Parts for your 2003 Toyota Highlander-Water pump

2003 Toyota Highlander (Kluger) water pump — what it does and when to service it

Referencing technical sources — Toyota factory repair information, the Toyota Electronic Parts Catalogue, and OEM application catalogues from Aisin and Gates — the 2003 Toyota Highlander (also sold as Kluger in AU/NZ) is absolutely fitted with a water pump. Both engines offered that year use a mechanical pump: the 2.4L 2AZ-FE four-cylinder drives the pump via the accessory belt, while the 3.0L 1MZ-FE V6 drives it off the timing belt.

The water pump’s job is simple but critical: it keeps coolant moving through the engine, radiator and heater core so temperatures stay in the sweet spot. Inside is an impeller, spinning on a shaft supported by a bearing and sealed to keep coolant in. When that bearing or seal wears, leaks or noise start, and if ignored, overheating can quickly follow — not something anyone wants under the bonnet on a summer arvo.

On a V6 Highlander/Kluger, the pump sits behind the timing covers and is driven by the timing belt, so it’s smart practice to replace the water pump when doing the timing belt service (typically around 150,000 km, or 90,000–105,000 miles, depending on the local schedule). On the 2.4L four-cylinder, the pump is driven by the accessory belt