Of all the things to fail your MOT on, windscreen issues are among the easiest to overlook. But make no mistake; your car can fail its MOT if there’s a problem with the front window, so it’s an area you’ll want to add to your pre-test checklist.

As part of our series exploring potential MOT failures, we’re shining a light on windscreens and the problems that can result in a dreaded red cross on your test certificate. We’ll be answering common questions to help you get to grips with how and why windscreens can lead to a failed MOT, and the issues to be aware of.

Navigate using the links below or read on for our full FAQ guide to windscreen MOT failures.

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Can a cracked windscreen fail an MOT?

Your car might fail its MOT if there’s a crack on the windscreen, but it’s not an automatic failure. It all depends on the size of the crack and where it’s located.

If you have a big crack that’s over 40mm in diameter, your car is guaranteed to fail, so you should have it fixed before turning up at the test centre. Some cracks can be repaired with special resins, but if the structure of the glass has been compromised, you’ll be looking at a complete windscreen replacement.

In cases where the crack is below 40mm, it gets a bit more complicated. The damage will be assessed by where it’s located on the windscreen in relation to the driver’s eye line.

The diagram above demonstrates the pass and fail zones. Any crack within Zone A means a failure; a crack in Zone B will most likely mean a pass with an advisory note to have the crack fixed.

Is your car’s windscreen damaged? Find out what to do in our expert guide.

Is a chipped windscreen an MOT failure?

Not necessarily but it could happen. As with cracks, it depends on the size of the chip and where the damage is located.

Since chips tend to be much smaller than cracks, you’re unlikely to fall within the +40mm automatic fail category. In fact, since the chip may be smaller than 10mm, your car may not even fail if the damage is in Zone A.

At this point, it’s down to the examiner’s discretion. If they think the chip could impair visibility within the driver’s eye line, they may endorse an MOT failure. If it’s only minor damage and unlikely to cause any problems, they may mark it down as an advisory and recommend a repair.

Either way, it’s best to repair chips before they get any worse. All it takes is one cold night or one pothole strike for that minor chip to turn into a big crack, so don’t leave things to chance.

Are windscreen wipers part of MOT?

They certainly are! If your windscreen wipers don’t clear the windscreen as they should, you could fail your MOT.

The front wipers should remove moisture and dirt to maintain full visibility of the road ahead. If they’re damaged or worn out, they might struggle to clear the screen or leave streaks and residue that further compromise visibility.

A week or two ahead of your MOT, check the condition of your wipers, particularly the rubber wiper blade. Is it smooth, supple, and free from abrasion? Or does it have cracks and splits that mean it’s not sluicing water and dirt away as it should?

Windscreen wiper blades are easy to replace yourself, which is why we recommend checking them a week before your test, so you have time to order and fit replacements. Remember, if a test examiner suspects your wipers are impairing visibility, you could fail your test – and all for a small issue that’s easy to fix.

Will a faulty rear wiper fail an MOT?

You can’t fail your MOT for a faulty or worn rear wiper since they aren’t required by law. Plenty of cars don’t have a rear windscreen wiper, so it’s not something that’s checked on the MOT.

Still, it doesn’t hurt to replace your rear wiper blade often to maintain maximum visibility out of the rear window. If you neglect to replace the rubber blade regularly, it could wear out to the point where the metal wiper arm scratches the glass – something that could permanently affect rearward visibility, not to mention impact your car’s future resale value.

Will I fail my MOT if I don’t have any screen wash?

Yes, that’s a guaranteed failure so always top up ahead of your test. If you don’t have screen wash, you can’t clear your windscreen, and that’s dangerous according to the DVLA.

Screen wash is an easy thing to overlook before your MOT but getting into the routine of topping up regularly should help you to avoid any mishaps. Read our screen wash FAQs for more need-to-know advice and tips on choosing the right screen wash for your needs.

Key Takeaways

  • You can fail your MOT for a cracked windscreen, but it does depend on the size of the damage and where it’s located.
  • A chipped windscreen might result in MOT failure if it’s clearly causing visibility problems, but this is at the test examiner’s discretion.
  • Windscreen wipers are included in the MOT, so check yours a week before the test to give yourself enough time to fit a replacement if necessary.
  • You can’t fail your MOT for a faulty rear windscreen wiper, and it’s not included as part of a standard test.
  • You will fail your MOT if you don’t have screen wash, so always top up before driving to the test centre.
  • Tap here for a full checklist and advice on preparing for your MOT

Enjoyed this guide and found it useful? We’ve dozens of similar resources to help you navigate the often-confusing world of car maintenance and ownership. Visit the Prestone help and advice centre for more.