ramans

So I'm having an issue with my 1990 964 C2 Coupe where the insulation on the passenger (right hand) side was soaking wet. The insulation has a channel running down the middle of it and it was only wet in the inside insulation not the outer one, so it seems unlikely to be the doors. I checked under the car for those drains mentioned above and ran a nylon wire fish up them they seemed clear as far as the fish would go but it wasn't very far (8-10 inches maybe)

it seems to me from where it's wet (the insulation was also not wet up the foot board, only on the flat part below) that the leak is coming from the vents, or from underneath as I hadn't noticed the carpet being wet. So what I Wanted to know is have you guys noticed the carpet being wet in this case? OR has anyone seen a leak from below. I'm going to spend some time this weekend pouring water on the washer nozzles to check those. For the check on the CCU above it was mentioned that you should have someone operate it while someone is in the trunk listening for the servos, what are they operating? The Fresh/vs recirc air switch?

We've had some huge rain here lately before I found this also the car was detailed and in my shop where the humidity got super high over a snap (super cold concrete floor + a warm snap with wet outdoor weather). It wasn't soaking wet but definitely wet enough to feel it, I stuck a reversed vacuum cleaner hose under there for an hour or so and it dried out, then I left it propped for a few days and stuck some dessicant under there as well.

Thanks,

-R

Rocket Rob

I think its unlikely that the water is coming from below the car, although you should verify all of the body drain plugs are intact. The common causes of water inside the cabin are:
1) Plugged HVAC drains (see above)
2) Leaks at the windshield
3) Leaks at the doors or door glass
4) Leaks at the hood

How do you find them? Its a process of elimination. Good luck with the repair.

Vandit

^another source could be leaks from the washer jets at the cowl. Either exterior water leaking around the base of the jets, or the input lines for the jets leaking above the HVAC unit.

ramans

Rocket Rob and Vandit thank you from my post I have checked the HVAC Drains, and asked a question about how clear they should be. I don't think it can be the door because the wetness would have to be near the door, and the piece next to the door was completely dry it was the next piece over (well it's one piece but there's a channel between them) does that jive with your thoughts?

As I also said I'll be looking at the nozzles, and the windshield, what I'm wondering is how to validate the vent is closing for fresh air

-R

Vandit

The position of the fresh air vent at the top of the HVAC box shouldn't matter. The water drainage system in the box is designed to properly route water to the drains at the bottom regardless of the fresh air flap position. The only difference being whether it drains it through the evaporator drains or just the rain drains, but they both go through the HVAC box and out the bottom.


A place I would look is at the rubber bellow for the fresh air intake. It goes from the top of the HVAC box to the bottom of the cowl. At the bottom of the cowl it is bolted into place w/ a sturdy flange w/ gasket, but at the top of the HVAC box, the rubber is only glued into the plastic HVAC box. With time, the elasticity of the bellow can pull the bellow away from the airbox and I could see how this could create water ingress since it spills out rather than being routed through the HVAC box and out the drains.

ramans

Thank you,

This is under the bonnet up front? Is it obvious where this is? Am I looking for the thing circled in red here?

Vandit

That's the one. There's a plastic cover over that area, take it off to reveal the servos and that piece.

This is really a process of elimination thing. Remove the wet stuff and dry out everything as much as possible, then introduce water to the exterior areas one by one and keep monitoring for moisture.

DobermanDad

I have leak I mine I need to repair. Haven't had a chance to debug it yet because I got the car just as winter started. I think mine is probably the windshield seal, but I could be wrong. I guess it was replace and apparently didn't help.

I'll be adding a Rennline full race track mat and floor board seeing the carpet is gone on the driver's side. But I wanted to anyway, so I guess less work removing the carpet there LOL!

ramans

Okay I'll take a look at that in the next few days, the servos I was referring to are spoke about in post 5 of this thread where it says this:
-R

Vandit

I had not read that and was unaware of that feature, but I don't think that feature or a failure of that feature would create puddling in the car unless you're driving through a monsoon for a extended period of time. That feature is likely there to prevent water from misting you in the face when you crank up the blower while driving in a rain storm.

ramans

Realising this is an iterative and exploring process, one of my first questions remains, will the carpeting be getting wet or is the water coming in from these sources somehow coming down the firewall all underneath the sound padding?

boxsey911

This is exactly where water was getting in on mine. Took years to find it! I'd suspected windshield seal and fresh air intake as the culprits because I got the leak when spraying water over both of them. It was only when I poured a little water directly on the nozzle that I found it. Strangely it seems to be the right one (passenger for US but driver for my UK car) that usually leaks.

The solution was to prize the nozzle up, separate the rubber gasket, clean it with silicone cleaner, clean the scuttle and then press back in place. No more leak!

Greg_V

I had a similar problem. Painters tape and rainy weather helped me quickly isolate. For me, I ended up using a little Permatex flowable silicone on the front and rear glass seals (both body and glass side). Water was running down the underside of the carpets and pooling in the rear footwells. Since sealing, car has stayed dry.

I ended up running the Permatex along the scuttle seals I just replaced as well as the outside edge of the frunk seal. That may be the end of a two year battle to dry out the front trunk, knock on wood.

Streetdaddy

Mine was coming from washer nozzle seals that werent replaced when car was repainted.