Parts for your 2013 Toyota Vitz|yaris-Radiator cap

2013 Toyota Vitz/Yaris radiator cap — purpose, upkeep, and tips

Based on technical sources, the 2013 Toyota Vitz/Yaris (XP130 series: KSP13#, NCP13#, NSP13#) is equipped with a conventional pressurised radiator cap fitted to the radiator neck. Toyota’s Repair Manual for this generation includes the “Inspect Radiator Cap Sub‑Assembly” procedure, and Toyota’s Electronic Parts Catalogue lists a “Cap, Radiator” for these models (common specification 1.1 bar/108 kPa, e.g., cap sub‑assembly part references such as 16401‑31650 or 16401‑20353). The Owner’s Manual also warns against removing the radiator cap when hot. Taken together, these technical references confirm that the radiator cap is fitted and relevant on the 2013 Vitz/Yaris.

On this Yaris, the radiator cap does far more than just cover a hole. It holds a set pressure (about 108 kPa/1.1 bar) so the coolant’s boiling point is raised, which helps keep the engine at a steady temperature under Aussie and Kiwi conditions. The spring-loaded seal also allows excess pressure and expanding coolant to flow to the overflow bottle when the engine is hot, then draws coolant back in as things cool down via the vacuum valve. That closed-loop action prevents air from sneaking into the system, protects hoses and the heater core, and helps the thermostat behave properly.

As part of regular servicing, the cap deserves a quick check under the bonnet. Look for a perished rubber seal, a sticky or corroded spring, crusty deposits on the cap or filler neck, or a cracked vacuum valve. If a pressure tester is on hand, confirm it holds the rated pressure and that the vacuum valve opens smoothly. A tired cap can cause annoying symptoms—coolant loss into the overflow bottle, random overheating on a hot day, a collapsed top hose after cool-down, or weak cabin heat.

Replacement is simple and inexpensive, so it’s smart preventative maintenance at around 5 years/100,000 km, or sooner if there’s been an overheat event or the cap fails a test. Use the correct pressure rating (typically 1.1 bar for this model) and the right cap height/profile so it seals the radiator neck properly. Pair it with the correct Toyota Super Long Life Coolant and never open the cap when hot. After fitting a new cap, confirm the overflow hose is snug, coolant is at the correct cold mark, and there are no drips around the neck. A quick once‑over each service keeps the cooling system happy and the Yaris running sweet.

• Inspect at every service, replace at ~5 years/100,000 km or if testing fails.
• Use a 1.1 bar cap that matches the radiator neck profile and seal height.
• Check the overflow hose and filler neck for cleanliness and good condition.

Technical references noted: Toyota Repair Manual (XP130) “Inspect Radiator Cap Sub‑Assembly”, Toyota Electronic Parts Catalogue listing “Cap, Radiator” for 2011–2014 Yaris/Vitz (e.g., 16401‑31650/16401‑20353), Owner’s Manual safety cautions regarding radiator cap removal when hot.

Popular questions about 2013 Toyota Vitz/Yaris radiator caps

What pressure rating is correct for a 2013 Toyota Vitz/Yaris radiator cap?

Most 2013 Vitz/Yaris models use a 1.1 bar (108 kPa) radiator cap. That rating keeps the coolant’s boiling point high enough for normal driving and towing in local conditions.

Always confirm by reading the stamping on the original cap or checking the under‑bonnet label and parts catalogue for the specific engine code, as regional specs can vary slightly.

How often should the radiator cap be replaced?

Have it inspected at every service and pressure‑tested if there are cooling complaints. As a rule of thumb, replace around 5 years/100,000 km, or immediately after any overheating incident.

If the seal looks cracked, the spring action feels rough, or it won’t hold its rated pressure, swap it out—caps are inexpensive insurance against overheating and coolant loss.

What are the signs of a failing radiator cap on a Yaris?

Watch for coolant frequently pushing into the overflow bottle, random temperature spikes on long climbs, a collapsed top hose after cool‑down, or white crust around the filler neck.

Heater performance dropping off or needing frequent top‑ups can also point to a weak cap allowing air in. A quick pressure test will confirm the cap’s health.