Structure advisory
MOT Corrosion Advisory Cost and Walk Away Signs
Corrosion is the advisory that most often justifies walking away, especially on cheap cars where welding can exceed the car value.
Typical UK cost
GBP 150-500 for small welding repairs, GBP 800+ for structural or repeated corrosion
Buyer risk
Walk-away risk
Negotiation note
Structural corrosion should be priced as a major risk, not a small cosmetic defect.
MOT wording this covers
- Corrosion
- Vehicle structure corroded
- Sub-frame corroded but not seriously weakened
What it means
The tester has seen rust on a body, chassis, subframe or prescribed area. The key question is whether it is cosmetic surface rust or structural corrosion near safety-critical mounts.
Is it safe to drive?
A single advisory may be monitorable, but corrosion near suspension, seatbelt, braking or steering mounts should be treated as serious.
Should you buy a car with this advisory?
Walk away from cheap cars with repeated structural corrosion unless you are budgeting for welding. Fresh underseal over rusty areas is a warning sign.
Checks at a viewing
- Check MOT history for corrosion advisories becoming more detailed over time.
- Inspect sills, wheel arches, subframes, boot floor and suspension mounting areas.
- Be suspicious of fresh underseal, wet carpets or recently painted underside sections.
Garage checks
- Ask for a ramp inspection before purchase.
- Ask whether corrosion is within a prescribed area for MOT purposes.
Check the full MOT history
Repeated advisories matter more than one isolated note. Enter the registration to check the vehicle history and model failure pattern.
Frequently Asked Questions
How much does a corrosion advisory advisory cost to fix?
A typical UK repair range is GBP 150-500 for small welding repairs, GBP 800+ for structural or repeated corrosion. The final bill depends on the car, access to the part, labour rate and whether related parts also need replacing.
Is corrosion advisory a serious MOT advisory?
A single advisory may be monitorable, but corrosion near suspension, seatbelt, braking or steering mounts should be treated as serious.
Should I buy a used car with corrosion advisory on the MOT history?
Walk away from cheap cars with repeated structural corrosion unless you are budgeting for welding. Fresh underseal over rusty areas is a warning sign.
What should I check before buying a car with this advisory?
Check MOT history for corrosion advisories becoming more detailed over time. Inspect sills, wheel arches, subframes, boot floor and suspension mounting areas. Be suspicious of fresh underseal, wet carpets or recently painted underside sections.