Smelly windscreen washer fluid.

[Jocko]

A week or so back, I noticed that there was a horrible smell permeating the car when I used the screenwash. Then yesterday I checked the fluid levels and as soon as I removed the screenwash cap there was a horrible smell of rotten eggs (H₂S).
Today I pumped all the fluid out using both the front and rear pumps alternately. The fluid was spotlessly clean, just smelly.
I have now topped up with all season concentrate. I hope the smell goes too.

[swhull]

Sounds horrible, I don’t know if this is true  but I remember hearing someone contracting legionnaires disease from old windscreen washer fluid. Always try to remember to make sure my windows are up before spraying 

[culzean]

A week or so back, I noticed that there was a horrible smell permeating the car when I used the screenwash. Then yesterday I checked the fluid levels and as soon as I removed the screenwash cap there was a horrible smell of rotten eggs (H₂S).
Today I pumped all the fluid out using both the front and rear pumps alternately. The fluid was spotlessly clean, just smelly.
I have now topped up with all season concentrate. I hope the smell goes too.

Bacteria and mould love screenwash especially as weather warms up - I never really had a problem because of all the mileage I did and I hate a dirty screen, but to get her indoors to use the screenwash was like drawing teeth. I was the only one that topped anything like that up and I knew that during a week less than an eggcup was being used and although the screenwash I was using smelled nice her excuse for not using it was that the screenwash smelled bad,  no good trying to explain to a female that it smelled bad because it was staying in the bottle too long, so I just ended up going for a drive and pumping it all out every so often.

[Jocko]

I have never had a problem before, no matter how warm the weather (and it is not that warm at the moment). I too use loads of fluid as I hate a dirty screen. On a sunny day, I will use more fluid than on a winter's day.
What I think it may be is Wemk Screenwash Tablets. I bought these and found them rather ineffective but have been chucking one into the reservoir now and again, to use them up. They may be reacting with the all-seasons concentrate.

[Westy36]

I used to have it happen a long time ago because I was too tight to buy screenwash!

I treated myself to some of this a couple of years ago. I'm a convert, smells lovely and have been buying it ever since.

https://www.halfords.com/motoring/screenwash-and-de-icer/halfords--10-concentrate-screenwash-2l---berry-611735.html

[mj1sjc]

I once had the same problem with a corolla verso. I figured out it was due to two different windscreen wash types being mixed up once poured up and possibly thats why it happened. This was during the last summer. I had to use a hand pump to get the fluid out, and the poured in fresh water with bit of dettol to clear everything out. After that I used just one type of a screen wash

[embee]

Mixing screen wash brands has always been (anecdotally) prone to causing problems of one sort or another. They are after all a concoction of chemicals, different brews are quite likely to react, at worst forming jelly like stuff which can clog the lines.
When I've switched brands I usually try to run the bottle more or less empty, put in some fresh water and pump a reasonable amount through to flush it, then fill with the new stuff so it is predominantly one brand and not a roughly equal mix of two types.
I've noticed the sulphur type smell in my summer toy car when I've left screen wash in it over winter. I prefer to empty the bottles now when it's being laid up.

[culzean]

Mixing screen wash brands has always been (anecdotally) prone to causing problems of one sort or another. They are after all a concoction of chemicals, different brews are quite likely to react, at worst forming jelly like stuff which can clog the lines.
When I've switched brands I usually try to run the bottle more or less empty, put in some fresh water and pump a reasonable amount through to flush it, then fill with the new stuff so it is predominantly one brand and not a roughly equal mix of two types.
I've noticed the sulphur type smell in my summer toy car when I've left screen wash in it over winter. I prefer to empty the bottles now when it's being laid up.

A lot of screenwash contains various forms of alcohol, which many bacteria see as food ( in very high concentrations it will kill many bacteria,  but they are getting resistant to it). Bacteria also live in fuel, aircraft have to have 'disinfectant' added to fuel to prevent things growing in the fuel -  an airliner almost crashed last year when an inexperienced guy misread the instructions and stuck a whole lot too much into fuel.  Adding ethanol to petrol encourages bacterial growth,  which produces acids which can attack certain metals in the fuel systems of older vehicles ( stuff like brass and some seals ).

[Kremmen]

Whenever I take my car in for service, and it's happened every year for decades, even though my screenwash is topped up to the brim, they invoice me for '1 part screenwash'.