Parts for your 2020 Toyota Vitz|yaris-Radiator cap

2020 Toyota Vitz/Yaris radiator-cap — what it is, where it went, and what to look after

For the 2020 Toyota Vitz/Yaris, a traditional radiator-cap on the radiator neck isn’t used. Toyota’s own technical information for the 2020 Yaris platform (as sold in Australia and New Zealand) shows the cooling system is a sealed design with a pressurised coolant reservoir (also called a degas or reserve tank). The pressure cap sits on that reservoir, not on the radiator itself. This is reflected in Toyota workshop literature and the Toyota Electronic Parts Catalogue, which list a “radiator reserve tank cap” rather than a separate radiator filler cap for these models.

Why the change? Modern compact Toyotas position the filler and pressure point high on a remote tank. That helps keep air out of the system, improves self-bleeding, and simplifies service access. It also reduces hot surfaces that technicians or owners might touch under the bonnet, and it packages better in tight engine bays.

• Better air separation: mounting the cap on a high tank lets air migrate up and out more reliably.
• Simpler servicing: filling and bleeding are done at one point — the reservoir.
• Safety: fewer chances of someone opening a cap on a hot radiator.
• Packaging: frees up space around the radiator and improves crash packaging and airflow.

So, while owners might search for a 2020 Toyota Vitz/Yaris “radiator-cap”, the relevant service part is actually the coolant reservoir pressure cap. It performs the same core jobs a traditional radiator cap used to do: it holds pressure to raise the coolant’s boiling point, and it controls vacuum as the system cools so coolant is drawn back in, not air.

Typical Toyota caps on these models are around 108 kPa (about 1.1 bar), but the correct rating is printed on the cap and confirmed in Toyota service information. Sticking to the specified rating matters — too low and coolant can boil early, too high and hoses and the heater core can be stressed.

Maintenance-wise, owners should have the reservoir cap inspected at regular services. Look for a brittle or cracked rubber seal, signs of dried pink coolant (Toyota Super Long Life Coolant) around the neck, a sticky or weak spring, or hoses that collapse as the engine cools (a hint the vacuum valve isn’t working). Replace the cap if any of these show up, whenever cooling system work is done, or proactively after years of heat cycles. Always open the cap only when the engine is stone cold.

Use Toyota-approved coolant (pink premix) and follow the bleeding procedure in the workshop manual after any coolant change. That keeps the system air-free, protects the alloy components, and lets the new cap do its job properly.

Popular questions about the 2020 Toyota Vitz/Yaris radiator-cap

Where is the radiator cap on a 2020 Toyota Vitz/Yaris?
There isn’t a cap on the radiator itself. The pressure cap is on the coolant reservoir (degas bottle) mounted high in the engine bay. It’s the one with the pressure warning label — only remove it when the engine is completely cold.

What pressure rating cap does the 2020 Yaris use?
Most use a cap around 108 kPa (about 1.1 bar). Check the stamp on the existing cap or Toyota service data for the exact spec by VIN. Using the wrong rating can lead to boil-over or undue stress on hoses and the heater core.

When should the reservoir cap be replaced?
Toyota doesn’t set a strict interval, but it should be replaced if the seal is cracked, the spring’s weak, there are leaks or dried coolant around the neck, recurring low coolant with no external leak, or hoses that collapse after cooldown. Many owners choose to renew it during major cooling system service for peace of mind.