What is a Washer Fluid Top-Up?
A clear windscreen is an MOT requirement and a safety essential.
Simplified animation — not to scale.
In plain English
The washer fluid reservoir is the plastic tank that feeds water to your windscreen washer jets (and often rear screen and headlights too). It's easy to spot under the bonnet — look for a cap with a blue washer-spray symbol on it (an icon of a windscreen with dotted lines). Running out is one of the most common MOT advisories.
"Like keeping water in a water pistol — except it's the only thing standing between you and a smear of dead flies at 70mph."
How it works
Open the bonnet and find the cap with the blue washer symbol — not the coolant cap, which is normally yellow or black with a warning triangle. Unscrew or flip it open. Pour washer fluid (concentrate diluted as per the bottle, or pre-mixed) straight in until the level reaches MAX. Use proper screen wash — not plain water — because it includes detergent to cut through bug splatter and, crucially, antifreeze to stop the system freezing in winter. Refit the cap firmly. Test the jets by pulling the wiper stalk towards you.
Signs of trouble
- ⚠Wipers smear instead of clearing the screen
- ⚠No spray when you pull the washer stalk
- ⚠Visible warning on the dash about low washer fluid
- ⚠Frozen jets in winter (sign you've been using plain water)
£2–£8
Always get a written quote. Prices vary by car, region, and parts brand.