Clogged Radiators. Learning to recognize blocked radiator symptoms is an important part of car maintenance because clogged radiator fins, cooling tubes or a clogged coolant hose can cause the engine to overheat and cause permanent and serious damage.
Engine Temperature: One of the most common and easily monitored symptoms of a blocked radiator are higher than normal temperatures when running. You should be monitoring for this every time you drive by paying attention to the dashboard temperature gauge. This gauge sitting even a little high over a long period of time can be one of the signs of a blocked radiator.
Coolant Colour: one of the less immediately noticeable, but still easily monitorable, signs of a blocked radiator is the coolant colour changing over time. When you get your car serviced or change the coolant yourself, you should take note of the coolant colour. When there is a problem with the radiator the coolant can change colour.
Leaking Coolant: one of the often-unrecognized blocked radiator signs is the leaked coolant on the ground underneath a car. This can often be passed off as condensation from the air-conditioning and missed, which can cause further internal damage to the radiator.