Parts for your 2015 Subaru Exiga-Radiator cap

2015 Subaru Exiga radiator-cap

Based on Subaru’s factory technical documentation and parts listings, the 2015 Subaru Exiga (including the Crossover 7 with the FB25 engine) uses a pressurised radiator cap. On these later FB-series cooling systems the cap is mounted on the pressurised reservoir/header tank rather than directly on the radiator. References include the Subaru Factory Service Manual for FB25 Cooling (Cooling System > Reservoir Tank and Radiator Cap, valve opening pressure approx. 108 kPa/1.1 bar) and Subaru parts catalogues listing a genuine “Cap Assy – Radiator” for Exiga models of this era. So yes, a radiator cap is relevant and fitted.

On the Exiga, the radiator cap’s job is deceptively simple but critical. It holds system pressure to lift the coolant’s boiling point, keeps the FB25 happy under load, and uses a two-way valve so coolant can expand to the overflow bottle and then be drawn back in as it cools. That pressure control helps prevent localised boiling, hose collapse, and cavitation around the water pump. When the cap’s spring weakens or the seals harden, small leaks, intermittent overheating, or a low coolant level can follow.

As part of regular servicing, it’s smart to inspect the cap at every service and replace it whenever there are signs of age, damage, or cooling-system work being done. Many workshops in Australia and New Zealand will swap the cap preventatively every few years or at major coolant services to avoid nuisance issues. Stick with the OE-spec pressure rating (about 1.1 bar/108 kPa) — going lower can invite boil-over, and going higher can stress hoses, the radiator, or the heater core.

• Quick checks: look for cracked rubber seals, corroded or pitted seating surfaces, sticky or weak spring action, and crusty deposits on the neck.
• Replacement tips: only open the cap when the engine is stone cold, use a rag and turn slowly to release any residual pressure. Clean the neck, lightly wet the new seal with fresh coolant, and tighten firmly.
• After fitting: top up the pressurised reservoir to the “FULL” mark with Subaru-approved coolant, run the engine to operating temp with the heater on, and recheck levels once cooled.

If the Exiga is running hotter than usual, the upper hose stays soft at high temp, or there’s coolant smell after drives, the cap is a cheap first part to test or replace. A healthy, correct-spec cap is small money that protects a very big job.

FAQs

Where is the radiator cap on a 2015 Subaru Exiga?
It’s on the pressurised reservoir/header tank (usually the highest point in the engine bay), not on the radiator itself. This design makes bleeding easier and keeps the cap at the true high point of the cooling system.

What pressure radiator cap does it use?
Use an OE-spec cap rated around 108 kPa (1.1 bar). Matching the factory pressure is important to maintain the intended boiling point and protect hoses and the heater core.

How often should the radiator cap be replaced?
Inspect at every service. Replace at the first sign of seal wear, corrosion, weak spring action, or if you’re doing a coolant service. Many local workshops will replace preventatively every few years to avoid overheating dramas.