Parts for your 2021 Honda Cr-v-Radiator cap

Radiator cap on a 2021 Honda CR‑V: what it is and how to look after it

Yes, the 2021 Honda CR‑V uses a radiator cap. This is confirmed by Honda’s technical literature: the Owner’s Manual warns not to open the radiator cap when hot and instructs coolant checks at the reserve tank, while the Honda Service Manual procedure for coolant replacement includes removing and refitting the radiator cap during bleeding. Honda’s genuine parts catalogue also lists a “Cap, Radiator” (1.1 bar/16 psi) for the 2017–2022 CR‑V range.

On the CR‑V, the radiator cap sits on the top tank of the radiator, under the bonnet near the upper grille shroud. It’s a spring‑loaded pressure cap that seals the cooling system, lets it build pressure (raising the coolant’s boiling point), and then relieves excess pressure safely to the reserve tank. As the engine cools, its vacuum valve draws coolant back from the tank so the system stays topped up. When it’s doing its job properly, the cap helps keep operating temperatures steady, prevents boil‑over, and protects hoses and the radiator from overpressure.

Good servicing habits make a big difference. At routine services (or any time the coolant is replaced), a technician should:

• Inspect the cap’s rubber seals for cracks, hardening, or nicks, and check the spring for smooth, firm resistance.
• Pressure‑test the cap to the specified rating (about 1.1 bar/16 psi) and replace it if it won’t hold pressure.
• Check the radiator neck for corrosion or damage that could stop the cap sealing properly.

Typical warning signs of a tired cap include unexplained coolant loss, a sweet coolant smell after driving, hoses that collapse as the engine cools, overheating at highway speeds, or a reserve tank that either overflows or never seems to refill the radiator. Because the part is inexpensive, many workshops treat a cap replacement as cheap insurance at major coolant services—think roughly every 5–7 years or around 100,000–120,000 kilometres, or immediately if it fails a pressure test.

Important safety tip: never remove the radiator cap when the engine is hot. Let the car cool completely, protect hands with a rag or gloves, and turn the cap slowly to the first stop to vent any residual pressure before removing it. Use a genuine‑spec 1.1 bar cap to match Honda’s design—fitting the wrong pressure rating can cause cooling issues.

Popular questions

What pressure rating should the 2021 CR‑V radiator cap be?

The factory spec is about 1.1 bar (16 psi). That rating balances a higher boiling point for effective cooling with protection for hoses and the radiator. Using a cap with a lower rating can invite boil‑over, going higher risks stressing components and masking underlying issues.

Where is the radiator cap on a 2021 CR‑V?

It’s mounted on the top of the radiator, generally near the centre‑right under the plastic upper shroud. Lift the bonnet, remove the plastic clips or reach under the cover if required, and you’ll see the metal cap with the pressure warning labels. Only touch it when the engine is completely cool.

How often should the radiator cap be replaced?

There’s no strict time limit, but it should be inspected at every service and pressure‑tested whenever the coolant is changed. Many techs replace it proactively every 5–7 years or around 100,000–120,000 kilometres. Replace immediately if seals are perished, it won’t hold pressure, or there are cooling system symptoms.