Leaking washer pump
This Technical FAQ (How to...) has been carefully compiled by John Handford
I've just had to fix a leak from the windscreen washer bottle on my 225 TT which had emptied itself on the garage floor within a week . I was quite shocked when I got it apart!
I had read some reports of smells from mixing different screen wash solutions. I had even heard of tales of failing aliens if you don't use Audi fluid! I don't know what fluid had been in the car previously but I've been using Halfords £4.99/5litre concentrate for years so had been using that since I got the car.
The leak was apparent from the rear of the wheel arch where the bottle is hidden under the liner. I removed the wheel arch liner (just a load of torx screws) and could then see the bottle, along with some collected mud and leaf debris, behind the bottom rear of the liner, under the bottle. I also noticed some gooey white gelatinous mould. I cleaned up the muck and removed the bottle.
It had been leaking from around the screen pump. When I tipped the remaining contents into the kitchen sink I was shocked to see that it was less like water and more like a gooey gell with the consistency of a very dilute wallpaper paste!
I think there has been some bacteriologigal infection of the water which might explain the smell and goo - sort of battery acid / bad egg smell.
I suspected bacteriological material had crept past the seal interfaces and started a capilliary leak. I took everything apart and cleaned up the rubber seals with IPA. I also poured bleach into the bottle to remove the gunk. The bottle had no crack and was in perfect condition after a clean.
I discovered a leak in the screen (not alien) pump by blowing into it. In the photograph I'm pointing to the input flange joint under which the impellor spins (click to enlarge).
I tried taking it apart but it resisted, so I decided to seal the leak externally. I cleaned it out with IPA, dried it, cut off some 40mm diameter heatshrink tubing (note the hole/slot for the output pipe) and applied some hot melt adhesive all the way round the flange joint.
I then heated the heatshrink tube onto the end of the pump, melting the hotmelt adhesive, clamping the flange and sealing it all in the same process.
I also noticed that the alien pump was split near the electrical connector (pointed at with tweezers). This was not leaking and was probably not important but I put some heatshrink over this too.
I then assembled the bottle again, applying a little IPA for rubber seal assembly lubrication - it will eventually evaporate leaving a tight clean rubber sealed joint.
Then it went back under the wing.
I've never had a problem with Halfords screen wash before and will continue to use it, as the system is now clean and all the Audi fluid (or whatever) has been flushed out (spent some time pumping the Aliens).
I noticed, that there is no filter gause in the bottle design, to stop debris entering the pumps. The pumps have a shredder input design to pulverise any semi-solids, but I don't think this is good for the fine jets in the Aliens!
I think it might be a good idea to:
1) Flush out your bottle with water before adding a different fluid
2) If you get a bad smell - remove the bottle and clean it! (Or possibly add a little bleach to kill off bad bugs)
Anyway, it's all fixed now, for naff all cost, just time... Hope this helps someone else.
