Bonnet problems might seem like a minor inconvenience, but when it comes to the MOT test, they’re more important than most drivers realise.
If your bonnet doesn’t close securely, or the retaining mechanisms are deteriorated or ineffective, it could cause your car to fail its
MOT.
In this guide, we’ll explore what counts as a bonnet defect, how MOT testers assess it, and what you can do to avoid a bonnet-related failure on test day.
Why Bonnet Issues Matter
The bonnet (or hood) of your car protects the engine and other critical components – but it also plays a role in safety and driver visibility.
If a bonnet were to fly open while driving, it could block your view of the road entirely – creating a major hazard not only for you, but for other road users too.
That’s why bonnet catches and retaining devices are checked under the
“Visibility” section (Section 3) of the MOT inspection manual.
If the bonnet can’t be securely closed, or is likely to open on its own, it’s considered a serious safety defect.
When Will Bonnet Issues Cause an MOT Fail?
MOT testers assess the primary bonnet catch only – this is the main device that keeps the bonnet fully shut.
Secondary safety catches (the ones that stop the bonnet flying fully open) are not part of the official test, but a defective one may still be noted as an advisory.
Here’s what testers will check – and how each issue is categorised:
1. Bonnet Cannot Be Safely Secured
Result: Major defect & MOT fail
If the bonnet doesn’t shut properly or the catch doesn’t engage fully, it will result in an immediate fail. Testers will check this by closing the bonnet and lifting it slightly from the front to see if it stays firmly shut.
2. Bonnet Seriously at Risk of Opening Inadvertently
Result: Dangerous defect & MOT fail
This is the most severe case. If the bonnet is judged to be on the verge of flying open while the car is in motion, the defect is classed as dangerous – and the vehicle cannot be driven away until repaired.
3. Primary Retaining Device is Deteriorated or Insecure
Result: Major defect & MOT fail
Rust, broken components, or excessive wear to the latch or slam panel fittings can make the retaining device ineffective. Even if the bonnet seems to stay shut, if the components are clearly failing, the tester will reject it.
4. Bonnet Cannot Be Opened to Access Other Testable Items
Result: Test refused or abandoned
If the tester cannot open the bonnet at all, they may refuse to conduct the MOT. That’s because they need access to under-bonnet components such as fluid levels, brake mechanisms, or emissions systems. If access is blocked, the test cannot proceed.
What About Older Bonnet Designs?
Some older vehicles use alternative bonnet securing systems – such as leather straps or ‘R’ pins – especially on classic cars or racing models. The rules still apply, but the checks will vary depending on the design.
In these cases, testers are instructed to assess the retaining mechanism based on its ability to securely hold the bonnet shut, even if it doesn’t use modern latches. If the system is secure and effective, it should pass. If not, it may still be marked as a major or dangerous defect.
Secondary Bonnet Catches – Are They Included?
No – secondary bonnet catches are not part of the MOT inspection. These are the backup devices that engage if the primary catch fails.
That said, if the secondary catch is clearly damaged or non-functional, the tester may advise the vehicle owner to get it fixed.
While it won’t trigger a fail on its own, it's still an important safety feature.
How to Check Your Bonnet Before an MOT
You don’t need special tools or skills to spot most bonnet issues. Before test day, try the following:
- Open and close the bonnet fully – listen and feel for a solid click to ensure it latches securely.
- Pull up gently on the front edge once it’s closed – if it lifts, wobbles, or feels loose, the catch may not be holding properly.
- Inspect the catch mechanism itself – look for signs of rust, excessive wear, or any broken or missing parts.
- Check both sides on vehicles with twin catches – make sure each catch engages properly and holds the bonnet down firmly.
In many cases, a quick adjustment or low-cost part replacement is all that’s needed to avoid a fail.
Final Thoughts
Bonnet issues may seem cosmetic – but if the main catch fails or the bonnet can’t be secured, your car could receive a major or even dangerous
MOT defect.
MOT testers follow strict guidance when inspecting primary retaining devices. If your bonnet is insecure, severely worn, or impossible to open for further checks, your vehicle won’t pass the test.
Thankfully, bonnet problems are usually easy to spot and fix in advance. Give it a quick check before MOT day – and if in doubt, ask your garage to inspect the latch mechanism.
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FAQs:
How much does it typically cost to fix a bonnet catch before an MOT?
In most cases, repairing or replacing a bonnet catch is one of the more affordable pre-MOT fixes. A straightforward latch replacement or cable adjustment at a garage is relatively inexpensive, and the parts themselves are generally low cost. If the slam panel — the metal section the catch clips into — has corroded or become misaligned, the repair can be more involved, but it is still typically a modest job compared to other MOT-related work.
Can a bonnet that has been in an accident still pass an MOT?
It can, provided the primary catch mechanism still functions correctly and the bonnet closes securely without risk of opening while driving. However, accident damage often causes misalignment between the bonnet and the slam panel, which can prevent the latch from engaging properly. If the bonnet has been involved in a collision, it is worth having the catch mechanism checked and adjusted before presenting the vehicle for its test.
Will a bonnet that rattles while driving fail an MOT?
Not necessarily, but a rattle can be a sign that the bonnet is not sitting securely or that the catch is worn and not holding the panel as firmly as it should. If the tester finds that the primary retaining device is deteriorated or that the bonnet has excessive movement when checked, it may be recorded as a major defect. It is worth investigating any rattling before your test to be on the safe side.
