Grinding noise for 20-30s at cold startup...

Sorry, Quicktime does not understand ".MTS" file format.

Bob Wilson

 

I can't watch your video here, but a quick check to start zeroing in on what your sound could be....

If you just turn the key to ON (not to the START position, no need for the car to be READY), then pump the brake pedal a bunch of times, you should be able to start the brake accumulator pump. It makes a kind of buzz/whirr for a dozen or two seconds, then stops with a toink. Sometimes it will do this a few times in a row (whirr-toink whirr-toink whirr-toink). You can listen to that any time you want (just by pumping the brakes until the pump kicks in) and see whether that is the sound you are hearing.

If so, don't worry. That's just what it sounds like.

-Chap

 

Wow..

Well it isn't the brake noise, that sounds normal. Car starts and sounds normal.

Then after about 10 seconds it starts making 1s pulses of what sounds like when you engage a starter into a moving flywheel... Or a tin can dragged along a rough concrete.

It might be coming from the coolant pump.

It does sound louder under the inverter.. Did you place your hand on inverter metal to feel for this noise? It could possibly be something like air pockets in the coolant getting sucked in by the pump circulation and vibrating the metal of the inverter case... Like the sound a pool pump might make sucking in air...

But really I guess something in transaxle, but what would make intermittent noise like that... Other than air pockets... But that is loud..

Possibly stick your head under the car and see if you can hear it coming from the valve on the catalytic converter on the exhaust.. possibly that might be making a scraping noise??? long shot I guess..

If you start car and immediately start driving in reverse does it make the noise?

When you start it like this, if you step on gas and increase RPM does it change the noise..

If it is the transaxle and MG1 or the chain, then you should be able to step on brake with left foot, shift into D and step on the gas while holding in the brake, and see if that impacts the noise at all. That will engage the moving parts in transaxle under load..

If you put car to ready does the ICE ever shut off?

Upload that thing to a YouTube account, it can convert your video.

 

Wat u mean noise happens without turning on ignition.

If the car doesn't say READY then there is no high voltage and rules out that being an arc'ing noise.

What is running with key in ACC? some computers, the cabin fan, the capacitors for the brake system that have 12V on them. a 12V relay in the fuse box that is high speed clicking???

If you want any help diagnosing it, you need to be more specific about when it happens, and feel around in there for mechanical vibration. If it does it with key in but not READY, then it should be easy to diagnose.

 

put hands on relay see if you can feel one chattering.

ALl I can figure is that it is high voltage arcing inside inverter or one of the orange wires. Maybe some type of air bubble coolant noise, or pump making noise somehow. Maybe some exhaust noise or the cat exhaust diverter valve.. It sounds like it is the inverter aluminum vibrating.

If you put car in reverse, step on brake and give it some gas for a few seconds, the ICE will shut off in that first 30 seconds so you can hear it better (?)

 

Hey did you ever find out what was happening? I have a similar noise although not as bad as yours...

Here's my thread and my video:

When I press the Power On button, I hear a slight grind | Page 3 | PriusChat

 

that is really something. that just sounds electrical, or something rubbing metal. sounds loud over the inverter. are you getting any lights on the dash

 

Sounds like the brake pump and master cylinders. There is a strong motor that charges the accumulator. If you press the brake pedal, does the noise change?

Bob Wilson

 

That looks like the brake assembly to me. First, make sure there brake fluid level is OK. If not, top it off and hope for the best. But loss of brake fluid is not good either as one wonders 'where did it go?'

If filling the brake fluid doesn't solve the problem, it is likely to sooner or later be expensive, $1,000. Although one might get a used part from a salvage yard, the real risk is that any metal filings might have contaminated the brake lines. If so, at a minimum, everything gets flushed and there is still a risk of contaminated caliper and rear brake actuators.

Bob Wilson

 

Please recheck your brake fluid, my 2000 prius has the EXACT same sound, i checked the brakefluid and put a finger in the container, it is well between low and high. but there is only like 2 mm brakefluid in the container to the bottom. I have the same level as yours on the youtube video. i have refilled/topped up the brakefluid to max, and now it have a lot less rattle.
But since mine has been rattling for almost a year i think i have to bleed the actuator. i will do this as soon as possible at work.
Please read this article:

Brake Job: Toyota Prius: Brake and Front End

i am pretty convinced this is the problem, that the pump is getting air, the noise it makes fits this theory.
Here´s and arthicle on how to bleed the entire system:
C1256 low pressure accumulator- ABS beep | PriusChat
Sorry for the Bad english i live i Sweden and have been a Prius owner for 4 years and own a 2007 and a 2000

Regards Eg Egemarke

 

My 2003 prius is experiencing the same grinding noise that you posted. What did you find to be the problem? It just started for me a month ago. The Toyota garage and another mechanic have yet to diagnose it. Any help would be much appreciated.

Thanks
Katie

 

Yes. If that doesn't help then the brake actuator assembly probably will need to be replaced.

 

Any update on your situation? My 2002 model is making the exact same noise at startup, but there are no warning lights yet.