Ford Fiesta Mk6 1.25 82bhp — Sill and Rear Arch Corrosion
The Mk6 Fiesta is now 10+ years old and sill corrosion is increasingly common on UK examples. Bubbling paint along the sill seam and rear arch lip is a typical MOT failure point.
Severity
ModerateDIY Difficulty
Hard
Est. Cost
£300–£1500
OBD Codes
None
Rust
Typical layout and location for the Rust assembly.
Symptoms
- Bubbling or blistering paint on sill seams
- Visible rust at rear wheel arch lip
- MOT failure for corrosion to structural sill
- Paint flaking around door aperture lower edges
Root Cause
Road salt and moisture penetrate the factory seam sealer on the sill box sections. Once rust starts inside the sill, it progresses quickly and is invisible until it breaks through the paint. Cars parked outside year-round deteriorate faster.
How To Fix
- Inspect sills with a torch — poke suspected areas with a screwdriver (not a magnet)
- Light surface rust: treat with rust converter, seal with cavity wax and body sealer
- Structural rust: requires panel replacement by a bodywork specialist
- Annual Waxoyl or Dinitrol cavity injection significantly slows progression
- Budget £300-1,500 depending on severity
Estimated Repair Costs
| Repair Option | Est. Cost (GBP) |
|---|---|
| DIY (parts only) | £120–£600 |
| Independent Garage | £300–£1500 |
| Main Dealership | £480–£2400 |
Other Faults on This Variant
Front Wheel Bearing Failure
ModerateFront wheel bearing wear is extremely common on the Mk6 Fiesta. Most examples will need at least one bearing replaced between 60,000 and 100,000 miles.
Power Steering Pump Failure
ModerateThe hydraulic power steering pump on the Mk6 Fiesta fails with age and mileage, making the steering very heavy — especially at low speeds and when parking.
Ignition Coil Pack Failure
ModerateThe single coil pack block fails, causing a 2-cylinder misfire.
Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.