Q: 2006 Commander keeps running hot. The radiator has been replaced, what could be the problem?

There are a number of other things that may cause the motor to run hot such as a stuck thermostat or faulty cooling fans that may not be coming on at the correct intervals or speeds. The thermostat regulates the flow of the coolant in your car’s engine and controls when the coolant flows in and out of the motor from the radiator by opening and closing at specific temperatures. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. When the thermostat is stuck open it can cause the coolant to circulate constantly resulting in the motor never reaching the correct operating temperature.

A faulty cooling fan that is not coming on at the correct times is usually caused by a faulty cooling fan relay. The coolant fan relay helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this relay is not working properly, this can cause the fans to come on intermittently, stay on all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. I would suggest having an expert from Your Mechanic come to your location to diagnose and inspect your vehicle.