Buzzing/humming Sound Coming From Front Of Car While Accelerating

[Redfreddie]

Hi everyone,

This post is about my Mrs car this time (yes, we both have 400h's :) )

I drove it yesterday and noticed it made a horrible kind of humming/buzzing noise as you accelerated, when I asked her she said it started happening recently and was getting worse. Just wondered if anyone may know what it could be, I'll assume it's hybrid related as never heard noise like that in my life on a petrol only car ! Hopefully nothing to major but any advice welcomed, obv she'll get it checked out fairly soon but one thing we have noticed is that garages don't seem keen (or won't) work on our cars, even servicing they'll only do a basic one, so the only option she probably has it to take it to a lexus dealer to get it looked at,

Cheers,

Col.

[ColinBarber]

Does it happen accelerating when just on electric or only with the petrol engine running?

[Redfreddie]

Hi Colin,

I only noticed it when accelerating, so when both petrol and electric being used to drive the car, I'll take it out later and check it out just to make sure,

Cheers,

Col.

[Redfreddie]

although from memory (mrs out at the mo) it still made the noise when I came off the accelerator, and it was a droning noise as it decelerated to, so at that point no petrol engine I'm assuming ? I will take it out later and try various things to try and isolate it a bit

[Redfreddie]

OK I've just been out in it, the noise is coming from the rear of the car, when running on electric only it's as quiet as anything, and accelerating is ok too to start with, but as you go quicker the humming noise gets louder, then as you decelerate the noise comes down with it. I'm assuming it is something with the rear electric motor as that's the only thing in the rear I can think of, but everything appears to be working ok and there are no error codes ... So stumped for now but will get it checked out, just thought I'd mention it on here in case anyone has been through a similar experience and can shed any light on it :)

Cheers,

Col.

[rayaans]

OK I've just been out in it, the noise is coming from the rear of the car, when running on electric only it's as quiet as anything, and accelerating is ok too to start with, but as you go quicker the humming noise gets louder, then as you decelerate the noise comes down with it. I'm assuming it is something with the rear electric motor as that's the only thing in the rear I can think of, but everything appears to be working ok and there are no error codes ... So stumped for now but will get it checked out, just thought I'd mention it on here in case anyone has been through a similar experience and can shed any light on it :)

Cheers,

Col.

What tyres are on the rear? Tyres can make a humming sound. My Wife got Sunny SN3800's fitted to her Merc on the front to my horror, I gave her a good ol' shout as they make whirring, washing machine sort of noises the faster you go.

Id expect the hybrid warning light to come up if it was to do with the hybrid system and the Check AWD light too if something was wrong.

I imagine its either the wheel hub or bearings. This is the most likeliest. Any change in noise when turning?

To check if its the transmission, accelerate until the noise gets really loud, stick it into Neutral and check if the noise is still coming.

[Redfreddie]

Hi Rayaans,

The tyres are Bridgestone Potenza RE O31 on the rear, but they haven't been changed recently and the noise has only come on recently and has got louder over the last week.

I'll try the neutral test later as well just to see if it goes or stays :)

Cheers,

Col.

[billgatesisaconman]

Could it be a wheel bearing ?...

[rayaans]

Could it be a wheel bearing ?...

Yeah most likely it is.

Way to find out - stick the car on a jack, manually rotate the wheels yourself and you should be able to tell.

[ColinBarber]

The rear motor doesn't get used that much unless accelerating quite hard so I doubt it is that. Could be the diff, a wheel bearing or maybe a brake calliper sticking.

[Redfreddie]

Thanks all, I will check out wheel bearings, hopefully it is something simple and not expensive :)

[Redfreddie]

Tried the neutral test, no difference so still making noise ...

If it was wheel bearings, wouldn't I notice it at lower speeds to, as no noise at all up to about 30 mph ?

Cheers,

Col.

[rayaans]

Tried the neutral test, no difference so still making noise ...

If it was wheel bearings, wouldn't I notice it at lower speeds to, as no noise at all up to about 30 mph ?

Cheers,

Col.

With wheel bearings the noise tends to change when turning so listen out for that.

Although tyres are all the same, best check all the tread depth to make sure they're similiar. Odd tread depths on one axle can give you humming noises as can odd wear of tyres.

Sticking caliper - look for excessive dust on one wheel and signs of heat ie glowing rotors after a long drive. Car would pull to one side when braking too.

[ColinBarber]

sometimes the noise from a bearing at low speed isn't enough to be heard and only becomes apparent at speed.

If you have the window open can you hear it at lower speed?

[Redfreddie]

Hi Rayaans,

I'll check for sticking caliper, sounds like that's a possibility.

Thanks Colin, I did have the window open earlier and couldn't hear anything at all at low speed, also when going fast there is no obvious noise from outside, but inside the car you can hear it whirring, all very odd but I will check it when the Mrs gets home for possible caliper sticking,

Cheers,

Col.

[billgatesisaconman]

Check your wheels to see if they are hot, the rears should be pretty much stone cold, if your caliper is stuck it can be very hot ... so watch you dont burn your fingers ...

[rayaans]

Check your wheels to see if they are hot, the rears should be pretty much stone cold, if your caliper is stuck it can be very hot ... so watch you dont burn your fingers ...

Use the back of your hand mate,

[Redfreddie]

I'll use the Mrs's hand ;o)

[billgatesisaconman]

Check your wheels to see if they are hot, the rears should be pretty much stone cold, if your caliper is stuck it can be very hot ... so watch you dont burn your fingers ...

Use the back of your hand mate,

Are the back of your hands fire retardant ? ... lol

[rayaans]

Check your wheels to see if they are hot, the rears should be pretty much stone cold, if your caliper is stuck it can be very hot ... so watch you dont burn your fingers ...

Use the back of your hand mate,

Are the back of your hands fire retardant ? ... lol

Nope lol! But im assuming you wouldnt try and touch the wheels while the brakes are glowing red!

However, the back of your hand is less sensitive to heat compared to the fingers and palm. In other words, if you're in a house fire and want to check if the fire is behind your door, you'd use the back of your hand as your palm would stick to the door and remove the skin :O

[billgatesisaconman]

Only pulling your leg m8 ... couldn't resist it, life would be pointless without a little humour don't you think ...;-)

[rayaans]

Only pulling your leg m8 ... couldn't resist it, life would be pointless without a little humour don't you think ...;-)

Could try it with heat proof gloves but then you wouldn't know if it's hot would you? Lol

I know a guy who tried feeling the heat from a stuck caliper on his cheek. Got his face stuck to the wheel and a permanent Audi logo on his face lmao

[ChrisKaye]

Had to be an Audi driver! ;)

[rayaans]

Had to be an Audi driver! ;)

cant drive anything else now hahaha!

[PCM]

Hi everyone,

This post is about my Mrs car this time (yes, we both have 400h's :) )

I drove it yesterday and noticed it made a horrible kind of humming/buzzing noise as you accelerated, when I asked her she said it started happening recently and was getting worse. Just wondered if anyone may know what it could be, I'll assume it's hybrid related as never heard noise like that in my life on a petrol only car ! Hopefully nothing to major but any advice welcomed, obv she'll get it checked out fairly soon but one thing we have noticed is that garages don't seem keen (or won't) work on our cars, even servicing they'll only do a basic one, so the only option she probably has it to take it to a lexus dealer to get it looked at,

Cheers,

Col.

Did it get resolved?