Parts for your 2007 Toyota Highlander-Radiator cap

2007 Toyota Highlander (Kluger) Radiator Cap — What It Does and How to Service It

Based on technical references, the 2007 Toyota Highlander (also known as Kluger in Australia and New Zealand) is fitted with a radiator cap for the engine cooling system. Toyota’s factory Repair Manual for this model year includes a “Radiator Cap: Inspect” and pressure-testing procedure in the Cooling System section, the Owner’s Manual warns against removing the radiator cap when hot, and the Toyota Electronic Parts Catalogue lists a pressure cap for the 2AZ-FE (2.4L) and 3MZ-FE (3.3L, including Hybrid) engine cooling systems. Depending on engine and market, the cap may sit on the radiator neck or on a remote filler neck near the upper hose, but it’s absolutely part of the system.

On this Highlander, the radiator cap is a small but critical pressure valve. It seals the cooling system so the coolant can run at a higher pressure, which lifts the boiling point and helps prevent overheating on hot Aussie and Kiwi days or under heavy loads. When pressure builds past the cap’s rating, it allows a controlled bleed of coolant to the overflow bottle. As the engine cools, the cap’s vacuum valve draws coolant back in, keeping the system topped up and free of air. A healthy cap protects hoses, the heater core and water pump from pressure spikes and air pockets.

Good servicing practice is simple. Owners should have the cap inspected at routine services—look for hardening or cracking of the rubber seal, corrosion on the seat and a weak spring. A quick pressure test can confirm it holds its rated value (commonly around 90–110 kPa/13–16 psi—check the label under the bonnet or on the cap for the exact rating for the vehicle). Replace the cap if there’s any doubt, they’re inexpensive and can save a lot of grief. It’s sensible to renew the cap when doing a coolant change, or every 3–5 years/60,000–100,000 km in normal service.

• Only open the cap when the engine is completely cold.
• Match the correct pressure rating for this Highlander/Kluger variant.
• Clean the filler neck so the new seal beds properly.
• Hybrid variants also have a separate inverter cooling circuit—don’t confuse that reservoir cap with the engine’s radiator cap.

A fresh, correctly rated cap helps the Highlander hold temperature steady, improves coolant longevity and keeps the system free of air, which is exactly what’s wanted for reliable touring and city commuting alike.

Popular questions about the 2007 Toyota Highlander radiator cap

What pressure rating does the 2007 Highlander/Kluger radiator cap use?
Most use a cap in the 90–110 kPa (13–16 psi) range. The exact spec can vary by engine and market, so check the stamping on the existing cap or the sticker under the bonnet. Using a cap with the correct rating is crucial for proper boiling point and hose protection.

Where is the radiator cap located on this model?
It may be on the top of the radiator or on a remote filler neck near the upper radiator hose. Hybrids still have an engine cooling cap, but there’s also a separate inverter cooling reservoir—make sure the right cap is serviced.

How often should the radiator cap be replaced?
Have it inspected at every service. Replace at the first sign of seal damage, corrosion, weak spring pressure or unexplained coolant loss. As a rule of thumb, renewing it every 3–5 years or during a coolant change is cheap insurance.