Hi folks,

The missus had been complaining of a musty smell in her 2010 fiesta. I've liftes the carpets to find a swimming pool in the front and rear passenger footwells.

I've ended up cutting out the sound proofing/carpet underlay as it's totally rotten and fetid. The floor pan of the car itself looks fine, with no signs of rust eye. However I've found two fairly wide hairline cracks in the seam sealer, between the floor and the sills - pictures attached.

One crack is at the rear corner of tge floor where the back passenger bench starts, tge other is at the front roughly where the A pillar meets the floor. The one at the front seems to be allowing the water through into the car.

I've put some gutter seal over the cracks as a temporary measure to stop any more water getting in, however the concern is why has this happened and is it indicative of something seriously wrong structurally?

The car has never been in a crash and the local Jennings body shop have suggested it's nothing major to worry about and just to seal over it, however I don't just want to bodge it.

Just wondered if anyone here could offer any insight if they've seen anything similar and if it's something more sinister to worry about.

Thanks for your time and help

I wouldn't worry about this meaning a structural strength defect providing nothing looks untoward on outside of car eg. spot welds on the sills pulled apart (extremely unlikely but I did have a Triumph TR7 which did have a number of spot welds that appeared to have ripped themselves apart).

But also I suspect that water might not have come through there either. It does not look like a likely place for the water ingress .

 I would dig through some of that sealant with a screwdriver and see if the metal underneath the sealant  is rusty. If it is rusty and damp there, slopping sealant over the cracks will trap the damp in and encourage rot.

Thanks for your reply.

I've had a look under the car, around the sills and chassis rail area. It all looks fine and is surprisingly clean and rust free for an 8yr old car. 

Re: water ingress, the crack towards the rear of the car definitely isn't letting water through, however the crack at the front does seem to be the point of ingress into the cabin. Only thing I can think is with it being at the foot of the A Pillar/Wheel arch is that when water is draining via the scuttle and down behind the wheelarch it Is somehow finding it's way through.

We've just had a ten minute downpour a couple of hours after I applied the gutter seal over the crack and touch wood the footwells have remained dry, will keep an eye on it over the weekend and do a hosepipe test.

If that holds up okay then I will do as you suggest and dig off some of the sealant and see what lurks behind. 

If all looks okay what do yiu recommend to reseal with? Someone at work mentioned tigerseal?

Thanks again