My Screen washer flow reduced to a pathetic dribble over time and the fluid coming from them smelled like rotten eggs so braving the snow this morning I removed the tank from the LH inner wing. Sure enough the pump filter was blocked with a jelly like substance and the bottom inch or two of the tank contained a foul smelling watery gunge. The headlight washers were working fine as that pump is higher up the tank away from the gunge. A good clean and flush out and all is fine now but I wonder what would cause the water to stagnate? I know our cars are getting on a bit so the fluid could've been in there a while.
Maybe an idea would be to run the tank empty and just fill it with fresh water for the summer months to keep it clean, or maybe I use the wrong fluid.
Any ideas?
Cheers
Pete

 

you probably had rainx or something in there. happened to me as well

 

Doesen't Rainx have a solvent, denatured alcohol in it?

 

Any fluid with alcohol antifreeze in it will prevent biological growth like that.