Parts for your 2011 Mitsubishi Lancer-Thermostat

2011 Mitsubishi Lancer Thermostat — Purpose, Replacement and Servicing

Technical sources confirm the 2011 Mitsubishi Lancer uses a conventional engine coolant thermostat. The Mitsubishi Lancer 2007–2013 Workshop Manual (Cooling System section for 4B11/4B12/4B11T engines) details the thermostat’s operation and location, and the Mitsubishi ASA parts catalogue lists a factory thermostat and housing for these engines. Australian and New Zealand parts catalogues from brands like Tridon and Gates also list direct-fit thermostats for the 2011 Lancer, typically with an opening temperature near 82°C. So yes, the thermostat is absolutely relevant on this model.

The thermostat’s job is simple but crucial: it helps the Lancer warm up quickly and then holds the engine at a steady operating temperature. When cold, it stays shut to keep coolant in the engine for a faster warm-up. As temperature climbs, it opens to let coolant flow through the radiator, preventing overheating. That stable temperature keeps fuel economy tidy, emissions in check, and the cabin heater nice and toasty on a chilly morning.

On the 4B11/4B12 petrol engines (and the 4B11T in Ralliart/Evo), the thermostat sits in a housing on the engine side of the lower radiator hose, near the water pump, typically under the intake side of the engine. It’s a straightforward bit of kit, but because it lives a hard life, it can stick open (slow warm-up, poor heater) or stick closed (overheating).

There’s no strict replacement interval in the factory schedule, but it’s smart to replace the thermostat whenever there are temperature control symptoms, during a major cooling system service, or preventatively on higher-kilometre cars. Use the correct temperature spec, fit a new O-ring or gasket every time, and never force the housing bolts—warped surfaces or over-tightening will cause leaks.

• Common signs it’s due: running cool on the motorway, weak heater, temp gauge creeping in traffic, coolant pushed into the overflow, or fault codes for coolant temperature.
• Handy tips for the job: start with a cold engine, catch and dispose of old coolant responsibly, clean mating surfaces, lightly lubricate the new O-ring, and refill with Mitsubishi-approved long-life coolant at the correct mix.
• Bleeding: fill slowly, set the heater to hot, run the engine at fast idle, squeeze the upper hose to purge air, top up as needed, then recheck the level after a proper drive and cool-down.

While the bonnet’s up, it also pays to inspect the radiator cap, hoses, and water pump for leaks or ageing. Keeping the thermostat and cooling system in top nick helps the Lancer run efficiently and reliably, summer or winter.

FAQs

Where is the thermostat on a 2011 Mitsubishi Lancer?
It’s housed on the engine side of the lower radiator hose, near the water pump. On 4B11/4B12 engines it’s under the intake side