Wheel noise

[Sirua2014]

Hi I’m new to the hybrid world and have two noises coming from my e18 hybrid

1. when braking it sounds like brake pads are running extremely low like that metal on metal sound or rust on disk. just bought the car from rrg Toyota and just been serviced so should be working correctly.

2. when the car is running down hill in silence I can hear what sounds like a wheel bearing. Or is this part of the charging thing on the Battery with the car self charging. It’s like a low quiet duff duff duff you can hardly hear and gets faster as you do. To me sounds like a wheel bearing but thought I’d check

thanks for all responses in advance

[Beekeeper D]

Firstly, the hybrid system doesn’t make duff duff duff rhythmic noises. Tube train whine, yes a little, but speed dependant chugs, no. Sounds like something the dealer needs to take a look at. 

If the car hasn’t been used for a while, there may be a little brake roughness. Fix is simply to use the brakes hard enough, for long enough, once or twice, which shouldn’t be hard with the hills in most of Yorkshire! 
Obviously, nobody here can tell you whether that is all that is the matter. 
One hybrid driving skill is minimising the energy lost by using the friction brakes, braking gently to absorb the energy as regen. But in the extreme, with little mileage plus wetness, that can mean that the disc rotors can get rusty and wear the pads quickly. You should be able to see for yourself whether the discs are badly scored, but while sorting the other thing, discs and pads are something else you should ask to be checked, if the brake scratching hasn’t come right pretty quickly. I would have expected the service record to show their condition explicitly. 

[MagicBoy]

The hybrids do make some atypical noises, mainly mechanical things the the ICE engine would drown out in a normal car. There's a bit of whine from the motors and electrical noises when it's shunting power around the system.

For the duff duff duff - check the tyres first. Could be a stone stuck in the tread. 

[Beekeeper D]

Yes hybrids can run more quietly than petrol or diesel vehicles, which means you can notice things you otherwise might not! You will likely notice significant changes in tyre noise with different road surfaces. 
However, while driving the only noise the electrical systems themselves produce is the slight whine. 
You will notice some “mechanical” noises after you stop and the car progressively shuts down over a minute or two. Similarly, powering on is accompanied by the odd unfamiliar clunk and whirring.

[Gerg]

On 9/20/2020 at 8:05 AM, Sirua2014 said:

just bought the car from rrg Toyota

If the car has been parked on the forecourt for some weeks before you bought it, then the rear brake pads might have left a rusty, slightly raised, 'witness' mark on the rear rotors, from where they have been sat still for so long with the handbrake on.  If it is this, then it will wear off eventually, of course.

Plenty of others have noticed, even on new-ish cars, that the brakes sound 'gritty' and a bit noisy.  In the earliest days after the model launch, I have an idea that Toyota fitted a (reformulated) set of pads  if the customer complained enough about brake noise.  I can't remember specifics, but apart from being quieter there was no other benefit to having the newer compound. 

Understandably, the brakes don't do as much work as on a normal car, so they don't get 'up to temperature'  as much as those on a normal car would, so perhaps the brakes are slightly noisier because they run cooler???  Just a thought....

Also, when you are braking to a halt quite gently, the regenerative braking will cut over to normal mechanical braking at somewhere around 5 mph-ish.  This transition might be accompanied by a slight click from the brakes and an obvious 'brake-friction' sound starting as the car slows further - look out for that one!

[CurranShelter]

On 9/22/2020 at 10:24 AM, Beekeeper D said:

Yes hybrids can run more quietly than petrol or diesel vehicles, which means you can notice things you otherwise might not! You will likely notice significant changes in tyre noise with different road surfaces. 
However, while driving the only noise the electrical systems themselves produce is the slight whine. 
You will notice some “mechanical” noises after you stop and the car progressively shuts down over a minute or two. Similarly, powering on is accompanied by the odd unfamiliar clunk and whirring.

I've often wondered what's behind these trademark noises in Toyota hybrids, i.e. what's actually going on behind the scenes. For instance, there's the sort of buzzy groaning noise when you open the driver's door (and at certain other times), and then a series of noises (clunk, whirr, click, whatever...) after parking and turning off the power. Can anyone explain (in more or less layman's terms) what the system is up to in these moments?

As to the original question, I've always found the brakes a bit noisy, but took that to be partly down to the regenerative braking system and partly (as others have said) just because the braking noise is just more noticeable without the usual noise of an engine running.

[Gerg]

1 hour ago, CurranShelter said:

there's the sort of buzzy groaning noise when you open the driver's door (and at certain other times)

I believe that's the brake pressure reservoir pump charging the fluid pressure up.  The more you use the 'conventional brakes', the more often it will run.  It doesn't run if you open the front passenger door instead, as you probably know.

When you engage 'drive' or 'reverse' from 'park', the transmission brake releases - it is motor driven on this car (Corolla, C-HR, Yaris, RAV4 are not, they use a mechanical bowden cable, which partly explains the different gearshifter). If a window is down, that can easily be heard (dis)engaging, otherwise quite hard to detect.

When the system is 'on', the inverter water pump runs continuously with a gentle whine. 

That's my take on it anyway, I don't know about the others!  ABS?

When does the engine water pump run?  And is it always at the same speed?  Anyone know?

[CurranShelter]

Thanks Gerg, I've been wondering about this for ages! Somehow satisfying to have an idea of what's going on when I hear this stuff (and I did wonder about the different gearshifts too).

[Gerg]

Look out for the transmission (park) brake release noise, if the car has been parked and the handbrake has not held the car perfectly stationary (i.e. handbrake not on hard enough), then the engine/transmission can become lightly stressed, as that is what is eventually stopping the car moving further, this loads up the rubber engine mounts as the parking/transmission brake is then supplementing the handbrake.  When the transmission brake comes off as you get ready to drive away, this sudden unloading of the transmission can make an unexpected, muffled, bang!  This can be unsettling if you don't know what it is!