Parts for your 2001 Daihatsu Yrv-Radiator cap

2001 Daihatsu YRV radiator cap — purpose and servicing

Based on the Daihatsu YRV (M2-series, 2000–2005) workshop manual’s cooling system description and the Daihatsu Electronic Parts Catalogue listings for K3-VE and K3-VET engines, the 2001 Daihatsu YRV is fitted with a pressurised radiator system that uses a radiator cap (typically around 0.9 bar/13 psi). So yes, a radiator cap is relevant and used on this model.

On the YRV, the radiator cap does more than just “seal the top.” It sets the system’s pressure so coolant can run hotter without boiling, helping keep temps steady on long Kiwi and Aussie drives, steep climbs, or stop–start traffic. It also manages coolant movement between the radiator and the overflow bottle as things heat up and cool down, using a tiny vacuum valve to draw coolant back in as the engine cools.

As part of routine servicing, the radiator cap is a small, affordable part that’s worth giving proper attention. A weak spring, perished seals, or a stuck vacuum valve can lead to annoying issues like slow overheating, mystery coolant loss, the overflow bottle constantly filling, or even hoses collapsing after shut-down.

• Check it at every coolant service: look for cracked rubber seals, corroded seat, sticky valve, or damaged cap ears.
• Pressure-test the cap annually (or if chasing cooling problems). Replace if it can’t hold the specified pressure.
• Use the correct pressure rating (around 0.9 bar for most YRV variants) and a quality cap that matches the radiator neck profile.

When replacing the cap on a 2001 YRV, only open it when the engine is stone-cold. Inspect and clean the radiator neck, make sure the overflow hose is snug and not brittle, and top the radiator directly before fitting the new cap. After warm-up, confirm the overflow bottle rises a little and then returns as it cools—this shows the vacuum valve is doing its job.

Practical replacement timing: swap the cap every 3–5 years or whenever coolant is renewed, especially if the car sees lots of hot-weather commuting, towing, or spirited runs. A fresh, correct-spec cap is cheap insurance for the YRV’s cooling system—and helps protect the head gasket, thermostat, and water pump from avoidable stress.

• Common symptoms of a dodgy cap: unexplained coolant loss, frequent overflow, overheating at highway speeds, sweet smell after parking, or collapsed upper hose after cool-down.

Popular questions about the 2001 Daihatsu YRV radiator cap

Where is the radiator cap on a 2001 Daihatsu YRV?
It sits on the radiator’s filler neck at the front of the engine bay, with a small hose running to the overflow bottle. Lift the bonnet and look near the top tank of the radiator—don’t open it hot.

What pressure radiator cap does the YRV use?
Most 2001 YRV models (K3-VE and K3-VET) use a cap around 0.9 bar (about 13 psi), as reflected in Daihatsu service literature and parts catalogues. Always match the cap rating to the original spec on the vehicle label or parts reference.

How often should the radiator cap be replaced?
It’s good practice to test it yearly and replace every 3–5 years, or any time the seals look tired or it fails a pressure test. If you’re doing a full coolant service, a fresh cap is a smart add-on.