Parts for your 2008 Subaru Exiga-Radiator cap

2008 Subaru Exiga radiator cap — what it does and how to look after it

Yes, the 2008 Subaru Exiga does use a radiator cap — though it’s not on the top of the radiator itself. On the YA-series Exiga, Subaru runs a pressurised cooling system with the pressure cap fitted to the engine’s header/expansion tank (sometimes called the reservoir) rather than the radiator neck. This layout is documented in Subaru’s YA Exiga workshop manual (Cooling System section) and reflected in Subaru’s genuine parts catalogue, which lists a pressure cap for the pressurised reservoir while the radiator has no filler neck.

That cap is a small part doing a big job. It seals the system and holds a set pressure so the coolant’s boiling point is raised, helping the Exiga cope with hot days, long hills, and towing. Inside the cap is a spring-loaded pressure valve that lets excess pressure vent to the overflow hose, plus a vacuum valve that draws coolant back as the engine cools. If the cap gets tired, the system can’t hold pressure, which can lead to overheating, coolant loss, or hoses collapsing as it cools down.

For routine servicing, it’s smart to inspect or test the cap any time coolant is changed, or yearly if the vehicle sees tough use. A workshop can pressure-test the cap with a simple hand tool to confirm it holds the specified kPa rating. When replacing, always match the exact pressure rating printed on your current cap or as specified in the Subaru service information for your engine variant. Using the wrong rating can cause nuisance overheating or stress the system.

• Common signs it’s time: crusty deposits on the cap seat, perished rubber seal, spring movement that feels weak or rough, random coolant loss, or temps creeping up on climbs.
• Quick tips: only open the cap stone cold, crack it slowly to release any residual pressure, inspect the overflow hose for splits, and top up via the pressurised reservoir, not the plastic overflow bottle.

Location-wise, owners will find the cap on the alloy or black plastic pressurised tank near the intake manifold under the bonnet. If the cap’s original and the Exiga is a decade or more old, proactive replacement is inexpensive insurance. Stick with a quality cap that meets the Subaru spec, seat it squarely, and keep the sealing surfaces clean. Done right, the cooling system stays happy, the heater works properly, and weekend trips across the Tasman or up the coast are a breeze.

• Where is the radiator cap on a 2008 Subaru Exiga?
  The Exiga’s pressure cap sits on the pressurised header/expansion tank in the engine bay, not on the radiator itself. Look near the intake manifold for the small tank with a metal-style safety cap.
• What pressure rating cap should it use?
  Use the exact kPa rating shown on your existing cap or as listed in Subaru’s service info for your engine. Different variants can specify different pressures, and matching the spec prevents overheating or undue system stress.
• How often should the cap be replaced?
  Have it inspected or pressure-tested annually and whenever coolant is serviced. Many owners replace the cap preventatively every few years, especially on older vehicles, as the rubber seal and spring age with heat cycles.