Parts for your 2004 Toyota Highlander-Water pump

2004 Toyota Highlander water pump — what it does and when to replace it

Per factory Toyota service information (TIS) for the 2004 Highlander and widely used parts catalogues from OEM suppliers (Aisin) and timing component manufacturers (Gates), every 2004 Toyota Highlander is fitted with a mechanical engine‑driven water pump. The 2.4‑litre 2AZ‑FE uses an accessory (serpentine) belt‑driven pump, while the 3.3‑litre 3MZ‑FE V6 runs its pump off the timing belt. Those technical sources are the standard references workshops in Australia and New Zealand rely on for fitment and service procedures.

On this model, the water pump’s job is simple but vital: keep coolant circulating through the block, heads, radiator and heater core so the engine holds a steady operating temperature. That protects head gaskets, prevents hot spots, and keeps the cabin heater working on frosty mornings. It’s a hard‑working bit of kit and, over time, seals, bearings and gaskets can wear.

Servicing advice varies slightly by engine. On the 3.3L V6 (3MZ‑FE), the pump sits behind the timing cover and is driven by the timing belt. Best practice is to replace the water pump whenever the timing belt is done — typically around 150,000 km — because the extra parts cost is modest compared with the labour to go back in later. Most workshop guides and Gates’ timing component listings echo this “do it together” approach. On the 2.4L (2AZ‑FE), the pump is external and driven by the accessory belt, so it’s usually replaced on condition: if it leaks, gets noisy, or shows play at the pulley.

Tell‑tale signs it’s time:

• Pink or white crusty residue or a coolant drip near the pump or timing cover
• Growling/whirring from the pump area or wobble at the pulley
• Engine temperature creeping up, or poor heater performance

When fitting a new pump, most technicians prefer an OEM‑quality unit (Aisin is the factory supplier), a fresh gasket/O‑ring, and new coolant. Use Toyota Super Long Life Coolant (pink), mix correctly if using concentrate, and bleed the system properly with the heater on to purge air. On the V6, it’s smart to replace the timing belt, tensioner and idlers in one hit. On the 4‑cyl, inspect the accessory belt and tensioner while the bonnet’s up. After any pump job, check for leaks at the weep hole and fastener areas, top up after a heat‑soak, and recheck coolant level over the next few drives.

Popular questions

Does a 2004 Toyota Highlander have a water pump?
Yes. Technical documentation from Toyota TIS and parts catalogues from Aisin and Gates confirm both engines (2.4L 2AZ‑FE and 3.3L 3MZ‑FE) use a mechanical water pump. The V6 pump is driven by the timing belt, the 4‑cyl pump is driven by the accessory belt.

When should the water pump be replaced?
On the 3.3L V6, replace the pump whenever the timing belt is serviced (around 150,000 km under typical schedules). On the 2.4L 4‑cyl, replace on condition — if there’s leakage, bearing noise, or pulley play — and inspect it at each coolant service.

What coolant should be used after a pump replacement?
Use Toyota Super Long Life Coolant (pink). It’s formulated for Toyota alloy engines and helps protect the pump’s seals and bearings. Refresh at the intervals specified by Toyota and always bleed the system of air after refilling.