Transparent / Tnsichtbar Auto

[CNPjesus]

Hello good evening, first I want to say that I use a translator, so I try to write the words to explain my problem:

I'm starting in the modeling world and I'm doing some cars from my country (Spain). So far I have managed to make the car I want, but the problem I have is that when you're a bit away from the car looks invisible, or transparent.

This problem does not happen in other vehicles, so you need something to do.

could you help me? With what they can, indications, videos, whatever.

Attached a few pictures so that the problem is understood

Thanks in advance