I have just now registered and I thought I’d bring to your attention to what could be a fatal issue on the underside on an audi a3.

I have a 2008 a3 cabriolet and recently had its yearly mot, failed, on one item, rust on front lower suspension area,small part  and one advisory, a rear bush.

 

But when the garage took off the undertrays that cover the main chassis front to rear (both sides) it was found the the whole drivers side chassis was riddled with holes and passenger side, although better, had serious rust.

So my question is, how long did this took hold as this is not over 1-2 years and how damaging are the undertrays are as they hold all the moisture, crud, mud, and can’t be washed off with a jet spray.

The situation was, that it cost me just over £1000 for the garage to fabricate new panels but if the trays were not fitted it would have been noticed years ago and possibly rescued it before it got that bad.

Essentially if your ever thinking about buying an audi especially an cabriolet take off the trays before you buy as you could be looking at a whole lot of pain come mot time.

Thought I’d mention my situation and hope that I’ll find some useful info on here which I am sure I will.
cheers

Gary. 

I have not heard of this problem until now, however chassis rust is a part of the MOT test and should have been discovered long before it became serious. Has the car been used off road which might lead to a lot of mud or salt being thrown into the trays?

I was told by the garage owner this is (not usually to Audi I must admit) common with cars that have under body covers, including sill covers, as, the MOT tester is not allowed to remove or touch any fitted trays.

(If a child seat is fitted, the mot tester is not allowed to remove seat to inspect the seat belt, another crazy rule)

This, over time you can imagine, is a potentially dangerous situation,

The MOT guidelines should be changed so that all underbody structural parts are in full view.

it’s like at the moment you could have a rusty brake pipe but if it’s covered with plastic tubing, it will pass.

 

10 hours ago, 6709Gary said:

I was told by the garage owner this is (not usually to Audi I must admit) common with cars that have under body covers, including sill covers, as, the MOT tester is not allowed to remove or touch any fitted trays.

I find it hard to believe that a certifed MOT tester is legally allowed to pass a car that he has not fully inspected.

On 10/27/2023 at 11:56 AM, cliffcoggin said:

I find it hard to believe that a certifed MOT tester is legally allowed to pass a car that he has not fully inspected.

I agree but I suppose their job is harder if the undertray blocks their visibility 

I found the same issue under my 05 A4 avant quattro tfsi.  Nearly fell over when I saw the extent of the rust above the rear spring supports (hidden under the felt wheel-arch cowling) and bad rust all along under sills from rear to front hidden above the plastic undertrays.  NCT in Ireland is pretty thorough but none of this rust was spotted so the car flies through every year.   The rust stops where the plastic undertray stops i.e. where the chassis is permanently exposed and can dry out properly.

I'm getting the car welded.  Plastic undertrays/felt cowlings free to take away - belly will remain naked from now on! 

Thanks Michael, 

I hadn’t realised that the arches were covered - not good news. 
Most MOT testers cover their bums with an advisory similar to ‘Undertrays fitted’. 
Kind regards,

Gareth. 

2 hours ago, Mick in Kerry said:

I found the same issue under my 05 A4 avant quattro tfsi.  Nearly fell over when I saw the extent of the rust above the rear spring supports (hidden under the felt wheel-arch cowling) and bad rust all along under sills from rear to front hidden above the plastic undertrays.  NCT in Ireland is pretty thorough but none of this rust was spotted so the car flies through every year.   The rust stops where the plastic undertray stops i.e. where the chassis is permanently exposed and can dry out properly.

I'm getting the car welded.  Plastic undertrays/felt cowlings free to take away - belly will remain naked from now on! 

Wowzers! 

4 hours ago, Mick in Kerry said:

Ye gods. That's frightening.