first thing is that mechanics dont use olx.
now regarding starting a business it need a lot of homework to be done ..
would u be present on the shop ? if not do u have someone trust worthy to be there ?
i am not mechanic nor do i have any experience .. but do discuss it with some mechanics whom u know .. they may provide u info ..
or better u rent ur shop ..
else there will be more gaplaz .. in case u are not personally present there ..
and also look if u have enough customers around .. else u wont be able to do business.
my 2 cents ..