Don't you wish all of the caps under your hood matched? Your oil cap is black and the black expansion tank cap from the Tiguan has been available for awhile. However, it is nearly impossible to find a black washer fluid reservoir cap to tie it all together --- until now. ECS is now offering the black washer cap you have always wanted and has paired it with the popular black expansion tank cap to replace all of your blue caps at once!
The washer fluid cap is not just for looks either. It keeps dirt and debris from entering the washer fluid pump and lines and clogging them up, and keeps the washer fluid from escaping and being wasted. Due to the temperatures reached in the engine bay, the cap can sometimes become brittle and crack, or even just fade out.
Often times, the coolant is not kept under enough pressure to keep it from boiling or expanding too much. The expansion tank cap keeps all the heat and liquid inside the coolant system for maximum efficiency and should be replaced each time major coolant system service is performed.