Parts for your 2013 Toyota Vitz|yaris-Radiator cap

2013 Toyota Vitz/Yaris Radiator Cap – What it does and how to look after it

Used: Yes. Technical sources including the Toyota Electronic Parts Catalogue (listing a “Cap Sub-Assembly, Radiator” for XP130 Vitz/Yaris, 2011–2014) and the Toyota Repair Manual cooling system section confirm the 2013 Toyota Vitz/Yaris is built with a pressure-type radiator cap. Depending on engine variant and market, the cap sits on the radiator filler neck or on a pressurised surge/expansion tank, but the function and service needs are the same.

The radiator cap on a 2013 Vitz/Yaris is a small but crucial bit of kit. It seals the cooling system and holds pressure (typically around 0.9 bar/13 psi), which lifts the coolant’s boiling point so it can carry heat away from the engine without boiling under the bonnet. Inside the cap are two valves: a pressure valve that vents excess pressure to the overflow bottle, and a vacuum valve that draws coolant back in as the system cools. That cycle keeps the system full, stable, and happy.

For servicing, the cap deserves a quick once-over at each service or at least yearly. Look for perished rubber seals, a sticky or gritty spring, crusty deposits, or a distorted seating face on the filler neck. If the upper radiator hose keeps collapsing after cool-down, if there’s unexplained coolant loss, or if overheating shows up in stop–go traffic, a tired cap is a likely suspect. Most owners are well served replacing the cap every five years, sooner if there are any of those tell-tales.

Safety matters: never pop the cap when it’s hot. Let it cool right down, then wrap a rag over the cap and open slowly to bleed off any residual pressure. Match the replacement cap’s pressure rating to the factory spec (around 0.9 bar for most XP130 variants). A genuine or high-quality OEM-equivalent cap is worth it—cheapies can leak or stick. When refilling, use Toyota Super Long Life Coolant (pink) premix and burp the system so air doesn’t get trapped.

• Inspect: seals, spring action, deposits, clean seating face.
• Replace: at 5 years or at first sign of wear, with the correct pressure rating.
• Operate: only when cool, ensure the cap clicks home firmly.

Popular questions

What pressure rating does the 2013 Vitz/Yaris radiator cap use?
Most XP130 Vitz/Yaris variants run a 0.9 bar (13 psi) cap. Markets and engines can vary slightly, so the sure bets are the existing cap’s stamping, the Toyota EPC listing for the VIN, or the workshop manual specification.

How often should the radiator cap be replaced?
It should be inspected at every service and typically replaced about every five years. If there are signs of hardened rubber, coolant crust, or hose collapse after cool-down, replace it sooner.

Can a dodgy cap cause overheating?
Yes. If the cap can’t hold pressure, coolant can boil earlier and push into the overflow, leading to overheating and loss of coolant. A stuck vacuum valve can also trap air, which hurts heater performance and cooling efficiency.