Few things in life are as annoying as driving down the road in the rain with the accompanying squeak of windscreen wipers. You can't escape it and you don't know why they are squeaking. Taking time to discover and fix the source of the squeak can not only save you from this annoyance, but may also save your wipers or your windscreen glass.
Wipers begin to degrade the day they are installed and have a relatively short lifespan. Even more expensive wipers only last on average for six to nine months. In places where it doesn't rain much, the rubber on the wiper blade can become dry and brittle from disuse. In wetter regions, blades wear out from constant use. Both overused and underused wiper blades can cause squeaking on a windshield because the rubber is not forming a tight seal against the glass.
Build-up of dirt or wax on the wiper blades or windscreen can also cause squeaking. Contaminants can scrape against glass and loosen the seal between the window and the wiper. Since windscreen wipers work like a squeegee, they work best when both the glass and the rubber are clean. Wax build-up on glass can make wipers skip and squeal.
Even tiny nicks or cuts in a rubber wiper blade can cause squeaking. They can also severely scratch window glass, leaving the kind of damage on windscreens that can only be fixed by replacing the glass. Never run windscreen wipers over ice, or debris like leaves, as that can tear the rubber on the wipers.
The wiper assembly can also create squeaky problems if the frame is bent or damaged. The spring that holds the arm needs to keep the tension tight enough between the blade and window so that air does not get between them to cause squeaking or skipping. Sometimes the valve assembly in the wiper motor needs to be lubricated. The parts are small and difficult to access so it's often best to leave this to a qualified mechanic.
The best defence is a good offence when it comes to squeaky windscreen wipers. Keep glass clean and free of debris. Wash your windows every time you fill up with fuel and run a cloth over the wiper blade to keep it clean. Special lubricants used on wiper blades can help keep the rubber soft and pliant. Never run wipers over frosted or icy glass. Last, replace your windscreen wipers every six months or as soon as you notice a problem that can't be fixed.