Water leakage problem

[76Datsun280z]

Whenever it rains out, water will drip inside the car from underneath the dash only on the passenger side. We just had new weather stripping put on and this didn't solve the problem. Today when I was washing it, we used the hose to try and figure out where it was comming it. When we'd poor the water over the cowling on the passenger side, water would start to immediatley drip in underneath the dash. We toor all the carpet out on the passenger side to let it all dry out since the carpet got soaked. Is there a hose or a gasket that is underneath the cowling that could be causing water get underneath the dash? Or even rought that would be causing this? I'll be taking the cowling off to inspect under there, but before I do that, I need to know what to look for. This is a pretty serious problem that we have to fix as soon as possible because we just had a new radio installed and don't want it to get damaged because of the water leakage, not to mention the wiring. Thanks again guys for all your help that you have given me, it's been a real help. -Austen.

[DatsunZsRule]

Have you ever removed that little grill and looked in the cowl area before? My guess is it's probably junked up with debris and isn't draining the water out the bottom like it should. If thats the case, hopefully it's just a matter of cleaning it out good so it can drain water out again and not rust problems

[Z Excellence]

Where mine was leaking was the windshield rubber molding. Take those 3 or 4 screws out that hold the finishing strip over the rubber. Then put some water on it. I ended up using a flashlight during a rain storm in my driveway to fine this.It would only leak when the car was not moving.Also check the rubber diverter strip on the top front edge of your passenger door.Hope this helps.

[76Datsun280z]

Have you ever removed that little grill and looked in the cowl area before?

It has been off before and we did clean it all out, so we don't think that is the problem.

[Ed]

Not sure if you 280 is designed the same as the 240. But under the cowl (the piece between the hood an the windshield) there is a fresh air intake. It is right about the area you are describing the water is coming from. It has a "snorkel" type build. It's about a 6" square 6" tall. There is a "hood" that covers it to prevent water from entering. Along the base it is sealed with caulking. This caulking is probably where your water is entering the car. Water will drip down your heater fan area.

[76Datsun280z]

Not sure if you 280 is designed the same as the 240. But under the cowl (the piece between the hood an the windshield) there is a fresh air intake. It is right about the area you are describing the water is coming from. It has a "snorkel" type build. It's about a 6" square 6" tall. There is a "hood" that covers it to prevent water from entering. Along the base it is sealed with caulking. This caulking is probably where your water is entering the car. Water will drip down your heater fan area.

Thanks, I bet that's it. It'll probably have to be next weekend when I get a chance to pull the cowl off, but I'll let you know what I discover. Thanks.

[240znz]

Ed is onto the right track there.

You also could look into the following. I'm the same a Ed in that I'm not up to speed on the 280Z as we never got them here.

I had the same problem, wash the 240z and water would end up on the floor boards, but only if I fired the hose into cowl slots.

Water collects under the cowl and is directed to the fender ends where a drain is located. The drain exits into the cabin where it is connected to a thin walled 25mm diameter rubber tube with a 90 degree bend in it. This tube passes through a rubber grommet on its way to the outside of the car where the water is dribbled down between the inner fender guard and the door pillar. I found that the rubber tube had perrished and water was just pouring out but hidden as it drained nicely into the jute sound deadening on the inner firewall. That stuff mops it up and holds it hard against the inner firewall so as to greatly help the rust monster. A very bad design and I am suprised that they keep it there for the S30 range.

It is not easy to get to either, but I think you should be able to loosen the clamp and remove it. Good luck finding a replacement, just about as hard as finding a rear hatch hinge rubber boot.....ie forget it.

There is a thread about replacing this tube with a longer version that ensures that the water exits lower down the fender/door pillar area. Here it is http://www.classiczcars.com/forums/showthread.php?t=19467&highlight=cowl+drain

[jmark]

Our '78 280Z has the same issue.

[280z1975]

I had a similar problem, replaced the front windshield and the gaskets on both the front and rear windows, turned out the new gaskets wouldn't seal as well as one would hope. Since I provided the gaskets I couldn't go after the company that installed the windshield. I then bought a small bottle of clear bathroom sealant and ran it all the way around the windshield where the glass meets rubber. Made it look pretty good and since then there has been no leaks ... It leaked on the bottom corner of each side of the front windshield and one bottom corner of the rear windshield.

Hope this helps ...

[76Datsun280z]

Thanks for the tips and the help guys, the windshield gasket we had replaced last summer, so that shouldn't be the problem. I'll let you know what we find out when I take the cowl off next weekend.

[EScanlon]

The "snorkel" that Ed refers to, is the Fresh Air Intake. Depending on the condition of the flange that raises it's edge up and into the "mushroom" cap umbrella (rain shield), you may have some leaks through there. For the most part, those leaks would show up on the sides or at the bottom of the Fan Cage Housing.

The Cowl Drain on the other hand, has it's flange (actually a tube) projecting INTO the passenger compartment. It is there that the Cowl Drain Hose connects to and then exits via the Kick Panel and grommet into the plenum between the fender and body. If the rubber hose has corroded, cracked, or disintegrated, your cowl drain is literally draining into the car.

While OEM Drain Hoses and regular replacement hoses in this size may be hard if not impossible to find, you can just use 1-1/2" Clear PVC tubing, available at many Pond / Pool servicing establishments. With careful use of a heat gun, you can soften this enough to mold and shape it into the required double 90°-S curve required and then route it out behind the flapper valve behind the tire.

Here's another post recently that needed a bit more clarification on the drain hose system I devised:

http://www.classiczcars.com/forums/showthread.php?threadid=24649

HTH

Enrique

[JimmyZ]

It could also be that the floor of the cowl area has some rust holes. Had to fix these on my 240. Look where the firewall abuts the cowl floor for rust/water flow.