Parts for your 2001 Toyota Crown-Radiator cap

2001 Toyota Crown Radiator Cap — What It Does, Why It Matters, and How to Look After It

Based on Toyota’s technical literature for the S170-series Crown (1999–2003) and the Toyota Electronic Parts Catalogue for JZS/GS171 variants, the vehicle is fitted with a pressurised radiator cap (commonly specified at 108 kPa/1.1 bar, e.g., Radiator Cap Sub-Assy 16401‑20353 or equivalent). The cooling system is designed to operate under pressure, so the radiator cap is very much relevant on a 2001 Toyota Crown.

On this model, the radiator cap seals the cooling system and regulates pressure. By raising the boiling point of the coolant, it helps the Crown handle high under‑bonnet temps without boiling over. The cap’s spring-loaded valve maintains the correct pressure, then gently vents excess to the overflow bottle as things heat up, and draws coolant back in as the engine cools. That constant push‑pull stabilises temperatures, protects gaskets and hoses, and keeps the alloy bits happier over the long haul.

When servicing a 2001 Toyota Crown, the radiator cap deserves the same attention as the thermostat and coolant. A cap with a weak spring or a perished seal can cause slow coolant loss, hard or collapsed hoses, poor cabin heat, or even overheating on a hot Kiwi or Aussie summer’s day. It’s smart practice to pressure‑test the cap whenever coolant is changed and any time there are cooling concerns.

• Only remove the cap when the engine is stone cold. Use a rag and open it slowly to release any residual pressure.
• Inspect the rubber seal and the valve for cracks, flattening, rust, or scale. Replace the cap if anything looks tired.
• Use the correct pressure rating (typically 1.1 bar/108 kPa for S170 Crowns, check the stamping on the cap or the under‑bonnet label).
• If the cooling system has been neglected or you’re switching coolant types, fit a new OEM‑spec cap at the same time.

As a rule of thumb, have the cap tested annually, and consider replacement every few years or at each major coolant service interval. Sticking with a quality OEM‑spec cap helps the big straight‑six or V6 in the Crown stay cool, comfortable, and reliable on long hauls.

Popular questions about the 2001 Toyota Crown radiator cap

What pressure cap should a 2001 Toyota Crown use?
Most S170 Crowns specify a 108 kPa (1.1 bar) cap. Owners should confirm by reading the stamping on the existing cap or checking the under‑bonnet sticker and parts catalogue for their exact engine code. Matching the correct rating is important for proper boil‑over protection and hose life.

Where is the radiator cap on a 2001 Toyota Crown?
It’s typically on the top tank of the radiator, near the driver’s side on right‑hand‑drive cars. Only open it when the engine is completely cold. If the vehicle uses a remote header tank in some markets, the pressure cap will be on that tank instead, serving the same job.

How can someone tell if the radiator cap is failing?
Look for crusty deposits around the neck, coolant pushing out of (or not returning from) the overflow bottle, hoses that go rock‑hard or collapse as it cools, rising temps in traffic, or a sweet coolant smell. A quick pressure test during servicing will confirm if the cap holds the specified pressure.