Parts for your 2006 Toyota Crown-Radiator cap

2006 Toyota Crown radiator cap — what it does and how to look after it

Based on Toyota technical literature for the S180-series Crown (2003–2008)—including the Toyota Repair Manual cooling system section and entries in the Toyota Electronic Parts Catalogue (EPC) that list a “radiator cap sub‑assembly” for Crown variants—the 2006 Toyota Crown is fitted with a pressurised radiator cap. Most engines of this generation (e.g., GR‑series V6 and 3UZ‑FE V8 in Majesta) specify a cap typically rated around 108 kPa (1.1 bar), as stamped on the cap and noted in Toyota service procedures.

The radiator cap on this Crown isn’t just a lid. It’s a pressure regulator that lets the cooling system run at a higher pressure so the coolant’s boiling point climbs, helping the engine keep its cool on hot days and long motorway runs. Inside the cap are two valves: a pressure valve that vents to the overflow bottle when pressure climbs above spec, and a vacuum valve that draws coolant back in as the engine cools. That cycle keeps air out, minimises corrosion, and stabilises temperatures.

For servicing, the cap deserves a quick once‑over whenever coolant is checked. A technician will inspect the rubber seals for hardening or cracks, make sure the spring action feels firm, and look for staining or crust at the neck that hints at minor leaks. A cooling‑system pressure tester can confirm the cap holds the rated pressure and releases correctly. If it can’t meet spec, replacement is inexpensive insurance against overheating, hose collapse, or random coolant loss.

Good practice on a 2006 Crown is to inspect the cap at every service and replace it with the correct rating whenever the coolant is changed, the radiator is renewed, or at roughly the 5–7 year mark—whichever comes first. Toyota Super Long Life Coolant (pink) is common on this era, when that’s serviced (often at long intervals), pairing it with a fresh, genuine‑spec cap helps the lot work as designed. Always fit the rating shown on the original cap or under‑bonnet labels, going higher or lower can upset warm‑up, stress hoses, or trigger overflow.

• Only remove the cap when the engine is stone cold.
• Check for tell‑tales: dried pink/white residue, collapsed upper hose after cool‑down, or recurring overflow.
• Clean the filler neck gently, pitting or rough edges can stop a new cap sealing properly.

Popular questions about 2006 Toyota Crown radiator caps

What pressure rating does the 2006 Crown’s radiator cap use?
Technical listings for the S180 Crown commonly specify around 108 kPa (1.1 bar). The exact rating is stamped on the cap itself and can vary slightly by engine grade. Matching the stamp or confirming by VIN through parts catalogues is the safe bet.

How often should the radiator cap be replaced on a 2006 Crown?
It should be inspected at each service and pressure‑tested during cooling system work. Many workshops replace the cap preventatively every 5–7 years or whenever the coolant, radiator, or water pump is renewed, especially if there are any signs of seepage or weak spring tension.

Where is the radiator cap on a 2006 Crown?
On most S180 Crowns it sits on the radiator filler neck near the top tank, with a separate overflow bottle nearby. Some variants may present slightly different layouts, but the cap is typically right on the radiator under the bonnet.