[Stevieno1]

My M2 is the first BMW I've ever owned. I'd just been using standard diluted screen wash from supermarkets/Halfords car specialists store etc. Used these in cars for 2 decades and never had a problem.......

About 14 months into M2 ownership my washer lines clogged and had to get them flushed; BMW told me I need to use their official anti grime screenwash to prevent it happening again. Okay fine - so I got a 5L container worth from a BMW reseller online but there's no usage instructions on the bottle.

Reading various answers online whether to just pour it undiluted or use a dilution ratio of 3/4 water - 1/4 solution.

Does anyone know from experience what ratio is best? Ideally I'd like to dilute it somewhat as obviously pouring it in neat means I'll go through it faster and its not the cheapest stuff to buy.

[Suhb]

Is this the dilution chart you're looking for?

https://www.fcpeuro.com/public/asset...jpg?1496490043

[Stevieno1]

Originally Posted by Suhb

Is this the dilution chart you're looking for?

https://www.fcpeuro.com/public/asset...jpg?1496490043

Thanks for this - really appreciate it. Though a bit confused as I emailed BMW customer Services and they have replied and told me it can be used undiluted - but the message in the top right of your screenshot clearly states it requires dilution.

[Suhb]

If you have the big galon jug, use it straight. That’s already premixed.

If you have the little concentrate bottles, those have the dilution chart right in the bottle like the one I linked.

[Stevieno1]

Originally Posted by Suhb

If you have the big galon jug, use it straight. That’s already premixed.

If you have the little concentrate bottles, those have the dilution chart right in the bottle like the one I linked.

Yeah its a 5 litre container I have which is equivelant to 1.3 US gallons.

[Maynard]

If it is concentrate it will say so very clearly, and you don't want to use it straight - it will have that label with mix directions (assuming not, or you wouldn't have asked, so must be a premix). I was glad to find this at fcp, becausee to me it works much better than the regular 'blue' store stuff.

Perhaps related - I was warned when I bought mine to never ever use any of the ones containing silicone (usually orange, like RainX); this apparently gels up the seals in the pumps and causes expensive failures. OK to use the alcohol-based ones. The dealer said they'd had so many of these cases that they warned new owners specifically (and then wouldn't cover it if you went ahead and jacked it up).