Modern cars are fitted with plastic covers under the engine bay and along the floor. They improve aerodynamics, cut noise and keep the underbody looking tidy. They also hide one of the most common places for serious rust to develop.
The problem is simple: water, road salt and dirt find their way behind the covers — and stay there. The plastic keeps splash and airflow out, so what gets in dries slowly. Metal that stays damp corrodes, and because everything is hidden behind the panel, nobody sees it happening. The first sign is often a failed NCT component or a repair bill, years after the corrosion started.
What can you do?
- Have the covers off occasionally. At a service or seasonal check, ask for the underbody covers to be removed and the metal behind them inspected.
- Treat the hidden areas. A penetrating anti-corrosion fluid applied behind covers and into seams stops damp metal from becoming rusty metal.
- Protect the exposed underbody too. A proper underbody coating handles the areas taking stone chips and constant spray.
Our cavity protection and underbody protection ranges cover both jobs — and if you are not sure what your car needs, just ask.