Occassionaly when I start my car (an octy II L&k 2.0 TDi Est) I hear a loud bang which sounds like someone thumping the roof of the car above my head. There is always a sound like a cable moving too between the roof and the lining.

This only happens occassionaly and when it does the radio is switched on tuned to an FM channel. I wonder if it is the ariel cable that I can hear moving between the lining and the roof but have no idea what the loud bang is.

Anyone else had this problem?

Occassionaly when I start my car (an octy II L&k 2.0 TDi Est) I hear a loud bang which sounds like someone thumping the roof of the car above my head. There is always a sound like a cable moving too between the roof and the lining.

This only happens occassionaly and when it does the radio is switched on tuned to an FM channel. I wonder if it is the ariel cable that I can hear moving between the lining and the roof but have no idea what the loud bang is.

Anyone else had this problem?

Yes I've had that loud thump happen a few times on my 1.9Tdi Elegance. The first two times I got out expecting to see a dent in the roof where something had fallen on to it - but ... no evidence of any impact.

I believe the problem is to to do with the audio system - a sudden momentary pulse of bass through the speakers on switch on. I'm not sure what causes it but mine hasn't done it since I had a bad connection to the 6 CD changer fixed.

Not heard the cable moving bit though.

Exhaust banging?

If you take a bump fast, does it happen then? If so get the exhaust & mounts checked

This may not be the problem, but my radio used to make a loud bang when starting occasionally, fixed by the dealer with an upgrade? I cannot think of anything that could move in the roof space.

It's not the exhaust or anything else loose, as it happens when I first start the car in the garage. Lowflyer's description of leaping out expecting to find a dent in the roof is exactly how I felt.

It does sound like a sudden pulse through the speakers. I have checked most of the audio connections, indeed have changed some of them as I have removed the CD auto-changer in favour of a auxilliary input for MP3 and DVD. Before anyone asks, yes it did make the noise before I did that.

Stacon; when you say your problem was fixed by an upgrade, did you mean they changed the head unit or did a software upgrade?

This happened to me a couple of times when the car was new. First time I thought I must have imagined it, but the second time my daughter heard it too. However it has never done it again since that second time.

The dealer did a recall software upgrade on the head unit last time it was in for a service. Something to do with the radio draining the battery when left for a period of time. However, I havent had the problem since. Can only think it was included in the patch.

I'd get Rentokil in, sounds like you have rats in your loft.

It comes through the speakers, happened quite a few times on my Octy, never happened again once they re-flashed my radio on one of the services.

It's not the exhaust or anything else loose, as it happens when I first start the car in the garage.

Wifes punto did the same ONLY at start up.

If it happens even when the radio is off, it's worth considering

Turn stereo off and see if it does it.If not at least you know what it is after.