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2018 Passat SE w/Tech
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Discussion Starter · #1 ·
I've learned in the past after owning several VAG vehicles, that summer blended washer fluids specifically the RAINX variant that's supposed to be formulated for dissolving bugs better, SUPPOSEDLY corrodes Washer Reservoir parts, and specifically fouls the sensor.
Apparently it's the silicone or whatever ingredient that makes glass more slippery, and water bead off, that causes this fouling.
I have no definitive proof, but heard it from my service advisor and a few others that know more about VW's and Audis than me.

So, I'm looking at mixing my own since I don't really need Rain-X's special formulation of silicone juices or whatever magical elixir they put in their branded sauces that fouls sensors, and did a preliminary search:


THe prevalent ingredient in the SUMMER blend recommendation is GLASS CLEANER, which is mostly ammonia based.
I don't have an issue with that, other than buying glass cleaner is literally more expensive than simply buying a gallon of washer fluid.
Ironically, the BEST cleaner for bugs on my M-Cycle Helmet visor in the summer, is Non-Ammonia aerosol Glass Cleaner that I also use on my tinted windows. o_O

Now, I'd LIKE to avoid the use of Methyl-Alcohol, which is the PRIME ingredient in most auto washer fluid sold nationwide, as it is an environmental pollutant. Primarily, this stuff is designed for the average motorist who cant remember that Non-Alcohol based fluid freezes in the colder months. I Am NOT that person.
I'd like to use a liquid that removes bug guts, costs less, and has a smaller environmental impact, as well as won't harm my paint.
I'll continue to research, but would like to hear from some more knowledgeable on this topic, and see what you use.
Florida residents in particular! 馃

gr
 

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2018 Passat SE w/Tech
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Discussion Starter · #4 ·
You guys lack imagination.

That cheap crap is just Methanol and water, and doesn't do squat for bugs.

CHEAP yes, but its just like dumping a bad bottle of Vodka on your windshield. :rolleyes:
 

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I wish I could help you out, but I use so little washer fluid it doesn't really matter. I have had my Passat since September 2020 and have never added fluid. Whatever is in there either came with the car when I bought it or was topped off by the dealer at the 20K or 30K service.
 

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Correct rain x will screw up your sensor and you'll get an indication that its low not matter how full it is. My MKV's sensor is toast because of rain-x. :(
 

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2018 Passat SE w/Tech
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Discussion Starter · #7 ·
Went with 1 gallon distilled water ($1), 1/2 cup ammonia (.25) and 1tbsp liquid soap (.001)
So far so good.

Might experiment with White Vinegar instead of ammonia on next batch.

Happy mixing.
gr

And PROTIP: extend the life of your wipers by cleaning them periodically with SIlicone Spray and a Scotch Brite Pad
 

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Correct rain x will screw up your sensor and you'll get an indication that its low not matter how full it is. My MKV's sensor is toast because of rain-x. :(
I have also had the Rain X stuff mess up the spray jets as well.

I do like the Rain X wipers though.
 

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Was told by Audi/VAG guys several years about Rain-X fouling washer reservoir sensors, but never heard of bad nozzles. :confused:
I had the Rain X fluid mess up the nozzles on a General Motors vehicle. I never tried it in a VW vehicle, but didn't want to risk it, so I only used the Rain X windshield wiper blades on my VWs with good results.
 
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