Products such as rain-x are supposed to give the windscreen a hydrophobic treatment, so that rain beads off better. Are these compatible with washer fluid additives?
I'm planning to drive to the snow this season. What windscreen washer fluid should I use, to avoid it freezing (and damaging the tubing, etc)? Can I just mix methylated spirits (i.e. methanol) with distilled water, or will it damage the paint unless I use a commercial washer fluid? To preserve the rain-x treatment do I just need to select a detergent-free washer fluid, or is the antifreeze component (e.g. methanol) always going to remove the rain-x anyway?