Since the vehicle was not sold voetstoots according to you and a latent defect became apparent after the sale of the vehicle, you would have the following remedies:
1. You can sue for the cancellation of the agreement. In this instance, you would be able to give the article back and receive your money back. You would lose this remedy if you do not inform the seller of your intention to cancel the agreement within a reasonable time. What is reasonable will depend on the facts of the matter and will not be the same for every instance. You would also lose the remedy if you displayed an intention to keep the product after you learned of the defect.
You would have to prove that the defect existed at the time of purchase, that it is a latent defect, that you would not have purchased it if you knew of the defect and that you cannot use or partially cannot use the product for what it was intended for.
2. You can sue for a reduction in price. In this instance, you get some of your money back, but you keep the vehicle. The amount you would get back is generally what it would cost you to fix it, alternatively, the amount that the defect has reduced in price because of the defect, whichever is the lesser amount.
You would have to prove the same as above, except that you would not have bought the vehicle, but for the defect. In addition, you would also have to prove the amounts as set out above.