The 3.4L V6 (5VZ-FE) in 1st-gen Tacomas needs its timing belt replaced every 90,000 miles, and you do the water pump at the same time because it is driven by the belt and you are already in there. Good news: the 5VZ-FE is a non-interference engine, so a snapped belt strands you but does not bend valves — it is not the catastrophe it is on interference engines. Use a complete Aisin kit (~$230) since Aisin is the OE supplier. A shop charges $600–900; doing it yourself runs $250–700 in parts depending on how much you replace while you are in there. Budget a full day your first time.
This is the defining maintenance job on a 1st-gen Tacoma's 3.4L V6, and the single best thing you can do for one with unknown history. If you bought a 5VZ-FE Tacoma and have no record of the belt, assume it is due and do it. A failed belt won't destroy the engine on this motor, but it will leave you stranded, and the water pump that lives behind the belt is a known wear item — replacing both together is the only sensible plan.
**Non-interference is the relief.** On the 5VZ-FE, the pistons and valves do not occupy the same space at the same time. If the belt breaks, the engine stops and you are stuck, but you replace the belt and drive away — no bent valves, no rebuild. That fact lowers the stakes versus an interference engine, but it is not a reason to skip the interval, because being stranded on a trail or a highway is its own problem.
**Why the water pump goes with it.** The 5VZ-FE water pump is driven by the timing belt and sits behind the same covers. The labor to reach it is 90% of the timing-belt labor. Replacing a $40 belt and leaving a 90K-mile pump in place means tearing it all apart again when the pump leaks. Always do the pump, tensioner, idler, and the front seals (cam and crank) in the same job — that is why kits exist.
**Buy the kit from the OE supplier.** Aisin supplies Toyota's water pumps and timing components. An Aisin complete kit (belt, tensioner, idler pulley, water pump, gaskets, and seals) is the right part at the right price — around $230. Avoid the cheapest no-name kits; a water pump or tensioner that fails early forces the whole job over again.
**Timing marks are the make-or-break.** Set the engine to top dead center on cylinder 1 and confirm every timing mark before the old belt comes off. Mark the belt direction and the cam/crank positions. The 5VZ-FE has clear factory marks — line them up exactly on reassembly. Getting a tooth off causes a rough-running engine and codes; double-check before you button it up.
**Safety — support and cooling.** This job involves draining coolant and working at the front of the engine with the radiator and fan area open. Let the engine cool fully before draining coolant. If you raise the truck, use jack stands rated for the weight — never trust a jack alone while reaching into the engine bay. Refill with Toyota pink SLLC and burp the cooling system afterward.
| Part | Vendor | Est. price |
|---|---|---|
| Aisin timing belt kit (belt, tensioner, idler, water pump, seals) | Aisin | ~$230 |
| OE timing belt only (if doing belt-only) | Toyota/Mitsuboshi | ~$45 |
| Toyota pink SLLC coolant (gal) | Toyota | ~$28 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.