The washer reservoir cap is necessary for the vehicle because it seals the washer fluid in the washer reservoir.
Washer reservoir cap importanceThe washer reservoir cap is a component that is typically composed of plastic and is meant to fit perfectly. The cap is designed to fit as best as possible to help secure the washer fluid and prevent any leaks. The windshield washer reservoir cap must remain in good working order to maintain proper fluid level.
Common problems with a faulty washer reservoir capA defective reservoir cap can lead to leaking, a loose fit, or wearing out.