Grinding Noise from Dash

Starting this past winter, whenever the overnight temperature drops below 45 degrees, a loud grinding/whirring noise emanates from inside the middle of the dashboard of my 2006 Prius. The noise occurs in regular one second or so intervals, and appears to originate inside or behind the touchscreen and radio/CD player. The noise continues for about 15-20 seconds, and then goes away. The problem won't reoccur until the car cools overnight - i.e. the grinding noise won't reappear if I start the car up again when it's warm.

I recorded the sound this morning and have attached a sample WAV file here.
I had to upload it as a zip file because the upload facility on PriusChat apparently doesn't allow one to directly upload a wav file.

The noise sounded suspiciously like a faulty CD transport mechanism: that's what I concluded and that's what my Toyota dealer's service department concluded as well, though it didn't appear to affect the functionality of the unit. Last week the service department replaced the CD unit under my extended (7 year) warranty. Surprisingly, the sound is still there, if anything somewhat louder and more persistent. And the problem increases in intensity with a drop in temperature. Now, if the temperature drops below freezing, the grinding noise is near constant for up to 15 seconds or so, then reverts to the periodic grinding intervals for another 15-20 seconds before stopping entirely. What's particularly insidious about this problem is that it's so short-lived, making it very difficult and inconvenient for the service department (and myself) to diagnose. So I thought I'd submit this issue to the forum, to see if anyone else has encountered it.

Any advice/thoughts would be greatly appreciated.

Steve in Jersey

 

Good suggestions, Ron. I'll check out the heating system and suggest that (and brake actuator) to my service department.

 

Thanks. I'll try the approach you suggest, but frankly it doesn't sound like a fan. It sounds more like a gear or solenoid. If you ever get the chance to listen to my WAV file, or if there's another way I can provide you with an audio sample, let me know. I'd value your opinion if the noise is the same. But I'll try what you suggest. Thanks.

 

To BlazingStar -

After further investigation, I'm beginning to think that your suggestion is correct. We've been going through a frigidly cold spell here in New Jersey and that intermittent sound has become more of a continuous whirring noise which continues for about one minute before reverting to the intermittent noise. And it seems as if the noise is coming from directly behind the touch screen.
If I were to send you another sound sample, but in the form of an MP3, would this help with your computer sound problem? I would really love to get your direct feedback on whether this sound is the same as what you experienced.

 

Thank you very much. I believe/hope you have diagnosed my problem for me. I am under extended warranty and the service department claims they want to help me (asked me to call them on Saturday to arrange to leave car with them until they find problem). I will definitely alert them to this (actually copy your message and bring it with me). Thanks very much and I will let you know what happens.

 

Thanks. Just scheduled it for Tuesday (getting loaner car). I mentioned your experience and your offer for them to get in touch with your service department if they find it would be helpful. Hopefully not necessary.

 

I will certainly share the results. Funny, looks like we have two possible problem sources here. BlazingStar's problem apparently was due to a cooling fan behind the touchscreen. I will suggest both of these to Toyota service, but I'm sure they'll want to do their own investigation. Hey, I've got loaner car so they can take their time to find the source.

 

Funny you should ask. I was going to post a message here today
to let you know that there is still no meaningful outcome to speak of. It's been frustrating.
My north Jersey Toyota dealer, though cooperative, has been
wanting in execution. Basically the car is in their shop for an indefinite
period until they can confirm the sound for themselves.
Despite painstaking efforts on my part to document
the problem for them, how they would have to leave the car overnight
and then start it when ambient temperature is less than 40 degrees,
they claim they have yet to duplicate the sound. That's because the service techs didn't
follow my instructions to sit in the car and wait about 5 minutes when the
temperature goes REALLY low (below 30 degrees).
At this temperature, it takes 5 minutes for the sound to materialize.
Thankfully I made an MP3 recording of the sound, burned it
onto a CD, and stuck it in the Prius's CD Player. So they've at least been
forced to recognize that the sound actually does occur and is not normal. The service manager
says he'll personally try my recommended 'diagnostic procedure' tomorrow.
I extended your offer to have him get in touch with your Toyota service department,
but - no surprise - he insists on confirming the problem for himself rather than talk to anyone.
Also, I followed your advice and put my ear up against the touch screen when the grinding noise
was being emitted. It seemed like the noise was coming from DIRECTLY behind the screen - within
inches. So I'm near 100% certain that your diagnosis is accurate.
What is so frustrating is that -for a company so committed to advance technology - why
on Earth don't they have or consult with a database that has already documented this problem?

So right now I have a loaner car from them, and I don't intend to relinquish it until they have resolved
this to my satisfaction.

 

Funny you should ask. I was going to post a message here today
to let you know that there is still no meaningful outcome to speak of. It's been frustrating.
My north Jersey Toyota dealer, though cooperative, has been
wanting in execution. Basically the car is in their shop for an indefinite
period until they can confirm the sound for themselves.
Despite painstaking efforts on my part to document
the problem for them, how they would have to leave the car overnight
and then start it when ambient temperature is less than 40 degrees,
they claim they have yet to duplicate the sound. That's because the service techs didn't
follow my instructions to sit in the car and wait about 5 minutes when the
temperature goes REALLY low (below 30 degrees).
At this temperature, it takes 5 minutes for the sound to materialize.
Thankfully I made an MP3 recording of the sound, burned it
onto a CD, and stuck it in the Prius's CD Player. So they've at least been
forced to recognize that this sound is not normal. The service manager
says he'll personally try my recommended 'diagnostic procedure' tomorrow.
I extended your offer to have him get in touch with your Toyota service department,
but - no surprise - he insists on confirming the problem for himself rather than talk to anyone.
Also, I followed your advice and put my ear up against the touch screen when the grinding noise
was being emitted. It seemed like the noise was coming from DIRECTLY behind the screen - within
inches. So I'm near 100% certain that your diagnosis is accurate.
What is so frustrating is that -for a company so committed to advance technology - why
on Earth don't they have or consult with a database that has already documented this problem?

So right now I have a loaner car from them, and I don't intend to relinquish it until they have resolved
this to my satisfaction.

Read more: http://priuschat.com/threads/grinding-noise-from-dash.121095/#ixzz2JzpvWD1T​