I noticed about a month ago everytime after my RX idles for a while I hear something come in like a fan then it turns off. Well today I noticed after sitting in traffic that my gauge for the temperature was going up, once I drove the needle came back down. My coolant level is good, could this be a leak?

 

sounds more like a problem with the fan not coming on. whether thats a temp sensor issue or the fan itself is something you will have to test.

 

Sounds like the cooling fan sensor.

There is an easy way on how test the radiator fan itself. Simply turn on the A/C to the coldest temperature, the cooling fan should come on immediately. If the fan fails to operate you have a bad cooling fan. If the fan turns on the cooling fan sensor is the culprit.

 

Thank you everyone I will have my husband check this out and let you all know what I find out.

 

can put a coolant pressure tester on it for leaks.
can remove coolant temp sensor connector and see if needle goes to full cold then ground that sensor and see if needle goes to full hot.