Knocking noise

Hi all, First time posting. 2008 Prius with 227,627 miles. Meticously maintained. Recently noticed car is making an unusual noise. Link to video here >>

This was recorded with car in park, in ready mode, emergency brake applied. Note the hiss, then knock knock knock... pause, repeat. Same sounds occur when car is turned off also. The hiss is normal, but doesn't generally repeat like it is. I've never heard the knocking noise before now. Any ideas what this is?

 

Was afraid of that.

 

Another video, a little more audible.

I strongly suspect the hiss is related to the brake accumulator, as mentioned above. The knocking is something of a mystery but I can't believe it isnt related. Curious if anyone else has experienced anything similar? Also, for anyone who has had to replace the accumulator, what was your ballpark cost? I'm in Northern California.

 

I'm disappointed I didn't get more replies on this. Not sure how to approach this issue, particularly with dealer service closing for Christmas. What I described as a hiss is more accurately described as whirring. It certainly falls within what people are describing as accumulator failure. The knocking noise which accompanies the whirring is concerning as I've never heard it before and don't find anyone else reporting that symptom. Do I just go to service and pay the $150 to disgnose it? Do I keep driving and hold my breath? Do I bite the bullet and trade it in for a newer model with fewer miles? I love my prius but can't even get a sense for how much this will cost to repair, but my hunch is it is expensive. Any feedback you can provide would be appreciated. I am a disabled woman who travels constantly and at some distance for medical purposes and cannot be without my prius.

 

Ed, thanks for this feedback. I love, love, love this Prius but my concern is as you stated... it seems to be an expensive repair and on a vehicle with so many miles. I feel like I've jumped the shark and now throwing good money (which i don't have) after bad. Do you happen to have a sense for whether I am safe to drive the car short term or am I at risk of a breakdown? Regarding the CAT... I was actually hit twice this year, two different locations in Sacramento. I carry full coverage but am out $1,000 in deductibles. The total cost was $3,800 each. Infuriating.

 

What is an EGR? I've been looking online mostly at 2013 - 2016 years with <110k miles. Would love a Prius V but my sense is repairs are even more than regular Prius. Do you agree?

 

Late June got hit in front of a friend's home in Citrus Heights. November 4th got hit again in front of a different friend's home in a nice, upscale neighborhood in Rancho Cordova. Both are eastern Sacramento suburbs. Police there said CAT thefts there are twice what they were last year. I've heard Davis is pretty bad too.

 

Dave Cook, thank you! That was informative and very helpful since I've been strongly thinking about doubling down with another Prius. It has been my favorite of the six cars I've owned in my lifetime. But expensive! I bought my 2008 in 2014 with 120k and have put 107k on it in the 7 years of ownership. Repairs and maintenance (not including the 2 stolen catalytic converters or the current issue) have run nearly $8,000 -- although it has been suggested the dealer may have taken advantage of me on at least one repair issue. But still, expensive. I think one block for me is having gotten so used to 40-50mpg in the Prius, it would be hard to go back to a regular car getting 28-35mpg. Plus, my Prius is comfortable. I've had 4 hip surgeries and no other vehicle is as easy to get in and out of. But you have me reconsidering and will seriously take this under advisement. Thank you!!

 

Dave Cook, you might appreciate this detailed breakdown of maintenance on my 2008 Prius. Yes, a commitment for sure. In so many ways the car is a real pleasure and a great fit for my unusual lifestyle (roaming medical patient, part-time Uber driver, Prius camper). The car is so functional and I still get so many compliments on it. It has begun to show a bit of wear and tear in the past year with some broken plastic creatively recovered in faux leather, broken center lid remedied with magnets, and recently, the rear hatch panel came loose which I intend to fix with glue. Of course, my trade-in value is now minimal which is heartbreaking. I reached out to my rep at Toyota service to ask about the brake accumulator and thought we might be able to do it for around $1,800, which I would have done... but she never called me back and I'm hearing in this group it is likely around $3,000, which I can't justify. And in the meantime, I'm not sure whether I am safe to drive. Do you have any wisdom on that issue? So far the car drives fine and no unusual noises or issues beyond the whirring and knocking.

 

Mr. Guy Mann, thank you!! That was very informative and I appreciate you taking time to explain. Do you have any idea what the knocking is about? I understand the pump trying to pressurize but the knocking is curious.

 

Dave Cook, you are correct that I do not (yet) have warning lights. My service rep (who knows me for years now) seemed reluctant to quote me on repairs when I don't have a warning or codes, only a noise. They don't seem keen on diagnosing.via video, even though I'm presently 150 miles from home. My point to them was that by the time the warning light comes I'm likely to have damaged the brakes and I'm big on doing repairs before major damage occurs -- a mindset that probably led me to do a few repairs a bit ahead of when they actually needed it. But yes, so far no warning or error codes, just the whirring and knocking.

I found the accumulator part advertised online by other local Toyota dealers at about $1,200, which tells me the part costs them about $600. So I was hoping $1,800 was realistic (factoring in my long term customer discount and the fact they just made $7600 on my two new catalytic converters) and I'd pay that -- and then probably be worrying about the hybrid battery until the next major repair.

To your question about the hybrid battery... yes, I'm still on the original. I think my saving grace is that my Prius is driven almost daily with only occasional breaks of a week or at longest two, when I'm physically unable to drive. I suspect this regular usage has helped keep the hybrid battery healthy to this point.

Given my love for the Prius vs. Ed's comment above suggesting I resist buying another Prius, I took a harder look at my numbers and did more research late last night. I found quite a bit of info indicating the 2013-3015 MY prius is one of the best cars around.

Also, my overall expense on the car doesn't seem so out of line when I look at the whole picture. The $8,000 repairs and maintenance sounds harsh until I factored it in with everything else. When I bought my 2008 I paid an extra $2,000 for an extended warranty, which was a waste as I never needed it and would not do it again. So I did not include that expense in my total. But I added up everything else and subtracted my anticipated trade-in value to arrive at a total of $22,518, which at 6.5 years of ownership comes out to approx $3,464 per year or $288.70 per month.


I'm not sure whether it is fair to subtract gas savings from that but it was interesting to do the math on 105,500 miles driven at 44mpg vs 35mpg I might have gotten with another vehicle, which at $4 avg per gallon in CA, is a savings of about $4,500 over 6.5 years. If I do subtract that it brings the total down to an avg of $231.32 per month over the 6.5 years of ownership. Looking at it this way, it doesn't seem like such a terrible deal. Am I wrong?

 

A quick update for anyone following this. I was able to have a conversation with a service advisor and an actual service technician at my regular servicing dealer back in Sacramento this morning. The technician wasn't at all opposed to watching my video and discussing with me. Confirmed it is the brake actuator / accumulator. Discussed my concerns re: fixing vs. trading in. Given my long and detailed history with this vehicle, which is otherwise in great shape, there seems to be a willingness to work with me to try and pursue a repair, but that's a little preliminary yet. The technician told me to have the advisor price out a CSP and a TSB (not sure what those are but presuming it is code for the actuator and accumulator). Estimated approx. six hours of labor. I haven't heard back yet about the pricing but I am hoping this means the advisor is looking into all possible discounts before calling me. Stay tuned...