Symptoms
Due by mileage or age, no records, a weeping water pump. A failed belt can do severe engine damage, per LC Engineering.
The fix, step by step
- Drain coolant, remove the fan, shroud and drive belts, then the crank pulley and timing covers.
- Set the engine to TDC and mark the belt and pulleys.
- Replace the belt, tensioner pulley, idler pulley and hydraulic belt adjuster, and the water pump — which is driven by the belt — then rotate the crank two full turns to confirm the marks before reassembly.
Tools & part numbers
- Crank pulley holder and puller
- torque wrench
- LCE 2UZ-FE timing belt kit
- hydraulic timing belt adjuster
- Aisin water pump
Where to buy the parts
Timing belt kit (belt, tensioner & idler pulleys) — 2UZ-FELC Engineering ↗Amazon ↗
Hydraulic timing belt adjuster — 2UZ-FELC Engineering ↗Amazon ↗
Water pumps — 2005 4Runner catalogRockAuto ↗
Hunting a used or discontinued part? Search eBay Motors for Toyota 4Runner 4th Gen parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.