I just bought a Prius and it makes a cycling (same sound) about every ten seconds at high speed (about 60mph). It’s very quiet. It sounds kind of cycle, hum, whir. I never hear it otherwise and it comes at goes. I have thought it could be a wheel bearing just from what I’ve read. It’s just so quiet and not consistent. If it were a bearing, what are the consequences of not replacing? Any other ideas? Thanks so much.
If it's a wheel bearing that little quiet noise should start getting progressively louder and it should not take a really long time and it's really kind of strange that it's happening at like 60 miles an hour we're sure it's not any kind of water pumping or pump running or the break actuator and/or accumulator pump running excessively? And of course I'm assuming you have no dash lights no codes no nothing?.
Sounds like the brake pump. Does it do it while your idling? "If" it's a wheel bearing, and it locks up, you have problems! A wheel bearing would not do what you are discribing.
It could be anything. I have no clue, but it’s only happening at freeway speed and doesn’t always happen. No dash lights and no codes when I took it to a mechanic a month ago. It does not do it while idling. Only at freeway speeds. Most of the time, but sometimes it stops. It’s very soft and if you have music on you can’t hear it. A pump makes a lot of sense. Which pump do we think it could be?
Brake pump. You have a coolant pump for the engine, one for the inverter, then the a/c. Perhaps a loose hose?
I've never heard a story where the brake pump only runs repetitively at highway speeds though. Weird.
