Prius V 2012, 125K miles The car's developed a rumbling sound coming from what seems like the right front tire area. Some details: 1. It occurs at all speeds. 2. It's not a consistent rhythmic rumble (as in some part rubbing against another part). 3. The rumble is all the same volume. 4. It's chaotic -- in that I'll hear many short rumbles, silence for a few seconds, a single rumble, two rumbles in a row, sometimes three rubles, with no consistency. 5. I can feel the rumbles, a sort of low vibration. 6. It's not connected to anything on the road -- it's will happen on a smooth, newly paved asphalt road. My mechanic thinks it's the struts. I took many pictures (below). There's fluid covering the area on the inside of the right front tire as well as on a bracket below. (Sorry, I can't ID the parts; could be the strut, could be the brake.)
Struts could be bad but the leak should be small and localized to the strut. Bounce test them. A cv joint can splatter grease but that requires a torn boot. An easy to see diagnosis. However a bad cv joint can happen without a tear and could cause vibrations, usually far worse on turns. Both of the above are rare on a Prius with oem parts. A timing chain or pressure switch leak will dump oil everywhere on the right (passenger side). Tricker to see but common. It is would look like motor oil and not grease. A worn wheel bearing / hub assembly can make a humming noise and is relatively common. Most experienced mechanics can diagnose any of these. A trip to the dealer for a proper inspection might be worth $150 without risking changing good parts.
