Salt air, humidity and what they do to a used body shell
A car that lived within sight of the sea has aged differently from one that lived inland. This chapter is about where corrosion starts on the coast, how to find it in twenty minutes, and when it is a bargaining point rather than a deal-breaker.
A car underside on ramps with corrosion visible on a chassis rail.
01
Why the coast is harder on metal than kilometres are
Corrosion needs moisture, oxygen and salt, and the air between Cove Rock and Kei Mouth supplies all three for free. Modern galvanising and cavity wax hold it off for a long time, which is exactly why coastal rust tends to appear late and from the inside. By the time a bubble shows through the paint on a wheel arch, the inner arch behind it has usually been thin for a while.
Cars that lived in a closed garage in Vincent fare better than cars that slept under a tree in Nahoon with a cover thrown over them. A cover that traps damp against the paint is worse than no cover at all. Ask where the car was parked at night and watch the seller's face; it is a more useful question than how many owners it has had.
02
The nine places we look, in order
Start underneath with a torch and a bare hand. Front chassis rails behind the wheels, the sill seam where the jacking points sit, the floorpan under the driver's heel, the rear spring seats or beam mounts, the boot floor around the spare well, the tailgate bottom edge and the bottoms of both front doors. On a bakkie add the load-bin seams and the rear of the cab where the bin rubs. Firm pressure with a thumb on sound metal does nothing; on rotten metal it flexes.
Above the floor, look at the top of the windscreen surround and the rear window channel, because blocked drains hold water there, and lift the boot carpet to sniff for damp. A musty boot on the coast is leaking through a light cluster seal or a tail-light gasket, and it will take the rear wiring loom with it in time.
03
What salt does that is not rust
The aircon condenser lives at the front of the car and dies first here. Fine aluminium fins corrode, the condenser weeps, the system loses gas and a well-meaning owner has it regassed twice before anyone looks for the leak. A condenser plus labour runs an indicative R4 000 to R9 000, so a car with a marginal aircon in Eastern Cape humidity is not a car with a small problem.
The other quiet casualty is anything electrical in a wheel arch or under the floor: wheel-speed sensors, handbrake cables, the fuel filler neck, the brake pipes and the reversing-camera connector. Brake pipes matter most. Surface fluff on a steel pipe is normal; a pipe with flaking scale on it needs replacing before the car goes near a long downhill, and a roadworthy tester may well pass it.
04
Repairs, respray and how to spot both
Panel repair is not a scandal. Hidden panel repair is. Look along each flank from the front wheel towards the rear with the light behind you and watch the reflection bend where filler sits. Check the paint on the inner lip of the door shut, the grain on plastic trim that should match the panel beside it, and any overspray on a rubber seal or in the fuel filler recess. Mismatched bonnet and roof mean a car that was repainted, and on the coast that usually means a car that was repaired.
A cheap magnet still works on steel panels, and a paint-thickness gauge is better. We carry one. Readings that sit evenly between 90 and 140 microns across a car and then jump to 400 on one rear quarter tell a story that the seller may genuinely not know, because a lot of these cars have changed hands twice since the repair.
05
What we would still buy, and what we would not
Surface rust on a subframe, a flaking exhaust heat shield, a rust bloom on a brake disc edge, a corroded tow-bar tongue: all normal, all negotiable, all cheap. A soft sill, a flexing floorpan, a rotten rear spring seat or a chassis rail with a hole in it: no. Structural corrosion on a unitary body is a welding and rust-treatment job that very few people finish properly, and when it fails it fails in a crash.
Where it is honestly worth paying more is for the garage-kept car with a dry boot and a clean underside, even if the kilometres are higher. We would take 140 000 careful coastal kilometres with a solid shell over 85 000 on a car with wet carpets any day of the week.
Coastal corrosion works outwards from the inside; paint bubbles mean the panel behind has been thin for a while.
Budget for the aircon condenser on any car that has been regassed more than once near the sea.
Surface rust is a bargaining chip; a soft sill, floorpan or spring seat ends the viewing.
Tell us about the car you are looking at
Send the kilometres, the asking price, the body style and where the car has lived, and we will tell you on the phone whether it is worth an inspection. That conversation is free, and it has talked people out of appointments more than once.