Intervaled Humming Noise At Highway Speeds

[honza]

Hi everyone,

Last week I bought a 2004 Avensis 1.6 (base model) with 59.500km from a Toyota dealer here in Hungary.

I'm quite satisfied with the car except for one issue:

At highway speeds in 5th gear there's a deep humming noise and very slight vibration coming from the engine with an interval of about 1 second on, 1 second off.

It almost sounds like a vacuum cleaner, but its not always the same intensity (dBi). Sometimes its more intrusive (and annoying), sometimes less, and it doesn't go away after driving for a while, rather it becomes more apparent. I can start to hear the noise when cruising at 110km/h and the noise level (dBi) increases when I cruise at 130km/h. At higher speeds (160km/h) the wind noise picks up and overtakes the humming.

The noise disappears when I engage the clutch. It also seems to disappear when I speed up on the highway, and it seems to blend in when I let the car slow down by itself with the clutch dis-engaged. I tried to replicate the problem in 4th gear (at 4000 RPM) but didn't hear any humming (normal engine noise was quite high, maybe that's why the humming wasn't apparent).

The dealer recommended putting on new tyres (they needed replacing anyway) but that didn't help. Otherwise the dealer had no further suggestions and said that these noise levels are normal in the Avensis. I guess I will take the car to other service centers to see what they say, but if somebody has any other advice please let me know!

Thanks,

Jan

[honza]

5th gear at highway speeds without pressing any pedals, I noticed that while slowing down the engine produces the exact same noise (except its continuous, slowly fading as RPMs fall). Does anybody know why this noise becomes intermittent when i press the gas pedal (to keep the speed constant)? Or what can be done to make the noise continuous rather than intermittent?

[honza]

correction: i was able to hear the humming even after de-pressing the gas pedal to slow down from 120km/h (3500rpm) in 5th gear (clutch also de-pressed).

i tried to listen for the humming in 4th gear @3500rpm but didn't hear it so i'm guessing the problem lies with the transmission.

any ideas?

[Beagh1958]

Just an idea, but you might jack-up front of vehicle & check for wheel bearing play ? Only problem is wheel bearings make more of a rumbling sound. Just something to check before you go looking for gear box or clutch release bearing problems.

[Beagh1958]

Sorry, just noticed car purchased from main Toyota dealership. Take your car back to them you must have some sort of warranty on vehicle ?

[honza]

thanks for the advice...dealer said the noise level is normal, he might fix it if i tell him the specific part that needs fixing/changing.

i will take the car to a mechanic next week, so hoping he will recognize the issue.

i noticed this post might be my problem as well due to waving characteristic of the noise.

http://toyotaownersclub.com/forums/index.php?showtopic=86608

[Beagh1958]

I will assume your car was purchased from official main Toyota agent. And if this is the case the onus is not on you to tell garage what the fault is, that's why mechanics go on official training courses so they know the product garage sells inside out. Your dealer sounds like they have a screw loose in the brain. If you have noise as described by yourself then it is not normal. It's for Toyota to find the fault & if said fault is covered by warranty all the better for you. If dealer told you noise level was normal then ask them to specify exactly what is making this normal noise that they don't consider to be a problem.

[honza]

hi again,

I took the car to another toyota service and they said that there's nothing wrong with the car...and when I asked a mechanic he said its probably resonance: at certain RPMs the engine or engine bay vibrates in a way which gives off a deep humming noise...which makes sense because it comes in waves almost like when u hit a tuning fork.

anyway, I tried to record a sample to give you guys an idea but the background noise is pretty high (120km/h):

http://pragueapartment.com/humming.mp3

so I ran the recording through a low-pass filter @ 50Hz, now the deep humming coming in waves can be clearly heard:

http://pragueapartment.com/hummingf.mp3

let me know what you think!

thanks,

Honza

[irishjay]

hi again,

I took the car to another toyota service and they said that there's nothing wrong with the car...and when I asked a mechanic he said its probably resonance: at certain RPMs the engine or engine bay vibrates in a way which gives off a deep humming noise...which makes sense because it comes in waves almost like when u hit a tuning fork.

anyway, I tried to record a sample to give you guys an idea but the background noise is pretty high (120km/h):

http://pragueapartment.com/humming.mp3

so I ran the recording through a low-pass filter @ 50Hz, now the deep humming coming in waves can be clearly heard:

http://pragueapartment.com/hummingf.mp3

let me know what you think!

thanks,

Honza

sorry the link wouldent work for me , but my car has a strange humming noise at exactly 1500 revs , toyota said it was fine checked my in jectors they were ok i also asked them to check the air intake box and filter as it had just been serviced but they said they were fine also so im stumped lol now i just turn the radio up!!!!!! im thinking maybe its the air filter vibrating inside the box ,, dont really know

[honza]

that's weird they work for me...maybe its trying to play them within the browser but cannot...try right-clicking on them and save-as.

[honza]

actually, it looks like there's no A record if I leave out the www., but my provider still has it in cache:

--

C:\>nslookup pragueapartment.com

Server: cache-ns1.tvnetwork.hu

Address: 80.95.64.6

*** No address (A) records available for pragueapartment.com

C:\>nslookup www.pragueapartment.com

Server: cache-ns1.tvnetwork.hu

Address: 80.95.64.6

Non-authoritative answer:

Name: agnes.nfrance.com

Address: 80.247.228.231

Aliases: www.pragueapartment.com, customers.discount-hosting.com

--

try these links:

original: http://www.pragueapartment.com/humming.mp3

filtered: http://www.pragueapartment.com/hummingf.mp3

and I just noticed I can upload files to this forum =]

hummingf.mp3

[cmia]

Does the humming happen in any other gear ?

[honza]

Does the humming happen in any other gear ?

nope, only in 5th...in other gears it sounds like normal constant engine noise, but in 5th@120km/h it takes on a low pitch and comes in waves...at 130-140km it stops...at 150-160km some noise comes in waves again but its a higher pitch and not as noticeable.

i'm pretty sure the pitch is lower in 5th@120 than in other gears @sameRPM, but maybe it just sounds that way because it comes in waves.