Parts for your 2015 Volvo Xc60-Radiator cap

2015 Volvo XC60 radiator cap — what’s actually fitted

For the 2015 Volvo XC60 there isn’t a traditional radiator cap on the radiator at all. Instead, the vehicle uses a sealed cooling system with a pressurised coolant expansion tank (also called a degas bottle) and a pressure cap on that tank. This setup means the term “radiator cap” isn’t relevant for this model — the service item is the expansion tank pressure cap.

Technical sources supporting this: Volvo Owner’s Manual (XC60 MY2015) directs coolant level checks and top-ups at the expansion tank, not the radiator, Volvo VIDA/Workshop Information for the P3 platform describes a degas-type cooling system with a remote pressure cap (approx. 150 kPa/1.5 bar), and Volvo parts catalogues for MY2015 XC60 list a coolant expansion tank with a pressure cap while the radiator itself has no cap.

• System design: The XC60’s “degas” system routes air and hot coolant to a high-mounted expansion tank, where the cap controls pressure and venting. No filler neck is built into the radiator.
• Better bleeding and reliability: Locating the cap at the highest point improves self-bleeding, reduces aeration, and stabilises operating temperature.
• Safety and packaging: Keeping the cap away from the radiator core reduces scald risk and frees up front-end packaging for crash protection and airflow.

What matters for servicing is the condition and rating of the expansion tank cap. It’s a pressure valve that raises the coolant’s boiling point and holds system pressure, if it weakens, the engine can run hotter, push coolant out, or draw in air as it cools. Typical clues the cap is tired include a sweet coolant smell, crusty residue around the cap, hardened or cracked seal, collapsed hoses after cooldown, or intermittent overheating.

Advice for owners: Inspect the cap at every service, checking the rubber seal, threads, and the tank neck for cracks. Replace the cap if it fails a pressure test, shows visible wear, or as preventive maintenance every few years, especially in hot climates or high-kilometre use. Always match the specified Volvo pressure rating (around 150 kPa/1.5 bar) and use approved coolant when topping up. Only ever open the cap when the engine is fully cold, a hot system can release scalding pressure.

Practical tip: Top up to the MAX mark on the expansion tank, not the radiator, and avoid overfilling. Hand-tighten the cap firmly until it seats — no tools needed.

Where is the “radiator cap” on a 2015 Volvo XC60?

There isn’t one on the radiator. The pressure cap is on the coolant expansion tank, usually a translucent plastic bottle high on the right-hand side of the engine bay. It’s the cap you open for checks and top-ups — only when cold.

What pressure rating should the XC60 coolant cap have, and why does it matter?

Around 150 kPa (1.5 bar) is specified for this generation. Using the correct rating maintains the right boiling point and hose pressures. A lower rating can cause boil-over, a higher rating can overstress hoses, the tank, or the radiator.

How often should the coolant cap be replaced or tested?

Have it inspected at each service. Replace it if the seal is cracked, it fails a pressure test, there’s coolant crusting, or after roughly 5–7 years as preventive maintenance. It’s an inexpensive part that can prevent costly overheating issues.