We got an Ocatvia mk 3 less than 30 days ago. Ex MOD lease car so no service history beyond what the dealership did and the off lease MOT prior to civillian registration. It had a second dealer MOT and full service with signs of parts replaced and work done.

One week after getting it we set off to visit relatives (elderly) but had to turn back due to this noise less than 5 miles away. It was a juddering / banging noise that came on at 35-40mph and went off when slowed below that. That is how we described it at that time.

We informed the dealer and he told us to go to a local garage and he would sort out payment (3 month guarantee). The garage was an independent VW specialist with a good reputation locally. He did a 30 minute check and found nothing but surface rust on the brake discs which he got rid of with a bout of strong braking. It did have that secondary braking noise that I pretty much guessed the cause and expected that to go with time. The garage said that they could not detect an issue but that they would not say that there is not an issue just that it did not present to them so they could not diagnose it. We paid the half hour labour for that.

One week later it came back but it became a kind of painfull pressure feeling that affected driver and passengers' ears. One kid was in a bit of discomfort and complained that it hurt him. The driver (my partner) slowed and it went. She slowly increased again but only to about 30mph so did not experience it again.

Now what could the issue be with this car? A juddering bang (as in regular banging noise and relatively high frequency IIRC) with a pressuree feeling with it. Note I was in the car driving the first instance which did not have the pressure detail. I was not in the second occurrence so details are secondhand about the pressuree detail.

It has happened twice but we do not use this car much. We drove the car 50 miles from the dealership then since that we have perhaps done about a couple of hundred miles or less. We mostly have only driven to the nearby small town 5 miles away (10 miles round trip) about 20 times over the 3 weeks we had it. We are a 6500 mile per year car user since we use public transport mostly (trains to work).

We have gonee back to the dealer to ask for a refund. He has come back with a defensive about needing it back to take to his local VW garage to inspect and diagnose the fault, but also to determine the severity. If it is not a severe fault then he does not have to refund is the gist of his repl

So I have a few questions. What is this fault likely to be? A question for the automotive experts there will be here. Second question is whether we have the right to a refund if this is not a sever fault as they said? My thinking is that this is so intermittent that it is highly possible it does not occur when the VW main garage inspects it, like our local VW specialist garage found. IF they cannot identify then what is the legal situation? Can we return it for a full refund on the basis of the issue as we experienced it??

BTW the car is a decent 2018 reg car. It is what we need and we were very happy with it until this issue presented itself. We were actuall;y thinking about spending money on improving it, which we have never wanted to do with any other car. We were looking at rear parking sensors and possibly other things like reversing camera. It is a basic model so we were thinking about upgrading. It has winding reear windows so perhaps change to fully electric windows if that was not too expensive mod. So it is a car we would have preferred to keep, but that is not something we want if it has a fault that presents itself randomly without being diagnosed.

So any advice on the issue cause or our consumer rights should we push for a refund?

Forgot to say, this is a 1.6TDI manual gearbox Octavia mk 3.

Hi this may seem a silly question but did you have the rear windows down but the front windows up or only open a small amount? if we do this then you do get a real air pressure sensation and noise in the car, it could be something as simple as this. this sensation does increase with speed so fits the above 35 mph you said.

Edited 6 July, 20256 Jul by seriesdriver

Check that all the plasic undertray fittings are properly secured to the brackets / holes in the floorpan. There may be something loose that "flaps in the breeze" above a certain speed.

I have a 2000 BMW 740 Sport as a hobby car and the garage that serviced it and changed the front O/S thrust arm didn't check properly and the undertray part covering the front O/S fell off on the way home. They were adamant that it was secured properly but I know couldn't have been otherwise it would not have fallen off.....

I have loose undertray in other cars and a van. This is not something flappping at all. It is like a pressure thing in the car. Starts out as a kind of juddering that then becomes like a pressure build up as it got past 35mph. It was like taking off or landing in a plane to give you an idea of the discomfort.

It was not the window open at the back. We have a basic model that has hand wound rear windows. We have had it with the windows open and fully closed so far. It is worsee with the windows closed. When I experienced it the windows were open in the front only as we had set off and it wwas hot, thee AC was slow to cool it down due to sun direct into windscreeen for hours. The second time it was raaining hard so all windows were shut or occupants would be getting wet. The kids in the back did not open the windows.

I have heard someone say they got something similar when the air filter compartment had been closed with the seal pinched, or something like that. Apparently they found it leaked air into the main car at a higher pressure that caused discomfort. Another possible is a low frequency "sonic boom" from the rear suspension on all models of the Mk3 Octavia. That had a few things that can be done to help with that issue including putting a spare tyre in the boot, a volvo acoustic damper on the rear axle or torsion bar or somthing like that and even loosening the rubber in thee boot lid that contacts the boot surround when closed (although on hatch only).

If it is the first thing with the air filter housinig then opening it up and closing it properly should solve it. If the second then there is no solution as it is part of the design of the car. There are things that can help reeduce the effect.

Of course it could be something totally different. I have no idea about that. I do know it is nothing to do with windows open or closed or loose undertray. In fact I first wondered about that and when we got the car home I was straight under the car looking at that so definitely nothing loose on, under or around the car that is flapping. Thanks for ths suggeestions though. More things we know to look at the more things we can rule out.

Edited 6 July, 20256 Jul by Octavia_Newbie25
Added appreciation comment

As a random guess, there are pressure-relief vents off the boot. They might be blocked or damaged, I suppose.

What a strange problem.