Can a Windscreen Chip Lead to MOT Failure?
Yes, a windscreen chip can absolutely lead to your vehicle failing its MOT test. The critical consideration for the MOT tester is not just the presence of a chip, but its size and, more importantly, its position on the windscreen. The Driver and Vehicle Standards Agency (DVSA) has clear guidelines on what constitutes a dangerous defect for windscreens, and chips falling within specific zones are guaranteed to result in a failure.
- Windscreen chips can cause MOT failure if they obstruct the driver's view.
- Location is key: damage within the driver's direct line of sight is unacceptable.
- Size and severity of the chip or crack determine if it's a fail.
- Minor chips outside critical areas might pass, but repairs are recommended.
The MOT test is fundamentally about ensuring vehicles are safe and roadworthy. A damaged windscreen can compromise structural integrity and, crucially, impair a driver's visibility, which is paramount for safe driving. Therefore, the MOT test includes a thorough inspection of the windscreen for any defects that could pose a risk. It’s not just about aesthetics; it's about safety.
Many drivers believe any chip means an automatic failure, but this isn't always the case. However, relying on a minor chip being overlooked is a risky gamble. Understanding the specific rules will help you prepare for your MOT and know when action is necessary.
Understanding MOT Rules for Windscreens
What exactly constitutes an MOT failure regarding windscreens? The rules are designed to ensure the driver's view of the road is unobstructed. The DVSA specifies 'swept areas' of the windscreen – the areas cleared by the windscreen wipers. Any damage within these swept areas is scrutinised closely.
Specifically, the regulations state that the windscreen will fail if there is damage within the area swept by the driver's side wiper, which is approximately 8mm to the left of the steering wheel and 6mm above the steering wheel, extending upwards and to the right across the windscreen. Beyond this immediate critical zone, there are further guidelines.
The 'Critical' Windscreen Zone
The most critical area is directly in front of the driver. Damage that obstructs the driver's view is the primary concern. This includes chips or cracks that are 10mm or larger in the driver's direct line of sight. This zone extends across the breadth of the driver's normal field of vision.
Cracked Windscreens and MOT Tests
A crack is generally treated more seriously than a chip, especially if it extends. A crack that is 150mm or longer, or any crack that has splintered into the windscreen's layers, will likely result in an MOT failure. The integrity of the glass is compromised, and the risk of further damage or shattering increases.
The MOT tester will be looking for any damage that could distort the driver's view of the road or adjacent traffic. This includes chips that create significant optical distortion or spiderweb cracks. The test is not just about the size of the chip but also its potential to obscure vision or weaken the glass structure.
The MOT test prioritises your ability to see the road clearly and safely.
It's worth noting that while the MOT test focuses on safety-critical defects, it's always prudent to address minor windscreen damage sooner rather than later. A small chip can spread due to temperature changes or vibrations, potentially turning a minor repair into a costly windscreen replacement.
When Does a Windscreen Chip Cause a Failure?
So, when is that small chip a big problem for your MOT? The DVSA provides specific measurements and locations that determine a pass or fail. The key is understanding these criteria before your test.
Size Matters: The 10mm Rule
If a chip is located anywhere within the area swept by the driver's side wiper, and it is larger than 10mm, it will result in an MOT failure. This is the most common scenario where a chip causes a fail. The tester will use a device to check the size and shape of the chip against the regulations.
Location is Paramount: The Driver's Line of Sight
Even if a chip is smaller than 10mm, if it is directly in the driver's line of sight, it can still cause a failure. The DVSA defines this zone as the area that the driver looks through to see the road ahead. This typically means any chip or crack directly in front of the driver, below the steering wheel and extending upwards. Damage here is considered a safety hazard because it can obscure vision, especially in poor light or weather conditions.
The 40mm Rule for Other Damage
For damage that is not in the driver's direct line of sight, but still within the swept area, the maximum size allowed is 40mm. This includes chips or cracks that are more towards the passenger side or higher up the windscreen, as long as they don't impede the driver's primary view. However, if this larger damage causes any distortion or affects the windscreen's structural integrity, it could still be a fail.
When a tester inspects your windscreen, they are looking for any defect that could obscure the driver's vision or compromise the windscreen's strength. A chip that is close to an edge or near another defect might also be problematic. It's the combination of size, location, and potential impact on visibility and structural integrity that dictates the outcome.
Inspect your windscreen thoroughly before your MOT appointment, paying close attention to the driver's side and the area swept by the wipers. Early detection can save you an unexpected fail.
If you have multiple chips, the tester will assess them collectively. Even several small chips outside the critical zone could, in some instances, be deemed a collective hazard if they significantly weaken the glass. Always err on the side of caution.
What to Do About a Windscreen Chip
Discovering a chip in your windscreen can be concerning, especially with an MOT looming. Fortunately, many windscreen chips are repairable, often saving you the cost and inconvenience of a full replacement. Understanding your options is key to keeping your vehicle roadworthy.
Repair vs. Replacement: When is a Repair Viable?
A chip is generally repairable if it is smaller than a 10p coin and is not directly in the driver's line of sight. The resin used to fill the chip bonds the glass together, preventing it from spreading and restoring structural integrity. Many vehicle insurance policies cover windscreen repairs completely, meaning you might not even have to pay a excess. It's always worth checking with your insurer.
If the damage is extensive, such as a long crack or multiple chips, or if the chip is in a location that would cause an MOT failure, replacement is usually the only option. Specialist windscreen repair services can assess the damage and advise on the best course of action.
Choosing a Windscreen Repair Service
When seeking a repair, look for reputable services that adhere to industry standards. They should use high-quality resins and employ trained technicians. A good repair will be virtually invisible and will restore the windscreen's strength. Always ask about their guarantee on the repair.
Getting a chip repaired promptly is crucial. Leaving it can allow dirt and moisture to seep in, making a successful repair more difficult and increasing the likelihood of the chip spreading. A small chip that costs relatively little to repair could otherwise lead to the expense of a new windscreen.
If you are unsure whether your windscreen damage will pass the MOT, it is advisable to consult with an MOT test centre or a professional windscreen repair specialist beforehand. They can provide an expert opinion based on the specific defect and current MOT guidelines. Early intervention is your best strategy.
Preparing for Your MOT: Windscreen Checklist
As your MOT date approaches, a systematic check of your vehicle can help avoid last-minute surprises. Your windscreen is a vital component, and its condition can directly impact your MOT result. Here’s a checklist to ensure you're prepared.
Visibility Check
Start by sitting in the driver's seat and looking through the windscreen. Can you see clearly without any distortion from chips, cracks, or scratches? Pay attention to the area directly in front of you, as this is the most critical zone for the MOT test. Ensure your wipers are also in good condition and effectively clear the screen.
Chip and Crack Inspection
Walk around your vehicle and inspect the entire windscreen. Look for any chips, no matter how small, and any cracks. Note their size and location. Remember the MOT rules: chips larger than 10mm in the driver's swept area, or any damage in the driver's direct line of sight that causes distortion, will likely cause failure. Cracks over 150mm are also a fail.
Cleaning for Clarity
Ensure your windscreen is thoroughly clean, both inside and out. Dirt, grime, and smudges can obscure vision and make existing minor chips appear more significant. A clean windscreen allows the MOT tester to clearly see any existing damage, and it demonstrates good vehicle maintenance.
Clean your headlights and taillights too, as obscured lights are another common MOT fail point, and it’s a simple task to do yourself.
By taking these steps, you can proactively identify any potential issues with your windscreen before they become a reason for MOT failure. Addressing minor chips early through repair can save you time, money, and the hassle of re-testing.