A4 Avant rear screenwash problem

[green A8]

First post on this forum, I thought this might help other A4 Avant owners.

My other half runs a ‘98 Tdi Avant. Up to several weeks or so no problems with the car whatsoever. The problem started with my weekly fluid level/tyre pressure checks revealing that the windscreen washer bottle was around 75% empty. Odd, but no problem, I simply refilled it. The following week same scenario, A bit puzzled as the Wife doesn’t normally use the screen washers that much, I refilled the bottle to the brim once again. I ran the car over the pit and checked the underside of the washer bottle for leakage, none was found. The third week same problem. This time I ask the Wife if she’s been using the washers more than usual, I get a very firm ‘No! But the rear screen washers packed up and it makes a funny noise’ So there you have it an expert diagnosis !

I get in the car and test the rear screen washer. She’s right it has ceased to function, and it does make a hissing sound which seems to be coming from a small plastic trim above the carpet on the passengers side footwell when the washer is activated. Then I remove the rubber mat in the passenger side footwell and discover where all that missing screen wash fluid has gone the footwell is awash! I next removed the plastic trim just above the footwell carpet and discover a large amount of wiring and connectors, all of them wet and sudsy. On further investigation I discovered that there is a very simple male/female push fit type join in the plastic tubing that takes the screen wash to the rear of the car. Located conveniently just above all that wiring! It had simply separated. I rejoined the two ends and the problem was sorted. The rear screen washer is happily working again. And a few weeks later, the washer bottle remains fairly full.

Drying out the electrics and the carpet was fun! I ended up having the interior valeted much to the Wife’s delight. So there you go folks, not all Audi A4 Avant, wet passenger side carpets are caused by blocked drains. Shame the same can’t be said about the A8. But that’s another story………………..

Kind Regards.

Paul.

[spartacus 68]

It normally stops working when the weather is cold. Same thing happened to me and I must have used the rear screen washer more than normal (roads were very dirty). Personally it's a design flaw. The inter-connecting pipes should somehow lock into position, not just pop together. Double-check the nozzle on the rear window wiper. It sometimes gets blocked with debris. Stick a needle in it and use plenty hot water.

[David1953]

Same with me yesterday. Have pushed the pipes together and will not use rear wash until the spring!

[amatty]

Hi - It has been very cold in the UK recently and for the second time my rear washer failed. The first time about a year ago was the joint parting under the dash near the front left footwell and squirting the fliud under the carpet. I found about half a gallon of liquid in the footwell which was in danger of ruining a lot of electrics. Luckily the car was parked down a slope and after drilling a hole in the floor most of the water drained out, but it took ages with the carpets propped up and fan heaters to dry out the carpets.

The problem was that the water had frozen in the pipe.

I put heatshrink over the pipe before snapping it back together, shrank it over the joint and then wrapped it in tape.

This year it packed up again and my repair had held, BUT now another joint has parted behind the trim over the right rear wheel arch and water has squirted over the electronic box for the remote locking system - luckily without damage.

I can see the pipe to the tailgate when I undo the right hand inspection cubby hole where the lights are at the rear, but cannot find the end behind the trim below the window and can not find how to remove the trim to fix it.

This seems to be a design flaw in that the pump seems able to provide enough pressure to pop the pipe connectors apart and soak sensitive electronic parts. Perhaps operation of the pump should have been inhibited below a certain temperature !!!

PS Water can also get under the front carpets from the front plenum chamber if the drain holes get blocked - as frequently happens when the leaves fall.

Help and please see my request for help on 28December on how to remove the trim !!

[spartacus 68]

I can see the pipe to the tailgate when I undo the right hand inspection cubby hole where the lights are at the rear, but cannot find the end behind the trim below the window and can not find how to remove the trim to fix it.

If the repair at the front footwell has still held, then the interconnecting pipe at the tailgate would be a good place to check too. It's definitely there. Same thing happened to me on numerous winters. If it's leaking there there will be a pool of water next to the light cluster. As described it's on the right hand side inspection hole, behind sound-proof or insulation padding. If it's dry, then look at the wiper nozzle itself. I does get blocked and cause water to back-up. As a last resort, check the water reservoir. The pipe may have detached. I think it can be accessed from the engine bay (if memory serves me). Worst case scenario - you'll have to remove the plastic wheel arch liner to locate.

Get someone to use the rear wiper while you do a search.

[David1953]

Looked in the right hand compartment this am as mine not working and yes the pipe had separated. Both pipes clearly visible at the top of cubby hole. Pushed them together and rear screen washer in operation. I like the idea of heat shrink tube but wonder whether they will just blow somewhere else?
David

[amatty]

Thanks for all your comments and I have established that the pipe has parted behind the right hand wheel arch trim and there was water in the area of the space behind the rear light cluster.

My problem is that I can not find the end of the pipe under the trim - there is little room to get a hand in to feel for the pipe and I can not see it. The next stage would be to remove the trim over the wheel arch to gain access to the pipe join, but having removed all the fixings I can see, I have been unable to take off the trim so far, even after much levering with wide blade screwdrivers.

I will try finding the pipe now with a lamp and dental mirror and may have to make a tool with a hooked slot at the end to try to grab and then pull through the disconnected end of the tube.

Trim removal would however be best - anyone got any ideas how please.

[green A8]

I had a look at the back end of our Avant a couple of hours ago. You can JUST see and reach the joint in the wheel arch section. On our car it's OK so I left well alone.

I'm left pondering how to fix this problem I can't say that I like the idea of screenwash pouring all over all those wires at the front of the car. I think I'll introduce some modification.

Kind regards.

Paul.

[amatty]

Looked into top of panel opening at right rear using a dental mirror and torch so that I could see under the wheel arch trim and located the free end of the pipe. Managed to plug the connector together but unable to pull the pipe any further out so that I can easily hold the connector together with heat shrink /tape - may do this later.

It is hard to decide what to do in the end, because next time the pipes freeze and I accidentaly operate the rear washer spray, no doubt the pipe will part somewhere else. Perhaps now that I know where the weakest link is - and that it is in an area which seems to do little harm and the water drains out under the car, I will not bother to do the heatshrink mod and live with the not to serious consequences if the joint pops.

As you all know if the front joint parts it is a big problem, with water under the front carpet and in the electrics !!! They wrote off one A4 in the area because the CPU etc. was wrecked and it was going to cost more than the car was worth to fix it - though in this case I believe the water was a result of blocked drain holes in the plenum chamber which has the same effect.

Matty

[elefant_man]

My avant has the same problem apart from mine has split the pipe in the passenger foot well I was hoping to get away with plugging it back together and some heat shrink but it has a good 2-3mm split on the lower side of the pipe.

Does anyone know how hard it is to replace the pipe. My initial thought is to replace the whole pipe front to back with standard washer pipe.

Any thoughts on this would be greatly appreciated.