Quick answer: Timing Belt and Water Pump Replacement on a 2004–2006 Lexus RX is rated Advanced and takes about 4-6 hours. You'll need 10 tools for this job, and parts cost about $330. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name |
Part Number |
Price |
Buy |
| Timing Belt Kit |
TKT-021 |
$150.00 |
|
| Water Pump |
— |
$100.00 |
|
| Timing Belt Tensioner |
— |
$50.00 |
|
| Idler Pulley |
— |
$30.00 |
|
| Water pump gasket or sealant |
— |
— |
|
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Step-by-Step Instructions
Follow these steps carefully
1
Disconnect the battery and drain the cooling system
Disconnect the negative battery cable. Drain the coolant into a pan. On the Lexus RX330, timing-belt service usually includes the water pump — plan to replace the pump, tensioner, and idlers as a kit. Wear gloves and eye protection.
🔧 Mechanic's note — Ray Delgado
I've learned: negative cable off first, on last. One wrench slip against the body with the positive connected and you're buying fuses.
2
Set engine to TDC and lock the timing
Remove belts, pulleys, and timing covers as required for access. Rotate the engine by hand to Top Dead Center on cylinder 1 and install the factory cam/crank locking pins or marks specified for this engine. Never rely on guesswork for timing marks.
3
Relieve tension and remove the old belt and pump
Release the timing-belt tensioner, slide the belt off the sprockets, and remove the water pump with its bolts (note bolt lengths). Clean all gasket surfaces carefully — do not gouge aluminum mating faces.
🔧 Mechanic's note — Ray Delgado
I always run your finger across the sealing surface when you think it's clean. If you feel ridges, it's not clean yet.
4
Install the new water pump and timing components
Install the new water pump with the specified gasket or sealant and torque bolts evenly. Fit the new tensioner and idlers. Route the new timing belt per the diagram with correct tooth engagement on crank and cam sprockets.
5
Set tension, verify marks, and reassemble
Apply tensioner preload per the procedure, then double-check that all timing marks/locks still align. Rotate the engine by hand at least two full crank revolutions and reconfirm marks before refitting covers, pulleys, and accessory belts.
6
Refill coolant, start, and verify
Reconnect the battery, refill and bleed the cooling system, then start the engine and listen for unusual timing noise. Confirm stable temperature, no coolant leaks at the pump, and normal oil pressure. Recheck coolant level after cooldown.
🔧 Mechanic's note — Ray Delgado
In my experience, if the pedal feels spongy or the heater blows cold after the job, that's trapped air talking. Bleed it again before you blame parts.
All Done!
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
- • Failing to properly align timing marks, leading to engine misfire or damage.
- • Not replacing the water pump during timing belt replacement, risking future failure.
- • Over-tightening bolts, potentially causing thread damage or component breakage.
