A business colleague recommended RainX Washer Fluid additive as a simple way to improve the cleaning power of the washer fluid, particularly in the summer months to clean bugs off the windshield. Being a RainX product it also had the added benefit of beading the water during a rain storm and improving visibility. I have used the original RainX product for years and liked it so this sounded like something worth trying . . . 4 oz in a gallon of washer fluid, pretty simple!
Filled up my reservior as prescribed . . . about a week later I noticed a Low Washer Fluid Warning. I was surprised that I had gone through that much washer fluid so quickly and when I went to top it up it was virtually full.
Car was in for an oil change today and asked them to look at it. Mechanic asked if I used the RainX additive. Said there was BMW technical bulletin and it coats the sensor causing it to give a false warning. He emptied the reservoir and refilled with fresh washer fluid - warning is still on and he said it is likely to take a few flushes to clear it.
Thought I would share in case you were contemplating a washer fluid additive - not sure if they all impact the sensor but the RainX product certainly does.
