2012 Prius v Groaning Noise

We bought our Prius V on October 31, 2011 and only had it three weeks before hearing the groaning noise. Sounded like an old clunker. We also had excessive brake dust at the same time and though that was the problem. They cleaned the dust and it still persisted. We had it taken apart again and cleaned again and still had the noise. We then had the rear brakes replaced and still hear the same noise. We then had the entire rear system taken apart and we still hear the noise. We were assured it was not a safely issue. It used to happen only in the beginning of our journey, but now it is almost all the time. Very loud and frustrating.

 

I've had my Prius v since early December and have also heard this "groaning" noise. It's only when I start to accelerate and usually disappears within a few seconds. Now here's where my problem is different from almost everyone else...I live in an area where there is a lot less moisture in the air. Calgary is a high elevation town and the climate is quite arid and almost always below freezing in the winter. So my problem probably isn't caused by moisture. I was planning to take it to the dealer today but they're closed Sundays?!?! Anyway I'll be taking it next Saturday to see what they think. I'll update to let everyone know what they think at my dealership.
By the way, to me it sounds like a dry bushing so I'm not too worried...yet.

 

Well we experienced what I believe was the first groan out of the v3. Temp was in the mid 20sF and snowing with 1300 miles on the odometer. To me it sounded like breaks hanging up or the emergency break not completely released. It was startling. It shouldn't have been oxidation being the car was parked for an hour while we had dinner. I'll report back on our dealer too. W

 

I have a 2012 Prius V Five, live in eastern Oregon where it has been in the 20's and have not noticed this problem.

 

I did too encounter noise once back in February. Car was park in the garage for hour or so after driving in heavy rain. Noise was gone after pumping brakes a few times.
I heard consistently the same noise on Corolla after replacing pads and hear it after washing the other car.
There is nothing to worry about, at least for me. If you need to troubleshoot mechanical side of the noise, take a lawn blower and "dry" brake components before parking the car. If noise is still there, I would set and release parking brake a couple of time to see if parking brake release mechanism needs its time
I have filled outPriusV quality survey other day and put the subject down on issues list. Just one, for the team …

 

Very interesting .... I have a 2011 Prius and when I hand wash the car, the brake discs oxidate (rust) a little. This causes a scraping or maybe groaning noise that goes away after a block or so.

 

My first post - hope it works. My Prius V3 has a noise in the passenger rear that is random, usually in the AM, and the noise is not continuous and goes with the speed of the car. Pohanka in Salisbury MD (can I say that?) did a check of items while I waited 2 hours. No Trouble found. I finally caught it on a video and took the DVD to them. They kept it for several days, never heard the car make my noise. They tore down the brakes and found some evidence of unusual rubbing and dressed the area. They also broke down the drivers side to be sure. A week later the noise happened - rather loud. I keep the car in a garage, so why should moist mornings have the most occurrences? Brakes were not wet the day before.

I know it is not a safety issue, but it is annoying to have OLD technology blemish a fine car. My suspicion is a bad anti-rattle spring on the rotor pads. I caught it today and applying the brake somewhat firmly stopped the noise.

My dealer says the issue has been raised to the Toyota engineering team and the dealer awaits their instructions.

The nature of my sound is not a low groan. It is closer to an owl hooting - A mid-frequency tone that sounds like a resonance to it. As I said there is definitely a relation to speed as the tone appears momentarily at each tire rotation.

 

My wife and I have been noticing the "groan" as well, and it is only when the car has been sitting still overnight. We only purchased it in the beginning of December, but have noticed it in multiple types of weather. I live in a humid area but have had it up to Baltimore when it was below 20 degrees as well as in New Orleans and Orlando where the lows were in the 60s.
The noise does go away after the first half mile of going out of my neighborhood, but it is definitely an annoyance.

Has anyone been able to get a definitive answer from Toyota as to the issue or even a fix yet?

 

I called the Torrance CA Toyota center 800-331-4331 and they said they do not have a record of any activity. I got a case number assigned. I encourage all on this forum to call them. Unless people who have been ignored by the dealer or who are still annoyed at OLD TECHNOLOGY tarnishing an otherwise good car call we will get nowhere.

My dealer's shop foreman said the matter was in the hands of higher ups in toyota and until the engineers find a solution they cannot do any more. They were very good at tearing down the brakes, thought they saw some marks and dressed and lubed everything, but something is still wrong. See my post just above this one.

I just talked to the shop forman again and he said it is at the district level. I still would not hurt to tell Torrance folks

 

Our v 3, which we purchased Nov. 2011, just started exhibiting the groaning noise 1 or 2 weeks ago. It only happens after the car has been in the garage all night. When backing out, and applying the brakes, we hear the groaning. This continues everytime we apply the breaks for about 2 or 3 blocks, then it goes away. It's been pretty cold and wet here in Northern California lately, add that with other people's anecdotes, it seems those are two factors that contribute to this.

