smartcarofamerica.com/threads/2008-smart-fortwo-engine-overheating.45977/

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Forum thread: 2008 Smart fortwo engine overheating. | Smart Car of America Forum

smartcarofamerica.com/threads/2008-smart-fortwo-engine-overheating.45977/ · p. 1 · Applies to: 451

Source: smartcarofamerica.com Topic: engine overheating, coolant overflow Models discussed: 451 Solution status: unclear

Problem: 2008 Smart Fortwo engine overheating with coolant overflowing from the antifreeze reservoir and red temperature warning light activation during driving, despite bleeding air from cooling system and installing new thermostat and cooling temperature sensor.

Solution: Multiple diagnostic approaches were suggested but never confirmed as resolved: (1) Ensure thermostat is installed correctly and not stuck closed; (2) Bleed air from cooling system by running engine at elevated RPM on an incline with heater set to maximum to open all heating system valves, allowing the radiator and reservoir to sit above the engine; (3) Check for blown head gasket by inspecting oil dipstick for coolant contamination and using a Block Chek combustion gas detector in coolant system; (4) Replace reservoir cap; (5) Verify correct 50/50 coolant mixture. The thread suggests potential defective thermostat as a known issue with some BEHR units. unresolved

Key facts: - Vehicle exhibits red engine temperature warning light during driving with coolant overflowing from reservoir - User installed aftermarket thermostat from dealer and cooling temp sensor from Mitsubishi Mirage (sourced from eBay) that physically fits - Multiple bleeding attempts have not resolved the issue - Smart USA recommended bleeding air from cooling system as initial diagnosis - Possible causes discussed: trapped air in cooling system, backwards or stuck thermostat, blown head gasket, defective thermostat - Block Chek device recommended to test for combustion gases in cooling system - Running vehicle at high RPM on incline with heater maximized suggested to fully bleed system