Keeping screenwashers clean.

[davejazz]

So when things are a little bit quiet on here, I hop over to the MK.3 forum, as some of the tips are generic, and will transfer over to my MK4.

Such a tip to stop the washers from “gumming up”, was to pop in a sterilising tablet;… (remember all those years ago, with Milton and babies bottles, and sterilising feeding bowls etc.)

Sounds like a good, cheap, idea. 

Any thoughts?

[ColinB]

Depends what you mean by "gumming up". Milton is a disinfectant, so will deal with bacteria & viruses. In my case, living in a hard water area, the problem was limescale and Milton won't do anything about that. I now use de-ionised water with a good quality screenwash.

[Lord Voltermore]

Milton's fluid is basically a diluted form of Household bleach  (sodium hydrochlorite) . It would stop the build up of algae etc in the screenwash bottle  but not  something I  would want to spray over my car .

I would recommend using a summer screenwash in summer  (or diluted 'winter mix) which also often contain ingredients to help clear squashed bugs as well as supressing algae growth   And a decent winter mix in winter months  .  But as Colin points out some areas are prone to lime scale build up due to hard water.   De inonised water is a good idea but quite expensive. Maybe  rainwater from a water butt would solve the lime scale problem but more precautions may be needed to prevent algae growth etc,. 

Another problem in winter is the anti freeze ingredients in winter mix is quite volatile  and  can evaporate from the washer jet nozzle, leaving plain water which can freeze as a small plug in the washer jet.   To minimise this I use minus 20 winter mix even though it seldom gets this cold in the UK.
While we are on the subject, with winter coming,  be aware that diluting the various strengths of  winter screenwash doesnt produce the frost protection level  you might expect. For instance adding 1 litre of water to 1 litre of minus 20  mix does NOT  make 2 litres of minus 10. .Check the label.

 I have a screenwash strength hydrometer  that measures the actual strength  of screenwash . I can draw a sample from my washer bottle and verify I am adequately  protected as the weather gets colder.   Mine has a floating scale  so looks similar to hydrometers for checking radiator coolant strength and battery acid strength.  But they are not compatible. Make sure you buy the correct type. 

[nowster]

Depends what you mean by "gumming up". Milton is a disinfectant, so will deal with bacteria & viruses. In my case, living in a hard water area, the problem was limescale and Milton won't do anything about that. I now use de-ionised water with a good quality screenwash.

Dilute citric acid or lactic acid is good for clearing limescale residue. The sort of stuff you use to clean out coffee machines.

If you're in a hard water area, perhaps use bottles of pre-mixed washer fluid instead of concentrate and tap water.

[Bristol_Crosstar]

I did have a problem with my screenwash turning to a jelly-like goo on my previous Crosstar. I mentioned it when I took the car in for a service they said to clean it properly they'd have to take the front bumper off to get it out and that it would be a big job! I tried the Milton solution and together with using a long this brush managed to improve things slightly, it didn't damage the paintwork when I sprayed it out. Fortunately on my new car there isn't any issue (at the moment).

[CRC]

I've tried a few screenwahes over the years, but the best I've found is the pink Autoglym additive. Not cheap, but you don't need very much at all.

I don't worry too much about it freezing in the winter so don't put in the amount it recommends, but my experience is that it's the best by far for removing road grime ..... and it smells nice as well.

Never had one block up when using this.

[coldstart]

Another problem in winter is the anti freeze ingredients in winter mix is quite volatile and  can evaporate from the washer jet nozzle, leaving plain water which can freeze as a small plug in the washer jet.   To minimise this I use minus 20 winter mix even though it seldom gets this cold in the UK.

A commercial "winter mix" usually contains isopropyl alcohol and some ethylene glycol which both have boiling points (well) above 80 degrees centigrade (yes, even the "azeotropic mixture" boils above 80°C!).
Of course: Evaporation at the exposed noozles happens somewhat faster. However, an occasional washing cycle renews the liquid in the nozzles and - at least in my parts - gritting salt forces quite frequent additional washing cycles during the cold season

Commercial fluids usually are based on deionized water as well, so limescale build-up won't be a problem.