Fan running extremely loud

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If your Cruze sounds like it’s trying to take off every time it warms up, that fan is likely stuck on high speed. Since you’ve already replaced the thermostat and temp sensor, the next suspects are the fan control module or a signal issue from the engine control module (ECM). The fan is designed to go full blast if the ECM isn’t getting reliable temperature data—or if it thinks the engine is hotter than it really is. A failing coolant temp sensor circuit, poor ground, or even a bad radiator fan relay can cause this. Also, make sure the A/C isn’t stuck on, since that can trigger high fan speed too. It’s good news that it’s not overheating, but that fan shouldn’t be running like it’s cooling a jet engine. A scan tool that reads live temp data and fan command status can help pinpoint what’s telling it to go full tilt. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.