Parts for your 2022 Mazda Cx-5-Radiator cap

2022 Mazda CX‑5 radiator cap — is it actually a thing?

Short answer: a traditional radiator-cap on the radiator itself isn’t used on the 2022 Mazda CX‑5. Mazda’s KF‑series CX‑5 (including the 2022 update) runs a sealed radiator and a pressurised coolant reserve/degas tank, with the pressure cap fitted to that tank instead. This layout is documented in Mazda’s 2022 CX‑5 Owner’s Manual cooling-system instructions (which point owners to check and top up at the coolant reserve tank), in Mazda’s workshop manual component diagrams (listing a “coolant reserve tank cap/pressure cap” and a sealed radiator with no filler neck), and in Mazda’s electronic parts catalogue for the KF platform (showing a reserve tank cap as the service part, with no separate radiator neck cap).

Why Mazda doesn’t use a radiator-cap on the CX‑5’s radiator comes down to how modern cooling systems are designed. The pressurised degas tank is the highest point and the only fill point, so the system self‑bleeds air more effectively and stays topped up. It also helps packaging under a lower bonnet line and improves crash safety by removing a hot, pressurised cap from the radiator face. With fewer joints and a sealed radiator core, there’s one less place to leak, and service routines are simpler: coolant checks and fills happen at the tank only.

What many people still call the “radiator cap” on this model is actually the coolant reserve/degas tank cap — that’s the pressure cap doing all the work. If it’s being replaced, it’s important to match Mazda’s specified pressure rating and seal design. A tired cap can cause hard or collapsing hoses, coolant loss into the overflow, overheating in traffic, or a sweet smell under the bonnet. It should only ever be opened when the engine is stone cold. If a top‑up is needed, use Mazda‑approved long‑life coolant (often FL22) or a direct equivalent, avoid mixing unknown coolants and use demineralised water only for small emergency top‑ups.

• The radiator itself has no cap or filler neck on the 2022 CX‑5.
• The only cap to inspect/replace is on the coolant reserve/degas tank.
• Check the cap at each service, replace if seals are cracked, the spring feels weak, or there are signs of leakage.

Does the 2022 CX‑5 have a radiator cap I can remove?

No. The radiator is sealed. The removable, pressurised cap is on the coolant reserve/degas tank — that’s the cap to check, open (only when cold), and replace if needed.

Where is the coolant cap located on a 2022 CX‑5?

Under the bonnet on the coolant reserve/degas tank. Depending on engine variant it’s typically mounted high and to one side of the bay. It’s a black cap with warning text — don’t open it hot.

What cap should be used and how often should it be replaced?

Use a genuine Mazda cap or a quality equivalent that matches Mazda’s pressure rating for the KF CX‑5. Inspect at every service for perished seals, staining, or weak spring tension. Many shops treat the cap as a preventative replacement item around major coolant services or if any symptoms of pressure loss appear.