Recommended washer bottle additives?

[T-Cut]

No big name screen wash additive will affect the paintwork. The manufacturers do too much research for that to happen. All screen wash formulas contain a detergent (like in washing up liquid) which make the water 'wetter'. This enables it to clear away grease and grime better than straight water. They often contain isopropyl alcohol to improve the cleaning and lower the freezing point of the solution. You have to use vast amounts to get below say -10 degrees though. The active ingredient isn't the same as used for washing up liquid and you should avoid using Fairy Liquid etc because they often contain salt to thicken them. This leads to corrosion in the wash reservoir and elsewhere any metal parts are in contact. Good additives contain a softener to prevent lime scale and will also contain a bactericide to prevent the growth of smelly bugs and agae in the reservoir. Cheap formulas soon degrade and allow cloudy material to grow. This is usually the stuff that blocks the jets. The stuff you pour into the bottle is clear but after a few weeks (summer especially) it turns clumpy from bacteria. Use bleach to clean grotty bottles and rinse well before refilling with good stuff.
In my early days, I did the research for an additive going into at least one big name screenwash formula. I won't say which.

TC

[black olive]

I thought the government had cancelled winter due to everyones " carbon footprint "

[windrush]

I've all ways used halfords with out any problems

[Keith]

One word of warning

Don't overdo the additive or if you do use it regularly as some of the various types seem to be heavier than water and settle out in to the washer bottle where they congeal into a snot like goo

Result - threads on blocked washer jets and inactive pumps.

I am now in the habbit of using plain water which if freezing weather is expected I syphon out and add just a pint or so of screen wash sollution which I then water down once the cold snap has passed

It is cheaper doing that as well

[Jules]

Fairy liquid contains salt now you don't want to be putting salt on your cars now do you?

A product I don't recommend so far..... Comma screen wash.
Cheap & nasty from a Motor factors.
It grew that black bacteria and cloudy jelly in the original container after only one week!!!
This was after diluting it to 20% strength but before putting it the car!! (decided to use it as weed killer instead!)

[shakennstirred]

i have used the halfords winter ready mixed screen wash for the past 5-6 years without any problems