A/C condensor fan noise...is this normal?

I have a 2007 Prius with 38000 miles. I have noticed noise coming from the engine compartment lately and attributed it to the A/C. Today I pulled the car out of the garage and left the car in Ready mode while I did some work in the garage and heard the noise again. After an investigation I found that the noise is coming from the right hand side radiator fan (as viewed from the driver's seat). I can hear the compressor come on quietly (confirmed by the absence or presence of a small vibration at the refrigerant connections to the compressor), followed in a few seconds by the passenger side fan which I believe is now very loud. The fan is louder than the ICE. The A/C runs and cools normally. I tried to attach a short video, but I can't seem to get that to upload to PriusChat.

I spun both fans by hand, and don't hear or feel anything unusual. I did notice that the left fan appears to turn more freely than the right fan. I did not ever see the left hand fan running, but that might be due to the ICE not being warm enough to require it. The outside air temperature at the time was 72 degrees F.

I think I need to replace the right hand fan, but I'd like to confirm that the noise is not normal before I spend the time and money to replace the fan.

 

I went back and did some more troubleshooting. I pulled and replaced the #2 and #3 fan relays, and both fans now come on at low speed when the A/C compressor is running. The relays appeared to be tight and clean and I could feel them turning on and off before I pulled them, so I'm not sure what I did to get the other fan running.

The right fan still makes a noise that sounds like a failing bearing, but the left fan runs almost silently as I would expect. The noise is not too bad at low speed, so I may just wait until something else goes that requires coolant replacement and do it all at once. The shop manual says you need to drain the coolant to remove the fan assembly, although I think I could get it out without disconnecting anything other than the overflow lines.

Thanks for the help.

 

I decided to go ahead and replace the fan motor so I could quit worrying about it. Toyota sells the parts individually, but the motor has an MSRP of over $200, and the best price I found online was $150. I found an aftermarket assembly that includes both fans, two motors, the shroud, and a new coolant overflow tank for $122 including a lifetime parts warranty. While I usually prefer genuine Toyota parts, this seemed to be the better solution given that the original Toyota fan motor lasted only 38,000 miles.

I was able to install the unit by removing only the radiator inlet hose. The Toyota shop manual tells you to drain the ICE and inverter cooling systems and remove most of the hoses, so I saved the time and trouble of doing that as well as avoiding the aggravation of getting the air out of two systems. I did have to bleed the ICE loop, but it was much easier that it would be had I completely drained the system.

The new fans are very quiet and appear to work fine. I'm going to check the radiator level after a couple of driving cycles to ensure that it is still full of coolant.

 

RockAuto.com

I got a 5% discount because I bought a bunch of stuff from them recently for another car. Amazon also had the exact part for a couple of dollars more.

 

I did check the air flow after installation and they are pulling air from front to back. Since I replaced the entire assembly, I didn't have to worry about getting the fans in wrong. The motors are counter-rotating, so it is possible to get reverse airflow if the fan blades were exchanged. If anyone suspects that the fans have been reversed, the left hand fan has five blades, and the right hand fan has seven blades. Any other combination of OEM parts would indicate a bad installation.