Whenever i drive on the motorway at 70 I hear a very strange noise from the back of the car.

I think i might be going crazy, but it sounds like the aerial whacking off the roof or the rear window.

The noise doesn't occur at slower speeds, not does it seem to tie in with bumps in the road.

Has anyone else experienced this, or have any idea what else it might be?

I am hoping it's nothing dangerous as it only seems to occur above 70mph!

Cheers

Hatch or estate. It  happens on the hatch, if the rear hatch is not shut properly . If you have an inter hatch release see if it's tight to pull . If not check for obstructions round the lock. Other solutions are available ( such as letting wife/GF/partner out of boot)

have you look underneath the car for anything loose or hanging down such as the undertray

Thanks for the suggestions guys. Its an estate but I will check the latch! 

Anything else you can suggest i check for? It's definitely at the back so won't be the undertray

Hey isambard. Check your back box heat shield. They rot through and vibrate at speed. Happened on my daughters recently. Something to rule out anyway.

This could be a good shout actually! I saw the heat shield looked rough recently, but how could you rule it out? I'm guessing its not the easiest thing to remove!

On my daughters fabia you could see where the shield had worn/rotted away, allowing the shield to drop. My plan was to remove the nuts from the studs and refit with penny washers behind the nut to secure the shield again. But the two studs just necked off ( I think there is four in total). So I used plan B. A decent sized selftapper with said penny washer and plenty of sealant to prevent rot. Not perfect , but did the job. I was dubious about removing the heat shield altogether as its obviously there for a purpose.

FYI- it's not a heat shield ( according to local exhaust place where bloke has an Audi) -VAG fit a double skin back box, but it's possible that part of the outer has come adrift (unless it's GF/PARTNER/WIFE) in the boot.

^ Yes the OEM back box is double-skinned but there is an aluminium heat shield attached to the underbody. I took the rear section of mine off as got fed up with it rattling and corroding around the fixing holes. I wouldn't remove it any further forward though.

 

Edited 3 May, 20179 yr by TMB

7 hours ago, VWD said:

FYI- it's not a heat shield ( according to local exhaust place where bloke has an Audi) -VAG fit a double skin back box, but it's possible that part of the outer has come adrift (unless it's GF/PARTNER/WIFE) in the boot.

Yup. Definitely a heat shield. I should know, I refitted the bugger !!!!!!!!!

On mine, it's possible that there's no heat shield fitted, as I watched the exhaust bloke remove the second rusted layer from the back box, with no evidence of a heatshield.

Thanks for the suggestions guys, I finally got chance to have a look yesterday,and found BOTH a loose heat shield and a rotten second skin on the exhaust!

I had exactly the same issue but at around 50mph. It was the heat shield in my case too.

On ‎5‎/‎12‎/‎2017 at 08:52, isambard said:

Thanks for the suggestions guys, I finally got chance to have a look yesterday,and found BOTH a loose heat shield and a rotten second skin on the exhaust!

Glad you got it sorted isambard