Parts for your 2016 Subaru Legacy-Radiator cap

2016 Subaru Legacy radiator cap — purpose, fitment and service tips

Based on Subaru’s technical literature, the 2016 Subaru Legacy (BN/BS, known as Liberty in some markets) is fitted with a conventional radiator cap on the radiator neck, working with an overflow bottle. This is stated in the Subaru Service Manual for 2015–2017 Legacy/Outback (Cooling System – Radiator Cap) and reinforced by the 2016 Owner’s Manual cautions about removing the radiator cap only when cool. Major parts catalogues from recognised suppliers also list a pressure radiator cap for this model, confirming it’s used on the vehicle.

The radiator cap on the 2016 Legacy does more than just seal the top of the radiator. It’s a pressure regulator, typically rated around 1.1 bar (as specified by Subaru for this platform). By keeping the system under pressure, it raises the coolant’s boiling point so the engine can run at proper temperature without boiling over on hot days or long climbs. The cap also has a vacuum valve that lets coolant return from the overflow bottle as the system cools, keeping air out and the level spot on.

As part of regular servicing, the cap deserves a look under the bonnet. A tired or incorrect cap can cause slow coolant loss, overheating, or hose collapse. Check the rubber seals for cracks, the spring for stiffness, and the seat for corrosion. If there’s any doubt, or if a pressure test shows it can’t hold the spec, replace it with a quality cap that matches Subaru’s rating. Sticking with the proper pressure cap matters on these cars—too low and it may boil early, too high and it can stress hoses and the radiator.

Replacement is straightforward but only do it stone cold. Twist off the old cap carefully, wipe the neck clean, and inspect the sealing surface. Fit the new cap squarely and ensure the overflow hose is secure and clear. While you’re there, check coolant level in the overflow bottle and top up with the correct Subaru long-life coolant mix used for this generation. Many owners opt to replace the cap proactively every few years or around major cooling system work, as it’s a low-cost part that protects pricier components.

• Only remove the cap when the engine is cold.
• Use the correct pressure rating specified by Subaru for the 2016 Legacy/Liberty.
• Test the cap during cooling-system pressure checks, replace if weak, leaking, or corroded.

Popular questions about 2016 Subaru Legacy radiator caps

Where is the radiator cap on a 2016 Subaru Legacy?
It’s on the top of the radiator under the bonnet, towards the front of the engine bay. Open it only when the engine is completely cool to avoid scalding coolant or steam.

What pressure rating cap should be used?
Subaru specifies a pressure cap around 1.1 bar (about 108 kPa) for this model. Always match the vehicle’s spec on the cap label or the service manual—using the wrong rating can lead to overheating or undue system stress.

How often should the radiator cap be replaced?
Inspect it at every service. Replace it if the seals are perished, the spring feels weak, it fails a pressure test, or as a preventative measure every few years, especially if you’re doing other cooling-system work.