Front Chassis Rail Corrosion
SeriousBodywork & RustNB cars can rust badly inside the front chassis rails, sometimes while the outer structure still looks respectable from above.
Est. Repair Cost: £800–£2,500
Reliability GuideCommon Problems with the
Common Problems with the
1998 Mazda MX-5 (NB)
The NB MX-5 launched in the UK with a more modern silhouette and stiffer chassis, though it lost the iconic pop-up headlights. The 1.6 and 1.8 engines proved bulletproof, but structural corrosion became the main concern.
What changed for 1998
- •UK launch of second-generation MX-5
- •Modern silhouette replacing pop-up headlights
- •Stiffer chassis and more powerful engines
- •Glass rear window on Mk2.5 models
Common MOT watch-outs
- !Front chassis rail corrosion
- !Rear sill and wheel arch rust
- !Blocked hood drains causing cabin damp
3
Known Issues
2
Serious
1
Moderate
0
Minor
All Known Issues
Rear Sill and Arch Rust
SeriousBodywork & RustLike the NA, the NB traps moisture around the rear sill sections and arch returns, so rot often starts where it is easy to hide with cosmetic repairs.
Est. Repair Cost: £500–£1,800
Blocked Hood Drains and Cabin Damp
ModerateBodywork & RustWhen the soft-top drains block, water can back up into the cabin and accelerate rust in the sills and floor area.
Est. Repair Cost: £0–£250
Buying Tips for 1998 Mazda MX-5 (NB)
- ✓Inspect the front chassis rails as carefully as the rear sills; this is the hidden structural failure point on many NB cars.
- ✓Check the hood drains and footwells for damp, especially on cars that live outside.
- ✓Rust-free cars with strong evidence of preventative undersealing are worth a premium.