Bless it - I've been running my XM since 2002, picking it up with 66K, and now passing 168K.

The disadvantage of it being fairly reliable for the last few years is that I've skimped somewhat on underside inspections. It has usually sailed through MOTs with just a few advisories. There have been no reasons to work underneath, hence spot any worsening rot.

Today this bit me hard - it failed it's MOT with corrosion to the nearside rear sill plus two adjacent points directly under front seatbelt mounts, and the corresponding inner sill. There appears to be an odd "rust trap", a section of long member which has a circle cut into the bottom of it. This appears to have rotted out from it's radius.

Probably five hours' welding by my Citroen independent. At £40/hour. PSA's anti-rot treatment does not appear to be what it was on my old '91 Pug 405.

Additionally, the tester decreed that the steering pinion valve leak had now got to a stage where it needed attention. It has been weeping since 2002. Large drops of LHM convinced him that it was time for some attention.

Another fail point was the unions by the nearside front engine bay cross-member, both leaking, but hopefully cured by new seals.

All a bit of a nasty surprise. I post this so that others don't end up in the same situation.

r

Hi rg

Sorry that the rusting has caught up with your XM.
The galvanising does help but has a very different effect on the way XM's rust.
Most of the problems are hidden as seams and trapped areas hide the rust until it is serious. My view is that XM's generally rust from the inside outwards.
Cills are a particular problem but the front subframe can go as well.
Rear end of estates are another trouble spot.
More then half of mine have needed patching now.
I have just decided to stop patching a M reg 2.5 exclusive at only 120k.
We put in over 10 plates a couple of years ago to get it an MOT.
There is a small rust hole under virtually every bubble in the failed underseal.
Topside it look fine, no visible signs.
The tan interior can move to a better bodyshell and the rest turned into spares.

John

Thanks for the reassurance, John.

It did surprise me, to be honest, and I feel a sense of "professional guilt" for the neglect - the last time I needed any welding for an MOT pass was on a 1974 Viva, circa 1985.

I think my subframe is too well treated with escaping LHM to rot at the moment. The sump pan does not look very youthful, though...

r

Could find a spare sump for you but the bad news is that on a 2.5 it cannot be changed insitu. The XM rusting seems to often be where there is a failed covering membrane.
Strut head tops, failed underseal and where undertray fits the front subframe.
The seams of the pressed galvanised panels and the burnt areas round the spot welds are other rust starting points. Rusting is fastest where there is a trapped mixture of air and water. So the uncluttered outer skin of the body shell dries quickly with virtually no rusting. The inner enclosed sections retain moisture for much longer so is prone to rusting while the little pockets of failed protective coating rust fastest by keeping the steel virtually permanently damp and in optimum rust conditions.
None of this is easily spotted because it is not the normal way cars rust.
Add in the famous Citroen rust treatment protects all myth and you are not looking anyway. Fight the rust, the car is worth it.

John