
• ✅ Start the engine and let it idle. It may rattle for a second while oil pressure fills the tensioner.
• ✅ Check carefully for oil and coolant leaks around the front cover, valve cover, and crankshaft seal.
• ✅ Let the engine reach operating temperature, then shut it off and recheck fluid levels after cooling.
• ✅ If a scan tool is available, clear any stored timing-related codes and recheck for pending codes after a road test.
• ✅ Road test gently for 10-15 minutes, then inspect again for leaks.

---

💰 DIY vs Shop Cost

Shop Cost: $1,400-$2,400 (parts + labor)

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

You Save: $1,000-$1,750 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 8-12 hours.

---

🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.