Don´t know why

[spirit r]

water is coming out of the windscreen washer spray valve on the driverside if I drive the car. I open the vent hole in the cap of the water reservoir but it doesn´t help.

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Whats the explanation?
Thomas

[KiwiDave]

Thomas

Same thing happens with mine (and probably others as well). I'm thinking it could be a valve inside the tubing which is supposed to prevent water from draining back into the reservoir. I think this is usually contained within the Y connector.
May well happen if you take a right or left corner?
Of course, it could be something else entirely.

Dave.

[codge]

The Y connector perishes (Disintegrates), caused by the sunlight through the scuttle panel (vent panel). Why the jet leaks water out I don't know.
Maybe the water left in the pipe is sucked out by the lower air pressure at the nozzle when driving and the disintegrated Y piece allows air to come in to replace the water?

[spirit r]

clairvoyant Dave: The answer is completely correct:
The Y connector perishes (Disintegrates), caused by the sunlight through the scuttle panel (vent panel). Why the jet leaks water out I don't know.
Maybe the water left in the pipe is sucked out by the lower air pressure at the nozzle when driving and the disintegrated Y piece allows air to come in to replace the water?
I checked the y connecter and could see the little capillary crack.

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The hose clip are 9mm and 10mm there are diffrent hose.I take two jet from Serie 2 so I have more water on the windshield.

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Great Help
Thank you Thomas

[ian65]

so there was a one way valve in the Y connector? I never knew that either..... good call Dave.

[spirit r]

Sorry ian you missunderstood. The fault was a capillary crack in the y pipe. The UV in the sunlight take off the the softener in the plastic y-pipe.
Thomas
There was no one way valve inside the tubing which is supposed to prevent water from draining back into the reservoir.

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[codge]

Imagine a lower air pressure at the nozzle created whilst you are driving. If your tubes are full of water sealed up within the pipes right back to the pump/bottle then I think the lower pressure cannot lift (suck) any water out. But if air can get in at the Y connector then it's an easier lift to suck out of a short piece of pipe.

The pure physics people on here will rush to say it's not 'lift' or 'suck' but more a case of air pressure pushing up at the pump/bottle or at the Y connector.
But that's just practicalities, it's the same effect.

That's my take on it.

I like the anti UV tape Thomas. But you have got about 25 years of life in the new connector without it. Still good call.

[ian65]

yeah, sorry, my mistake, too many Daves on here giving plausible answers

[codge]

Imagine a lower air pressure at the nozzle created whilst you are driving. If your tubes are full of water sealed up within the pipes right back to the pump/bottle then I think the lower pressure cannot lift (suck) any water out. But if air can get in at the Y connector then it's an easier lift to suck out of a short piece of pipe.

And another bit of thinking.
Does the pressure in the scuttle space (louvred panel space) build up as the car rushes through the air. Building up from the base of the windscreen perhaps?
That air pressure can then get into the Y connector where its split and create a pressure differential relative to the air pressure just at the exit of the jet?

And maybe the Black Forest gets more sunshine than rainy Britain? So you might have a bit less time than 25 years?

Codge

[Lucky]

Does the pressure in the scuttle space (louvred panel space) build up as the car rushes through the air. Building up from the base of the windscreen perhaps?

This is exactly what happens, Dave, that's why most manufacturers have sourced cabin air from there for about the last 100 years This is also something well understood by our American friends when they coined the idea of the "Cowl Induction Hood" as was even an option on some of the more lively muscle car variants way back when. The pressure wave builds up at the base of the windscreen and can actually force cool, pressurised air back under the trailing edge of the bonnet (or hood, even) coupled with the fact that the engine bay is a low-pressure area and thus adds a slight suction. The aircleaner can then scavenge this to advantage... as modelled by Rich's bonkers 9-second Nova here;



Interestingly, this also means that aftermarket vented bonnets like the FEED one for the FD RX-7 which have their vents along the trailing edge are actually doing more harm than good, because they are supposed to suck heated air out of the engine bay but they can't at anything over about ten mph due to the high pressure wave forcing it's way back in. Admittedly some of this is counter-intuitive just looking at it, but aerodynamics is a funny old thing. Most hot air evacuated from the engine bay goes down under the car via the trans tunnel and floorpans, this is why diffusers can be so effective by hurrying this airflow along and easing it's re-introduction to atmosphere at the other end