I have a 2007 Prius w/78K miles. This afternoon I had something happen that I don't recall happening before, and I am wondering if it's just something I've missed that is normal -- or if it is a sign of impending trouble. I'd driven about 30 minutes at speeds ranging up to about 45 mph; ambient temperature was about 70 degrees. I pulled into my garage and spent a few minutes listening to something interesting on the radio without shutting down the engine. I noticed a rhythmic noise or vibration from under the hood that I didn't recognize. It would occur for 10-15 seconds, then stop for about the same period of time, then start over. This kept up for three or four minutes, and I decided to pop the hood to see what I could find out. The noise seemed to be the radiator fan cycling on and off -- I say this because I put my hand on the top of the fan and felt it vibrating in synch with what I'd been hearing from inside the car. I don't remember ever hearing this; perhaps I just wasn't listening. During a point when the fan was running, I turned off the car and the engine stopped. This seemed odd to me -- I've owned other Toyotas with similar electric fans and those fans would stay on after I turned off the ignition if the engine needed to be cooled. Do I need to start worrying, or am I OK?
Was the air conditioning turned on? When the AC compressor runs, at least one radiator fan will also run. When you make the car IG-OFF then the AC system will shut down. If the engine required cooling, the radiator fan would not turn on and off at 15 second intervals.
It's better you take the air conditioning to repair are else you will face the problem with the coolant. Your battery loose its performance.
