2003 Infiniti G35--Loud fan, warranty nearing expiration

I have two questions regarding my 2003 Infiniti G35 Sedan:

-When the weather is hot, the air blowing through the fan sounds unusually loud, is this just lower air density or could there be blockage or something with a fan (I haven’t seen any in the radiator).

-I’m close to the warranty expiration ($100 deductible), is there a checklist of things to go through to see if there may be a failure (this car has been remarkably reliable).