We just went for our 5000 mile service. The dude helping us just chalked it off to the "regenerative braking system." I figured it was more than likely BS. He said it happens on every Prius. Even so, I'm not terribly worried about it right now, but if it continue to happen when the weather dries and warms up, I'll definitely be bugging the Toyota service department again.

 

I found the reason when installing rear mud flaps after the dealer said it was at the regional level to tell him what to do. There is a tight spot when turning the rotor by the lugs that is not felt when the tire is on. The leverage and mass of the tire mask it. There is no play in the calipers but I nudged it to minimum hard spot and noise is diminished. The LR has equal drag all the way around and no noise. I am getting 40MPG so am surprised that there is drag. There is no pulsing when braking so you can imagine the precision that must be maintained to get rid of this noise.

Why can't Toyota recognize a rotor that is not true or that has thickness variations? I suspect that with wear on the rotor it COULD go away. But if the calipers stay tight to the rotor - as opposed to older Chrysler or Toyota rotors I have dealt with - the noise will continue. Give me a flat plate, precision blocks and a micrometer on a stand and I could diagnose further. But in any case, what good are the anti-rattle springs or have they been eliminated?

 

Time for an update of my experience with the groaning problem. I commented quite awhile back that I was having the problem consistently on chilly/damp days. Well, the weather here in eastern Washington is still unseasonably cold and damp BUT I no longer am experiencing the groaning noise. The only thing that has changed, and there has to be a connection, is that I changed wheels about 2 weeks ago. I took off my winter wheel setup, Blizzaks on the OEM Toyota 16" alloy wheels, and bolted on a setup of Michelin Energy Saver tires mounted on American Racing chrome plated alloy wheels. I had consistently had the groaning noise all the way up until the time I swapped wheels. I haven't experienced it since even though the weather is still cold and damp. I'm happy for now but I wouldn't bet against the noise coming back next winter when I put those wheels back on. The wheel change really shouldn't have anything to do with the noise UNLESS something tight got loosened up in the change-over process. That would be my guess.

 

Maybe whoever put on the snow tires over tightened the lug nuts. Over or uneven tightening could warp the rotors on any vehicle. This is a really common problem as many tire shop employees don't want to spend the extra time and effort digging out the torque wrench unless you ask.

 

Yes, that is very true but that doesn't explain why the groaning noise ONLY occured when it was cold and damp. Shouldn't it have occured under any condition under that scenario? Also a number of other owners have mentioned taking their v's in to the dealer and having the wheels pulled and inspections done. You would think those wheels were reinstalled correctly. Les Schwab did the changeover this time since the chrome wheels were bought from them. After about 100 miles of driving I personally did the retorque since I do have a torque wrench. Still a mystery I guess.

 

Hmmm, not sure what the groaning sounds like, but I know when I run the Blizzaks, my car makes a noise it doesn't make when my Energy Savers are on. I say it sounds a little bit like when a roller coaster goes, but not nearly as loud. I chalk it up to the tires, because it's not there any other time.

 

No, this is an entirely different thing than tire noise, believe me. Read through the entire thread and you will understand. It's very possible that I am the only victim that is even running Blizzaks. And I had Blizzaks on my 2 previous Prii and never experienced the "groan".

 

Sounds to me like rust build-up on the brake discs. The main time I'll notice this (on our reg. Prius) is if it's been sitting after a car wash, say overnight.

 

We live in Austin Texas and are getting the noise (groaning in reverse) in warm weather.

Local dealer had it for three hours last week and came away empty handed.

 

In an earlier life I worked for a brake manufacturer. While most aspects of an engineered brake system are pretty predictable, brake pads are tricky. They vary in aggressiveness, wear rate, dust generation and "creep groan" among other things.
Some compounds tend to leave deposits on the disc surface (particularly when used gently, and when the disc surface is new and relatively rough) that can lead to steering shimmy and pedal pulsing in conventional brake systems. Often a strong application of the brakes will wear this off of the surface, but it can return again later.
Temperature and humidity are factors in the behavior of a given compound.
Damping shims (and, yes, sometimes high temperature grease on the back of the backing plate) can cure squeals and groans, etc.
Why does the sound pulsate? Because the pad is probably leaving a fine patch of lining material or rust wherever it stopped for a while.
Why just Prius v's? I suspect you'll find that Toyota used a different pad compound (or disc size or caliper) to address the extra vehicle weight or to improve the pedal feel somehow.
My advice to the afflicted: be patient. Brakes are probably the most common source of customer complaints on any given new car and a fix from Toyota could take a while to formulate and implement. The problem could also disappear with miles. it doesn't appear to affect safety or fuel economy.
Keep the dealer informed, but be patient.

- Chris