Parts for your 2012 Subaru Forester-Radiator cap

2012 Subaru Forester radiator cap

Based on Subaru’s technical literature—the 2012 Forester Owner’s Manual (Cooling System section), the factory Service Manual (Cooling/CO), and OEM parts catalogues listing a pressure cap for 2012 Forester engines—the vehicle does use a radiator/pressure cap. On this model the cap is typically fitted to an engine‑mounted coolant reservoir (often called a header tank), not on the top of the radiator itself, which is why some owners don’t spot it under the bonnet at first glance.

This cap does more than just seal the system. It holds a set pressure so the coolant can run hotter without boiling, helping the Forester keep its cool on long Kiwi or Aussie drives, steep climbs, and summer traffic. When pressure exceeds the cap’s rating, it lets excess coolant move to the overflow bottle, then draws it back as things cool. Most 2012 Forester trims run a cap around 108 kPa (1.1 bar), some turbo variants may specify a higher value. Always match the rating printed on the original cap or confirm by VIN with the parts catalogue.

As part of servicing, a quick cap check is cheap insurance. Under normal use, it’s smart to inspect it at least every 12 months or 20,000 km and replace it whenever the rubber seal is cracked, the spring feels weak, or there’s staining that hints at seepage. Many techs also swap the cap whenever major cooling work is done—radiator, water pump, or coolant changes—just to keep everything tidy and reliable.

• What to look for: perished or flattened seals, rust on the neck or cap seat, crusty deposits, or hoses going rock‑hard quickly after start (over‑pressurising) or staying squashy when hot (under‑pressurising).
• Good practice: only remove the cap when stone cold, open to the first detent to vent, then remove. Wipe the neck clean, check the spring action, and confirm the pressure rating. Use quality OEM‑spec caps—cheapies can cause chasing-your-tail overheating issues.
• After refilling coolant: fill via the header tank, run the engine with the heater on hot to purge air, and top up as needed. Air pockets can mimic thermostat or head‑gasket troubles.

Treating the 2012 Forester’s radiator cap as a small but critical pressure valve keeps the cooling system stable, helps avoid boil‑over, and protects bigger‑ticket parts down the line.

Popular questions about 2012 Subaru Forester radiator caps

Does the 2012 Forester have a cap on the radiator itself?
It usually doesn’t. Subaru places the pressure cap on a raised engine‑side header tank so the highest point in the system is where you fill and bleed. The radiator core is typically cap‑less and fed by hoses from that tank.

What pressure rating should the cap be?
Most non‑turbo 2012 Foresters use a 108 kPa (1.1 bar) cap. Some turbo models may specify a higher rating. Check the marking on your existing cap or confirm with the vehicle’s VIN to be sure you’ve got the right one.

How often should the cap be replaced?
Inspect it yearly and replace at the first sign of seal wear, corrosion, or pressure loss. As a rule of thumb, many workshops replace the cap every few years or during major cooling service to prevent sneaky overheating or coolant loss.