If you’ve been checking MOT histories lately, you may have noticed a sudden increase in corrosion-related advisories and failures across a wide range of vehicles. Many cars that previously had clean MOT records are now being flagged for structural rust, and in some cases, they’re failing outright. But why is this happening, and what does it mean for car owners and dealers?
What’s Behind the Increase in Corrosion Failures?
Stricter MOT Testing Standards
In recent years, MOT testers have been under increased scrutiny, and many are now flagging even normal levels of surface corrosion that were previously considered routine wear and tear. This means that even a well-maintained car could suddenly receive advisories for light rust that has no impact on its safety or structural integrity.
It’s important to understand that corrosion on the underside of a used vehicle is totally normal—after all, the chassis, suspension, and exhaust components are made of metal and exposed to the elements year-round. The real concern is excessive corrosion that compromises key structural areas, such as suspension mounting points, seatbelt anchorages, and subframes. If an MOT advisory or failure mentions surface corrosion only, it’s not an urgent issue. However, if it states excessive corrosion affecting structural components, that’s when repairs may be necessary.
Changes in MOT Testing Stations
Some MOT stations have changed hands or brought in new testers who are stricter than their predecessors. This means that a vehicle that passed comfortably last year with no advisories might now have multiple corrosion warnings, simply due to a different tester’s judgment.
What Does This Mean for Car Owners and Dealers?
- For Private Car Owners: If your car has suddenly been flagged for corrosion, don’t panic. Only excessive corrosion near structural areas is a real issue—light rust on suspension arms, exhausts, and floor panels is completely normal for any used vehicle. If you’re unsure, get a second opinion from a trusted garage before agreeing to costly repairs.
- For Used Car Dealers: The rise in corrosion-related MOT advisories means more caution is needed when buying stock. A car with no history of rust advisories might suddenly get flagged, affecting its resale value. However, just because an MOT mentions corrosion doesn’t mean the car is unroadworthy—only excessive corrosion is a cause for concern. To provide peace of mind for buyers, we apply winter protection to most of our older cars during the preparation process. This helps prevent further rust development and ensures our vehicles are well-protected from the elements.
- For Buyers of Cheap First Cars: If you’re shopping for a budget car (under £3,000), expect some level of corrosion advisories. This is normal and does not automatically mean the car is unsafe. Always check where the corrosion is located—if it’s on non-structural parts like exhaust brackets or subframes, it’s rarely a major issue.
Conclusion
The sudden rise in corrosion advisories and failures is largely due to stricter testing and individual tester interpretation rather than a sudden epidemic of rusty cars. A corrosion advisory does not mean a car is unsafe—only excessive rust in key structural areas is a real concern.
For car owners, understanding the difference between surface rust and serious corrosion can save unnecessary worry and expense. For those in the trade, ensuring vehicles are properly protected before resale can help prevent future advisories.
If you’ve noticed an increase in corrosion-related MOT failures, share your experiences—have you had cars flagged for rust that was previously overlooked?