Hard to find leak - help!

I have an 86 911 Coupe that has an impossible to find water leak. Sometimes after a heavy rain, I will find my floormats completely soaked...I am amazed at the amount of water. Other times, nothing. The leak appears to originate from the drivers side and it appears that the car may have been hit on the left front earlier in life (although repaired very well). I have replaced door and hood seals to no avail. All of the sealing surfaces appear fine and the windshield shows no sign of leaking though I can't be certain. Any ideas?? This is driving me nuts. Thanks for any suggestions....

You should have someone hose the car down with a garden hose while you sit inside and try to find the source of the leak.

Brian

Brian, thanks for your reply. I did that for a half hour and could see nothing. I'm truly at a loss and I don't want to take it to a dealer for fear of spending big $$$ and potentially still not solving the problem.

Does the soaked carpets come after you are driving it in the rain? If so there maybe water coming up from under the pan, such as where the brake rod goes through the floor and if the cover for the steering rack is missing that could be the source or there might be a hole down there somewhere? Try to use a high pressure washer under the car after you remove all the carpets with someone inside. Good luck.

It seems to happen even if the car has not moved for a couple of days so I'm assuming it's not the pan or other underside problem. I guess I'll have to try the soak test one more time and see if I can see anything. Thanks..

I had a similar problem. Tried Seak and Seal round the windscreen to no avail. Finally traced it to the air intake grille just below the windscreen. It depended entirel on how the car was sitting. Sometimes the water would run down perfectly and go in behind the grille which wasn't seating properly, down the trunking and soak the carpets starting of behind the gear lever. I removed the grille, bulit up thearea behind it with silicone sealant and no problem since. Try using the hose again but mask tape in some news paper below the dash but above the pedals. This will give you some idea if it is a low or high evel leak.

Thanks Bonnie...I had already removed and inspected the entire ventilation ducting and draining under the hood thinking that may be the cause but I never thought to check to see if water could run by the vent sealing surface and straight through. Thanks for the great advice, I'll keep you posted on the results!

Paul, in a lot of cases the problem that you are having is the angle of attack and pressure. I have had three leaking windshields that did what you are describing, but it always looked like it was coming from an upper door seal. I had one car with a sunroof, that would sneakily leak into the car when it was moved. Try different angles with the hose... maybe you will get lucky. Good luck, this type of problem can be a royal pain!

I had the same prob with my 81 SC. I used an air gun and blew from the inside of the window out, the hose trick didnt work. When I did this I began to see bubbles around the window seal. Once I found this out the seal got fixed--no more leaks.