Parts for your 2013 Subaru Impreza-Radiator cap

2013 Subaru Impreza radiator cap — purpose, care and replacement

Based on Subaru’s own technical documentation, the 2013 Subaru Impreza (GP/GJ chassis, FB20 engine) is equipped with a pressurised radiator cap. The Subaru Service Manual for the GJ/GP model (Cooling section) specifies a pressure cap on the radiator filler neck, and the Subaru FAST parts catalogue lists a dedicated radiator cap for this model year. Aftermarket catalogues from major cap manufacturers also cross-reference a pressure cap for the 2013 Impreza, confirming that a radiator-cap is fitted and relevant to this vehicle.

The radiator cap on a 2013 Subaru Impreza isn’t just a lid, it’s a key part of the cooling system. It seals the system and maintains a set pressure so coolant can run hotter without boiling, which keeps the engine happy on Aussie and Kiwi roads—from city traffic to long open stretches. The cap also controls coolant flow to and from the overflow bottle as the engine heats and cools, keeping the system topped up without pulling air back in.

When it’s time for servicing, a tidy radiator cap check is well worth it. Under the bonnet, a tech will inspect the rubber seal, spring action and the neck it seals against. Any cracking, swelling, corrosion or a weak spring can let pressure drop, which can lead to overheating, coolant loss, or hoses collapsing as the engine cools.

Replacement is inexpensive insurance. Many workshops swap the cap whenever coolant is renewed, or sooner if there are symptoms like rising temperatures, hard upper hoses after shut-down, visible leaks at the neck, or the overflow bottle not behaving as usual. Always fit a quality cap with the correct pressure rating as specified for the FB20 engine—matching OE spec is the go.

Basic tips owners appreciate:

• Only check or remove the cap when the engine is stone cold—never when hot.
• Keep the sealing surfaces clean, wipe away crusty deposits that can compromise sealing.
• If chasing intermittent overheating or slow coolant loss, test the cap alongside thermostat and fans.
• Use the right coolant and bleed the system properly after any cooling work to avoid air pockets.

With the right cap in good nick, the Impreza’s cooling system holds pressure like it should, helping it rack up the kilometres reliably.

Does the 2013 Subaru Impreza have a radiator cap and where is it?

Yes. The 2013 Impreza uses a pressurised radiator cap mounted on the radiator filler neck (top tank). There’s also an overflow reservoir nearby, that bottle is not pressurised.

What are the signs the radiator cap needs replacing?

Look for dried coolant around the neck, a split or hardened seal, temperature creep in traffic, hoses that collapse as the engine cools, or the overflow bottle not returning coolant. If any of these show up, test or replace the cap.

What pressure rating cap should be used?

Use a cap that matches the factory specification for the FB20 engine in the 2013 Impreza. Check the owner’s manual, the under-bonnet label, or a trusted parts catalogue and stick with reputable brands.