Parts for your 2010 Mitsubishi Lancer-Radiator cap

2010 Mitsubishi Lancer radiator cap — what it does and how to look after it

Technical sources confirm the 2010 Mitsubishi Lancer is fitted with a radiator pressure cap. The Mitsubishi Motors Service Manual for Lancer CJ (Group 14A: Cooling) specifies cap inspection and a pressure rating around 108 kPa (1.1 bar), the Mitsubishi ASA parts catalogue lists an OEM cap (e.g., 1350A008) for 2007–2012 CJ models, and major application catalogues from Stant and Gates also list a 1.1 bar cap for the 2010 Lancer. Evolution X variants may use a different rating, so checking the cap label or VIN-specific parts data is smart.

On this Lancer, the radiator cap is a small, hard‑working safety valve. It seals and pressurises the cooling system so coolant boils at a higher temperature, keeping the engine happy on hot days and steep Kiwi and Aussie climbs. Inside the cap is a spring-loaded pressure valve that releases excess pressure into the overflow bottle, plus a vacuum valve that draws coolant back as the engine cools so hoses don’t collapse.

As part of regular servicing, the radiator cap deserves a quick once‑over. A tired cap can mimic bigger cooling problems. If it can’t hold pressure, the engine may run hotter, push coolant out, or fluctuate on the temp gauge. If the vacuum valve sticks, the upper hose may flatten after cool‑down. Any sweet coolant odour, crusty deposits around the neck, cracked rubber seal, or a wobbly spring are red flags.

Good practice for a 2010 Lancer is to:

• Test the cap annually with a cap tester, or replace it every 3–5 years/60–100,000 km.
• Use the correct pressure rating (typically 1.1 bar/108 kPa for non‑Evo models). If in doubt, match the OEM spec on the cap or parts catalogue.
• Only remove the cap when the engine is stone cold. Use a rag, press down, and turn slowly.
• After refitting, top the overflow bottle to the “FULL” mark, run the engine with the heater on hot, and check for bubbles or drops in level.
• Avoid mixing coolants, stick with the correct spec and replace the cap if contamination has swollen or perished the seal.

A quality, correctly rated cap is cheap insurance for the 2010 Lancer’s cooling system. It helps maintain stable temps, prevents boil‑over, and keeps the system bled and balanced between the radiator and overflow bottle.

Popular questions about 2010 Mitsubishi Lancer radiator caps

What pressure radiator cap does a 2010 Mitsubishi Lancer use?
Most non‑Evolution 2010 Lancer models use a 1.1 bar (about 108 kPa/16 psi) cap. Always check the label on the existing cap or confirm via the VIN in a parts catalogue. Evolution X variants may use a higher rating, so don’t assume—verify.

How often should the radiator cap be replaced on a 2010 Lancer?
Inspect it at every coolant service and test it annually, many owners replace the cap every 3–5 years or 60–100,000 km. If there are signs of leakage, a weak spring, a torn seal, or temperature swings, fit a new, correct‑rating cap straight away.

What are the symptoms of a failing radiator cap on this model?
Common clues include coolant loss into the overflow, a sweet smell under the bonnet, chalky deposits near the cap, hoses collapsing after cool‑down, and fluctuating temp readings. Any of these warrant testing or replacement before chasing bigger faults.