There is a strange thumping noise coming from my 2012 Scion tC ! It's like a drowned knocking noise whenever I am driving at around 25-40mph.

1. It doesn't seem tied to RPM.
2. I can hear it mostly at 40-60kph.
3. I can hear it even when I am coasting at that speed.
4. It gets faster the faster I drive. On the freeway it seems drown out, but I can't tell if it's because it's just blending in with the rest of the noises.
5. Cold, warm, hot, no difference in noise.

Noise: https://clyp.it/5e3w05fm

In case anyone wondering with clyp.it is, it is the first result when I searched Google for upload sound clip.

Alternative link: https://sndup.net/5yjt/unknown-engine-sound.mp3

It is the sound that's not the engine noise, the turn ticker or the road noise. You can hear it starting at 0:25 and pretty clearly at 00:36-00:48, and 00:58-01:19.

Can anyone help please?

Thank you

I have ran a Search but it doesn't seem like anyone else has the same problem, or I'm not searching the right keywords.

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I would say start by checking under the car for and check the tires. From the sound, it sounds like it could possibly be a bad wheel hub bearing. You could check by jacking up each of the wheels and try to move it, then if it doesn't move, try spinning the tire and see if you can hear the noise.

Must Watch Before Spending Money On a New Wheel Bearing - Rachects and Wrenches


How to Check a Wheel Bearing in Your Car (Replacement) - Scotty Kilmer

 

zhengli

Find the noise yet?

My guess: you have a piece of trim loose. Its flapping against the body at speed = wind induced, therefore not tied to a specific road speed or rpm. It prob has its best frequency at the speeds you mention

Could be anything from a loose splash shield around a wheel to a piece of fender trim to a b-pillar decal, etc


I too have a thumping sound, but its coming from under my car & it sounds like a bird has flown into me: a heavy "wet" thunk. Once every 45 seconds or so... It was more noticeable last fall. Havent noticed it since i've discovered the joy of my 8-spkr radio haha

Good luck tracking it down


Cheers
Azz

 

Thanks for both your responses! Unfortunately I still haven't found the source.

I finally had time to check the bearing as described in the videos, but don't notice any issues. Maybe it's because I can't spin it to 30-50mph.

I don't think it's a wind induced noise as it doesn't appear louder in high wind or low wind conditions, and it's very consistent 'book-book-book/thump-thump-thump' noise that's faster at faster road speeds, and slower at slower road speeds. It sounds like there was something stuck on the tire actually, but I swapped the front left tire with the rear left tire (where it appears to be coming from) and the noise remains the same. It happens about 3-7 times a second depending on how fast I am going. Can't hear it on a freeway.

Thanks for the ideas about the splash guard / fender trim. I will try playing with those and see if I can change the sound.

 

Did you every figure it out? I have the same problem exactly.