Should my lower radiator hose be colder than the upper radiator hose?

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. Yes, it’s normal for the lower radiator hose to be cooler than the upper radiator hose in your 323i. The upper hose carries hot coolant from the engine to the radiator, and the lower hose carries cooled coolant back to the engine. This difference shows that your radiator is effectively cooling the fluid. However, if the lower hose is significantly colder or stays cold after the engine warms up, it could point to issues like trapped air in the system, a partially blocked radiator, or a malfunctioning thermostat. Double-check that you’ve bled the cooling system properly to eliminate air pockets, which can hinder proper circulation. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!