Parts for your 2007 Toyota Vitz|yaris-Radiator cap

2007 Toyota Vitz/Yaris Radiator Cap — What It Does And How To Look After It

Yes, a radiator cap is fitted and relevant on the 2007 Toyota Vitz/Yaris (XP90 series). Toyota’s service literature for the XP90 cooling system includes radiator cap inspection and pressure testing, and the Toyota Electronic Parts Catalog lists a “Cap Sub-Assy, Radiator” for NCP90/NCP91 variants (commonly 16401-31650, cap rating around 0.9–1.1 bar). On this model, the cap sits on the filler neck in the engine bay (near the upper radiator hose), with a separate translucent overflow bottle alongside.

The radiator cap isn’t just a lid. It’s a pressure regulator and one-way valve that lets the cooling system run under pressure, lifting the coolant’s boiling point so it can handle Aussie and Kiwi summer heat without boiling. As the engine cools down, the cap’s vacuum valve draws coolant back from the reservoir, keeping the system topped up and free of excess air. A healthy cap helps prevent overheating, hose collapse, and nuisance coolant loss.

As part of regular servicing, it’s smart to check the cap at each service interval and replace it if it’s tired. Use a quality cap with the correct pressure spec (typically 88–108 kPa/0.9–1.1 bar as marked on the cap). Many owners pair cap replacement with coolant service (Toyota Super Long Life Coolant, pink). Initial SLLC change is often around 160,000 km or 10 years, then every 80,000 km or 5 years—swapping the cap at those times is cheap insurance.

• Signs the cap is due: crusty or pink/white deposits on the neck, cracked or flattened rubber seal, weak spring, random temperature spikes, or a radiator hose that collapses as the engine cools.
• Quick check and replace:
  1. Only open the cap stone-cold. Wrap a rag over it and turn slowly to release any residual pressure.
  2. Inspect the rubber gasket and spring, look for neck corrosion.
  3. Top the reservoir to the “FULL COLD” line with the correct coolant mix.
  4. Fit the new cap and lock it fully. Start the engine, heater on HOT, and let it idle to purge air. Recheck the reservoir level after a short drive.

If temperatures still wander or there’s no cabin heat, have a workshop pressure-test the cap and system. A correct-spec cap helps the 2007 Vitz/Yaris stay cool under load, in traffic, and on long open-road runs.

FAQs

What pressure radiator cap does a 2007 Toyota Vitz/Yaris use?

Most 2007 Vitz/Yaris models use a cap rated around 0.9–1.1 bar (88–108 kPa). Check the stamp on your existing cap or the under-bonnet label. Genuine Toyota caps for the XP90 commonly list 1.1 bar, some markets specify 0.9 bar. Always match the rating to the vehicle’s spec.

Where is the radiator cap on a 2007 Yaris?

It’s on the metal filler neck near the upper radiator hose, under the bonnet. Don’t confuse it with the plastic overflow bottle cap—the pressurised cap sits on the filler neck, the overflow bottle has a simple non-pressurised lid.

How often should the radiator cap be replaced?

Have it inspected every service and replace it if seals are cracked, the spring feels weak, or there are cooling issues. Many owners replace the cap during coolant changes—about 160,000 km/10 years initially with Toyota SLLC, then every 80,000 km/5 years—or sooner if any faults show up.