Parts for your 2013 Toyota Bb-Radiator cap

2013 Toyota bB radiator cap — does it have one, and what to know

Yes, the 2013 Toyota bB is fitted with a radiator cap. This is supported by Toyota’s technical literature for the bB (QNC20/QNC21 series, used in 2013), including the Cooling System section of the Toyota Repair Manual, which specifies a pressurised cap, and the Toyota Electronic Parts Catalogue listing a “Cap, Radiator” for these models. The bB Owner’s Manual also cautions against removing the radiator cap when hot—another clear indicator the system uses a conventional pressurised cap, typically around 1.1 bar (about 108 kPa).

For the 2013 Toyota bB, the radiator cap isn’t just a lid—it’s a little pressure manager that keeps the cooling system happy, especially in Aussie and Kiwi summers. By holding a set pressure, it raises the coolant’s boiling point so the engine can run at the right temperature without boiling over. It also houses a vacuum valve that draws coolant back from the overflow bottle as everything cools down, keeping air out and the system properly topped up.

As part of routine servicing, the radiator cap deserves a quick once-over. Under the bonnet, check the rubber seals for cracks or flattening, look for corrosion on the seat, and make sure the spring still has decent tension. A cooling-system pressure test (and cap test, if your workshop has the adaptor) is a simple way to confirm the cap still holds its rated pressure. If it doesn’t, it’s time for a replacement.

Symptoms of a tired cap can include gradual coolant loss, an overflow bottle that’s always brimmed or always empty, hoses collapsing as the engine cools, or creeping temperatures in traffic. Because the cap is cheap and critical, many techs will replace it preventatively every 5–7 years or around 100,000–150,000 kilometres, or sooner if testing says so. Always match the correct pressure rating for the 2013 Toyota bB—sticking with the factory spec (commonly ~1.1 bar) keeps the system balanced.

Safe handling matters: only open the cap stone-cold. Wrap it in a rag, crack it slowly to vent any residual pressure, and avoid breathing in vapour. When fitting a new cap, clean the filler neck, ensure the overflow hose is snug and unblocked, and twist the new cap fully home so both tabs engage. After any cooling work, run the engine to operating temp with the heater on, check for leaks, and confirm the overflow level sits between the marks once cooled. Use Toyota-approved pink Super Long Life Coolant and don’t mix types—consistency helps the seals and alloy components last.

• Inspect at every service, pressure-test if there are cooling complaints.
• Replace on test failure, visible damage, or age/kilometre thresholds.
• Match the correct pressure rating and cap style for the bB.

Popular questions about the 2013 Toyota bB radiator cap

Q1: What pressure rating should the 2013 Toyota bB radiator cap be?

A: Most 2013 Toyota bB models use a radiator cap around 1.1 bar (about 108 kPa). Always verify by reading the stamping on the existing cap, checking the under-bonnet label, or referring to Toyota’s repair data for the QNC20/QNC21 series. Using the correct rating maintains the designed boiling point and protects hoses, the heater core, and the radiator.

Q2: Where is the radiator cap on a 2013 Toyota bB?

A: It’s typically on the radiator filler neck under the bonnet, with a separate plastic overflow bottle nearby. On the bB, the overflow tank isn’t usually pressurised—the metal cap on the radiator does the pressure control. If in doubt, follow the top radiator hose to the radiator, the cap is usually right there.

Q3: How often should the radiator cap be replaced on a 2013 Toyota bB?

A: Inspect the cap at every service and pressure-test it if there are cooling concerns. As a rule of thumb, many workshops replace it every 5–7 years or 100,000–150,000 kilometres, whichever comes first. Replace immediately if the seal is cracked, the spring is weak, or it fails a pressure test—small money that can prevent big headaches.