Parts for your 2007 Honda Fit-Radiator cap

2007 Honda Fit radiator cap — what it does and when to replace it

Yes, the 2007 Honda Fit (also known as Jazz in NZ/AU) uses a proper radiator cap on the radiator neck. Honda’s factory Service Manual for the GD-series Fit/Jazz cooling system, along with Honda EPC (Electronic Parts Catalogue) listings, specify a pressurised cap with a relief pressure around 93–123 kPa (roughly 1.1 bar, 13–18 psi). Genuine Honda parts catalogues commonly list this as a 1.1 bar cap, often supplied under part numbers such as 19045-PAA-A01 or later supersessions. The overflow bottle on this model is non‑pressurised, system pressure control is handled by the radiator cap itself.

On this Fit, the radiator cap’s job is to hold a set pressure so the coolant’s boiling point is raised, helping keep temperatures steady on hot days, steep climbs, or when the air‑con is giving it heaps. Inside the cap, a pressure valve vents excess pressure into the reservoir when things heat up, and a vacuum valve draws coolant back into the radiator as it cools. That two‑way action keeps air out, hoses from collapsing, and hot spots from forming in the alloy head.

• Common symptoms of a crook cap: gradual coolant loss with no obvious leak, gurgling after shutdown, overheating at idle, collapsed upper hose after cool‑down, or a sweet coolant whiff under the bonnet.
• What to fit: stick with a 1.1 bar cap that meets Honda spec, genuine or quality aftermarket is fine if it matches the rating and seal design.

Good servicing habit for a 2007 Fit is to check the radiator-cap at every coolant service or major interval. Look for a perished rubber seal, a sticky spring, cracked or corroded sealing faces, and distorted tabs. If anything looks tired—or if overheating or overflow issues pop up—replace the cap. Many techs in Australia and New Zealand treat the cap as a low‑cost preventative item every 5 years or 100,000 km, especially in hot or coastal climates.

1. Only open the cap when the engine is stone cold. Use a rag and turn to the first detent to release any residual pressure.
2. Inspect and clean the filler neck, corrosion or burrs can stop the seal from working.
3. Install the new 1.1 bar cap and ensure it locks fully. Top up the radiator with Honda Type 2 coolant (premix), set the reservoir to “MAX”, run the engine with heater on hot, and recheck levels once cooled.

A sound radiator cap is cheap insurance for the Fit’s alloy engine—small part, big job, worth doing right.

What pressure rating is correct for a 2007 Honda Fit radiator cap?

Honda’s technical data for the GD-series specifies a relief pressure around 93–123 kPa (about 1.1 bar, 13–18 psi). Using the correct rating keeps the boiling point high and the system stable. Avoid “high‑pressure” caps that don’t match spec, as they can stress hoses and the radiator.

How often should the radiator cap be replaced?

Have it inspected at each coolant service. In Aussie and Kiwi conditions, many workshops replace the cap proactively every 5 years or 100,000 km, or sooner if the seal hardens, the spring weakens, or overheating/overflow symptoms show up.

Can a faulty radiator cap cause overheating or coolant loss?

Absolutely. A weak cap can let coolant boil earlier and vent to the overflow, while a stuck vacuum valve can draw in air instead of coolant during cool‑down. Both situations can lead to overheating, air pockets, and gradual coolant loss.