Help I lost the "Sound proofing"

MTND · Unread post by **MTND** » 11 Jan 2011, 21:46

Hi All

I was going down the A14 this evening and heard a noise where I drove over something! Upon investigation when I got home I found I'd lost the "sound proofing" from under the engine bay.
Can anyone let me know what problems this may cause me? I'm going to drop into Duxford if I can tomorrow to get them to have a look and see if they can help but I am also after any advice you can give please?

Cheers

Mark

Unread post by **DHallworth** » 11 Jan 2011, 22:07

A lot of XM owners remove them as they believe it corrodes the subframe as it traps the salt and grime between the cover and the car.

The one I had fell off my 306, I did a further 66k miles in it and it was still showing no signs of problems when I sold it.

David.

Xantidote · Unread post by **Xantidote** » 12 Jan 2011, 10:00

I wouldn't worry too much, but worth checking that no damage was done when the under-tray/under-shield fell off.

Bought my car at 3 yrs old. It may have had an under-tray when it left the factory, but it's never had one in my ownership. Now you won't have to remove it to change the engine oil! If my car had an under-tray, then I'd have always refitted it, on the basis that citroen designers considered it necessary to provide one in the first place.

I think there may have been discussion on the Forum in the past about pros & cons of the tray/shield

Unread post by **CitroJim** » 12 Jan 2011, 14:56

Xantidote wrote: I think there may have been discussion on the Forum in the past about pros & cons of the tray/shield

There was. I believe the conclusion was that the only effect was to reduce the oil temperature on diesels by a few degrees...

This was the thread, the undertray was only tangentially mentioned...

xmexclusive · Unread post by **xmexclusive** » 12 Jan 2011, 17:05

The undertray as factory fitted to 2.5 XM diesels had a wide strip of foam at the top edges. This seals between the tray and the front sub frame.
The subframe is not galvanised just painted black. It is also made up of lots of thin section steel sheet. The foam is OPEN cell structure so it fills up with water, (salt water in winter) and forms optimum rusting conditions.
On one of my XM's I got caught out.
The rusty sub frame got so bad it was just visible outside the undertray.
So the MOT man found the rust and failed the car.
The "catch 22" came when he also advised that if the car came back with that subframe weld repaired he was duty bound to fail it again.
His logic was that the subframe was a suspension component which may not be weld repaired under MOT rules.
Totally changed my views on XM undertrays.

John