One of the basic rules of open desert driving is to ONLY drive during the day. Night driving easily disorientes AND is harder to tell where the packed sand patches are, you end up plowing into the loose stuff and getting stuck. As for the heating issue, why didnt they just remove the hood?
Loose sand is actually going to be less a problem at night. The heat from the day will dry out the sand. At night with the moisture, the sand tenda to stays firmer. Remember this is Chile not the Sahara. Mountains and the ocean aren't that far away. They run the Dakar through there and it's not limited to the day. THe conditions change drastically throughout the day. They usually leave in the early morning and by mid-afternoon the sand starts to turn into feshfesh.
The reason they didn't remove the hood was that they have limited tools. I doubt they have a ratchet and the torx bits.
Also, I think the reason for the diesel sound is that this isn't a US show. They have sold the show world wide. Most other countries would relate more with the diesel. On their FB site they are promoting the show a lot in other countries.
