Parts for your 2017 Toyota C-hr-Radiator cap

Radiator cap for a 2017 Toyota C-HR — what’s actually fitted?

Short answer: the 2017 Toyota C-HR doesn’t use a traditional radiator cap on the radiator. Instead, it runs a sealed, pressurised cooling system where the pressure cap sits on the translucent coolant reservoir (also called a degas or expansion tank). That reservoir cap does the same job as an old-school radiator cap, but it’s the only cap the owner will touch under the bonnet.

This isn’t guesswork. Technical sources show the setup is fill-and-bleed via the reservoir, not the radiator neck. The 2017 C-HR Owner’s Manual (AUS/NZ) explains checking and topping up coolant at the reservoir and warns against opening the reservoir cap when hot—there’s no instruction to remove a radiator cap. Toyota’s service procedures for the C-HR cooling system also specify filling through the reserve tank and bleeding air from the system, again with no radiator-neck cap in the steps. Genuine parts catalogues list a pressurised reservoir (with cap) and a radiator without a serviceable cap on the neck for these models.

Why ditch the old radiator cap? It’s mostly about packaging, reliability, and safety. By putting the pressure cap on a remote, high-mounted reservoir, the system self-degasses better, keeps the highest point easy to access, and reduces scald risk when checking levels. It also suits modern front-end packaging on TNGA-based models and supports long-life pink Toyota Super Long Life Coolant (SLLC) intervals.

What should a C-HR owner look after instead? The reservoir cap. It’s the pressure valve that raises the boiling point and lets the system breathe to and from the tank. If its rubber seal hardens or the spring weakens, the cooling system can run below spec pressure, causing early boil-over, hose collapse, or slow coolant loss. At routine services, it’s smart to check that cap for cracked rubber, sticky movement, or crusty deposits, and confirm the pressure rating stamped on the cap. Many Toyota caps in this era are around 108 kPa (1.1 bar), but the owner should match the exact spec on the vehicle. Always open only when the engine is stone cold, and top up with pink Toyota SLLC premix. Toyota typically specifies an initial coolant change at about 160,000 km or 10 years, then every 80,000 km or 5 years thereafter—confirm in the C-HR owner’s manual for the exact engine and market.

Technical sources referenced:

• Toyota C-HR (2017) Owner’s Manual (AUS/NZ) — Engine coolant section (reservoir-based checks and warnings)
• Toyota C-HR Repair/Service Procedures — Cooling system fill and bleed via reserve tank
• Toyota Genuine Parts Catalogue — Pressurised reservoir and cap listed, radiator assembly without service cap on neck

Popular questions

Where is the radiator cap on a 2017 Toyota C-HR?
There isn’t a cap on the radiator itself. The pressure cap lives on the plastic coolant reservoir (expansion/degas bottle). That’s the only cap to open for checks, top-ups, or bleeding—always when the engine is cold.

What pressure cap does the 2017 C-HR use?
Check the marking on the existing cap and match it. Many Toyota passenger models around this period run about 108 kPa (1.1 bar), but the correct rating can vary with engine and market. Using the wrong pressure can cause leaks, poor warm-up, or early boil-over, so stick with genuine or OEM-quality to the marked spec.

How often should the cap or coolant be replaced?
Have the reservoir cap inspected at every service for rubber condition and spring action, replace if it’s brittle, cracked, or not holding pressure. For coolant, Toyota Super Long Life Coolant is typically due at around 160,000 km or 10 years initially, then every 80,000 km or 5 years. Always confirm intervals in the C-HR owner’s manual for the specific engine.