Leaky Punto

Had same problem with a Fiat Uno. Firewall punched for RHD or LHD, with plugs, plates, and blind grommets in the unused holes. Some plugs were firtreee with mush heads, and in the wrong way round, mush head on the inside, not the engine side. So drive in the rain and water saturated the carpet. Apart from replacing them the right way round, and some were hard to get at from the engine side, I made with some glass fibre to seal things up good and proper. Also had boot flooding problems but that's another story and cure.

I had a car flood after the drainage from the chaber with the heater intake became partially blocked, in a storm the water filled the chamber and came in through the heater intake. I found two inches of water in the footwell. If there's water in there or it drains slowly you got a blockage, it may be visible & easily cleared or you may have to use a pipe cleaner to clear it.

Mike

In through the engine compartment bulkhead / firewall?

These are always tricky.

First clue is what type of carpet?

In my expereience most Fiats are fitted with 100% waterproof carpets. To fiind this out you really need to examine the backing of the carpet. In the waterproof ones the whole backing is a plastic/pvc sheet.

If the waterproof type then unless the water level in the floor of the car (floorpan) has come high enough to breach a hole or cutting in the carpet, e.g. where the lower seatbelt mounting bolts on the inner side sills pass through the carpet, the leak must be dripping/running/flooding onto the upper surface of the carpet.

Another check is to remove the driver and passenger front/rear door tread strips/moulding and lift and feel the floor and felt underlay. If they are dry then the leak is coming onto the top surface of the carpet.

It is a hard long process of elimination. Water ingress is a real bummer.

Does the car have a sun roof? Are the drain holes blocked? Is the car parked on a slope? Any signs of damp/staining round the glass areas.

Three examples of ingress that I have debugged may give you some clues as to 'how to think like water'.

1) Fiat Coupe. On the doors there is a black moulding on the inside of the door around the lock area. I was experiencing water in the rear footwell. In this case water was running down the outer edges of the door apperature seal till it met the plastic moulding. This left a little step where the moulding cross at 90 degress the door seal. In warm wet weather not a problem. In cold wet weather this 'step' would not tightly hug the moulding so the water ran down the outside of the weather seal to the moulding, then ran along the moulding seal interface to traverse the weather stip and then carried on running down the inside of the weather strip, onto the tread plate and onto the top of the carpet.

2) Fiat Uno. 'A' posts (the front post that the door are bolted to) are hollow. By design they drain into the sills and out of the sill drain holes. Look behind any car door and you will see that where the hinges bolt to the main bodywork and where the door straps locate there is plenty of opportunity for water to naturally penetrate these areas. In my case, when I parked the car on our drive (in one position which was inclined & tilted) I would get water in the floorpan beneath the carpet. Took me months to figure out that the problem only occurred in this parking position and not in any of the other three places I could park. In the inclined and tiled position water that entered behind the out door edges was safely running down the 'A' and 'B' post external reacceses. However on the 'A' post it was entering the door strap hole, running down the inside of the 'A' post (no problem as it will drain out of the sill). BUT sadly on its way down it hit the wiring loom for the central locking and electric windows and ran along the loom to the inner inside of the 'A' post, entered the car and continued to run down the 'A' post and under the carpet on the inside of the car! Solution was easy but rather fiddlely!. Tease excess loom wiring out of the door and the car to create a 'drip loop' inside the 'A' post.

3) Fiat Tempra. Sun roof. Water in passenger floor pan. Water appears to drain away from the sun roof try to the underside the car as expect. Well most did. The windscreen pillars were foam filled after the sun roof and drain hoses, which run down the windreen pillars, were fitted. However the internal the internal pillar tim is fitted afterwards. One of the trim pegs had punctured the soft drain hose, (which was now firmly held in place by the expanded foam against the inside of the window pillar), and water traversed the 'peg' to the inside of the car and behind the windscreen pillar trim. From there it was another hidden trip into the floorpan!

Sorry I can't answer you question directly other than to say 'imagine you are water' and do forensic like examination of the crime scene, feeling touching, looking, smelling etc. for traces of anything you wouldn't expect. Also car postiion, weather, temperature etc.

Enjoy!

Nick /////

if this is an early mk2 punto there is an official fiat water ingress modification involing lots of silicone sealer and the corrners of the scuttle/wing. early mk2's are bad for water leaks.