Electric water pump and thermostat failure (N55)
The N55's electric water pump, usually replaced together with the thermostat, is a known weak point; FCP Euro puts its typical life at 65,000 to 75,000 miles. It often fails with little warning, the engine drops into a reduced-power mode to protect itself, and driving on can overheat it.
How to check
Look for a water pump and thermostat replacement in the records, and treat an original pump on a car past about 70,000 miles as due. Check for coolant warnings in the history.
