Lexus RX300 1MZ-FE 03-06 Water Pump

Water Pump – OEM-Spec Replacement

Maintain correct coolant flow and stable operating temperature with an OEM-spec water pump. This unit is matched to your vehicle’s application (mechanical or electric, depending on model) for reliable cooling and long-term durability.

Why replace the water pump

• Restores correct coolant circulation to prevent overheating
• Protects head gasket, radiator, thermostat and hoses from heat stress
• OEM-aligned design for proper fitment and seal integrity
• Supports efficient heater performance and stable cabin temperatures

Pump type overview

Common symptoms of a failing pump

• Coolant leaks or a sweet smell near the pump area
• Grinding or whining noises increasing with engine speed (mechanical)
• Temperature gauge spikes, overheating warnings, or coolant light
• Heater blowing cold at idle, then warm at higher RPM (low coolant flow)

What’s included

• Water pump assembly matched to the listed vehicle application
• Gasket or O-ring where applicable

Images are for illustration. Always confirm by OE/part number or VIN where possible.

Installation best practice

• Inspect and replace the drive belt and tensioner (mechanical pumps) if worn
• Use fresh, correct-spec coolant and bleed the system properly
• Clean gasket surfaces thoroughly and torque bolts to manufacturer specs
• For electric pumps, check wiring and perform the manufacturer bleed procedure

Coolant type and warranty importance

Using the correct coolant is critical for pump performance and long-term engine protection. Mechanical and electric water pumps rely on clean, corrosion-inhibited coolant to lubricate seals and prevent cavitation damage. Mixing coolants or using plain tap water can lead to premature bearing failure, seal leaks, and corrosion inside the block and radiator.

Always use manufacturer-approved synthetic coolant such as G12 or G12++ (depending on the vehicle specification) and mix only with deionised or distilled water. Using incorrect or contaminated coolant can reduce pump life and may void your warranty.

Browse our full range of OEM-spec coolants here: https://onlinecarparts.co.za/7435-coolant

Why buy from Online Car Parts

• OEM-spec components selected for South African conditions
• Fitment help via WhatsApp: 069 777 2 777 | Call: 010 970 6009
• Secure checkout and fast nationwide delivery
• Trusted South African supplier since 2011

Warranty & important notes

• 12-month warranty against manufacturing defects
• Failure to flush and bleed the cooling system correctly can cause repeat overheating
• Using incorrect coolant or plain water can cause corrosion and void warranty

FAQs

Is this a mechanical or electric water pump?
It matches the application listed for your vehicle. Some models use a belt-driven mechanical pump, others an ECU-controlled electric pump.

Do I need extra parts?
New coolant is always recommended. For mechanical pumps, inspect the belt/tensioner. For electric pumps, follow the correct bleed procedure.

How do I confirm fitment?
Match by VIN or OE number. If unsure, contact us before ordering.