Our garage is stumped with a problem so I thought I’d throw it out there to the great STW hive mind for a laugh. They’re having another look on Thursday so you’ve a few days to make a guess before they hopefully actually fix it.

’07 Honda Jazz, automatic CVT gearbox. Sometimes when driving there is a rhythmic thudding with a frequency of approximately four a second that you can feel through your feet and hear (it’s a deep sound). I can’t make it happen in neutral on the drive, it doesn’t happen when driving around town, but when driving over 30-odd mph it happens quite frequently. It appears that going over around 60mph it either stops happening or the car is shaking so much (poor old Jazzy) that I can’t feel/hear it anymore.

First guess was the CVT which needed a flush anyway, so that’s been done and it still happens. One guess is wheel bearings are going, another is something to do with the driveshaft which sounds like it could get expensive.

There’s a prize* for the most accurate guess when it is eventually sorted, so what do you think?

* Prize is fame and glory in this thread.

Inner cv joint on one of the shafts would be a suspect.

Would that not increase in frequency as the road speed increased?

If your car has coil suspension check the rear springs.

Op said it does increase with speed

P.s. it has a period of about 4 seconds at idle. Frequency is in Hz.

Big ends

Check for funny tyre wear, especially on the rears. Make sure the surface is nice and level right across the width.

TheBrick – Member

P.s. it has a period of about 4 seconds at idle. Frequency is in Hz.

But the OP said: “frequency of approximately four a second”

…4 per second…., which is a frequency…..4Hz.
The period is 0.25 seconds.

No idea what the problem is though.
EDIT – although my only thought was what Rockhopper said above. Run your hand around the inner edge of the tyres & see if you can feel a wave/ripple. I’d expect that to be more of a low rumble though, like a knackered wheel bearing sound.

One square wheel?

Stans corals in the tyres

’07 Honda Jazz

Werthers Original vibrating in glovebox.

1) engine undertray flapping in the wind.

2) I don’t know much about CVTs, but as a guess, some problem with the belts slipping or jumping inside the box.

God such pedantry 😉

The thumping frequency doesn’t change with speed so I don’t immediately suspect the tyres. It appears at around 30mph and disappears (or is hidden by road noise) around 60mph. Frequency and volume doesn’t change in that range.

Sounds like one of the engine wheel hamsters isn’t running straight..

[video]http://youtu.be/X1kcTdzKb_E[/video]

Christ on a rubber bike.

TheBrick – Member
Op said it does increase with speed

No he didn’t.

TheBrick – Member
P.s. it has a period of about 4 seconds at idle. Frequency is in Hz.

No it doesn’t, he actually states he can’t make it happen in neutral, which is pretty much the only time the engine is truly idling, no?
And a very common usage of the word ‘frequency’ is: the rate at which something occurs over a particular period of time or in a given sample.

Now that’s cleared up we can get back to playing “guess the noise”!

🙂

Werthers Original vibrating in glovebox.

It’s M&S Curiously Strong Mints, actually.

(that’s actually true, but I bought them because they come in a metal tin which looks just the right size for tubeless tyre plug tools honest!)

Check the engine and gearbox mounting.

im going to say loose wheel nut.

But the OP said: “frequency of approximately four a second”

I completely missread that sentence dispite rereading it. I blame phone based posting

Wheel balancing off?
Misfire from the engine? Have the coil packs ever been replaced?

Driveshaft balance weights, worn suspension wishbone bushes, worn steering rack bushes?

Coil packs were replaced about two month ago.

Is it a diesel?
Can you feel it through the steering wheel?

Air filter box or engine cover loose and is resonating?

Petrol and no I can feel it through my feet (and hear it).

Deffo gearbox. Probably wrong oil used-specific Honda sourced oil only.
Take it to Honda your local garage will have no idea what they are looking at.

Loose undertray or heat shields underneath?

Thankfully STW doesn’t operate a real life car garage! There is no way I’d take a car there!

How many miles on the car?
How often has the ‘box been serviced/fluid changed?
Who ‘flushed’ it recently? Honda or local garage?
What oil/fluid was used?

Always serviced and flushed at a Honda garage, the last flush was a bit late but only months late. About 80k on the clock.

Heavy metal cd stuck?

rossburton – Member

Coil packs were replaced about two month ago.

Thats the most likely cause then – something they did when the work was done.

The only part if a car that hasn’t been named is the sun visors. I bet it’s them.

If it’s a proper CVT that means it will hold moderately steady revs throughout the ‘gear’ range doesn’t it.

If that’s the case can I bet on an element of it being something in the middle area of the gear box where the chain or belt runs. That might also explain the steady frequency.

Nobody’s mentioned the Magic Seats! There might be a pot plant wedged in behind the driver’s seat – one of these sounds about right…

hydrangea-macrophylla-lets-dance-rhythmic-blue

Who wins?

Someone’s locked in your boot.

Bloody garage changed the appointment so it’s going in on Tuesday instead.

Well, the dealer think its the driveshafts and they’ll need replacing.

They had the dignity to look ashamed when saying the retail price for genuine parts is £900 *each* considering that’s not far off the value of the car, and suggested either unofficial parts or ebay for replacements.

Somewhat tempted to get a second opinion, partly as the local garage should have lower service costs…