Taha
There are two school of thoughts as far as using oil or diesel while service is concerned,
One says that it is useful and prevents rust.
While other says that it damages rubber parts (many mechanics also say so)
I also agree with the second opinion, so lets decide if you are going to continue to use clean water only and no oil. Then you can ask your denter to paste asphalt on the rusted areas (it is commonly known as compund, which i think is refined asphalt) if oil is used on this material it will come off if you use only water it will protect the areas and wont come off.
Xulfiqar sb advised me to use some rubber spray (coating) for under body but i could not find it in gujranwala, no body even knows about it.
Lets see what does other members say about it.
In fact i would accept that it is the worst thing (car) in my experience. I owned a cuore 02 model and it was rust free. so i am also sort of confused about the situation.