Strange Noise From Rx400

[Robl45]

My wifes Rx400 has been making a strange noise. I especially hear it when waiting at the Drive Thru of Mcdonalds. It sounds exactly like when the windshield wipers are going but their is no water on the windows. I thought the back wiper was on by accident or something. But its definately not the wipers. I have it happen when driving and also just sitting waiting with engine off. Anyone have any idea what it could be?

[lenore]

could be the brake actuator...mine does the same, I am going to have my system flushed at the toyota dealership....mine only does it while the brake pedal is pressed...if this is when you hear the noise than it may be the same. Otherwise I would suspect something like a cooling pump. May be the inverter cooling pump....it is electric...mine failed last year...

[katzjamr]

remember also there is the noise that sounds like low level vibration, vacuum, buzzing that it think is the fuel system purging built up vapors, sorry for the non technical words, you hear it at shut down in the garage when its quiet, and i think it happens randomly while the engine is on.