Kun Hyundai — Regarding my i10 car fuel tank rusting trouble

Address:

Pondicherry, Puducherry

I purchased a i 10 new 1.1 car from chennai in 2010 december. The vehicle is really good, i am satisfied with its performance. But yesterday i left the car f or servicing at kun hyundai pondy. During that time they informed that the fuel tank gets rusted and needs to be replaced. i am shocked. I am a regular usage, own driving type car owner and fill petrol in selective bunks only. So i get panic. How it happens? Is there no rust proof coating? Is there no sensors to sense rusting level? does there is no method to avoid rusting? Can we now clean the tank, apply rust proof coat and re-use? The above doubts are to be clarified.