Parts for your 2011 Honda Elysion-Radiator cap

2011 Honda Elysion radiator cap: what it does and how to look after it

Based on Honda service literature for the RR-series Elysion and listings in Honda’s electronic parts catalogue, the 2011 Honda Elysion is fitted with a conventional radiator cap (typical Honda 1.1 bar specification) on the cooling system. The cap is a service item with test procedures described in Honda workshop manuals under Cooling System and Radiator Cap Test.

On the Elysion, the radiator cap does a lot more than just seal the top. It holds pressure in the cooling system so the coolant’s boiling point climbs, keeping temperatures stable when they’re towing, stuck in traffic, or cruising up a mountain pass. Inside the cap is a spring-loaded pressure valve and a vacuum valve. When things get hot, excess pressure vents to the overflow bottle, as the engine cools, the vacuum valve draws coolant back in so there’s no air sneaking into the system. That’s how the van avoids overheating and hose collapse without any dramas.

Good servicing practice is to treat the cap like a safety device. Only remove it when the engine is stone-cold. If it’s time for a coolant change (use Honda Type 2 or a high-quality equivalent that meets the spec), this is the right moment to inspect or replace the cap. Look for perished rubber seals, a sticky or wobbly spring, damaged tabs, or crusty deposits around the filler neck. A workshop can pressure-test the cap, if it can’t hold its rated pressure, it’s due for replacement. Stick with the correct pressure rating (commonly 1.1 bar for Honda) to protect the alloy radiator, water pump, and heater core.

• Common clues the cap’s had it: gradual coolant loss with no obvious leaks, overheating at highway speeds, hoses that go rock-hard then collapse as it cools, and white or green crust around the cap neck.
• Handy tip: keep the overflow hose clear and seated tight, the vacuum return relies on it.

Swapping the cap is quick and inexpensive, and it can save a radiator or head gasket. For an Elysion that’s getting on in years, replacing the cap proactively every 5–7 years, or any time it fails a test, is smart preventative maintenance under the bonnet.

Popular questions about the 2011 Honda Elysion radiator cap

Where is the radiator cap on a 2011 Honda Elysion?
It’s located at the cooling system’s filler neck, typically at the top of the radiator or on the engine-side filler neck depending on variant. Always check the owner’s manual diagram and only open it when the engine is cold.

What pressure cap should it use?
Honda commonly specifies a 1.1 bar (approximately 108 kPa) cap for the Elysion. Use a quality cap that matches the original spec to maintain correct boiling point and system protection.

When should the radiator cap be replaced?
Replace it if it fails a pressure test, shows damaged seals or corrosion, or if you’re chasing unexplained coolant loss. As preventative maintenance, many techs replace the cap every 5–7 years on older vehicles.