Hoe to keep animals from making a nest under the hood of your car
Sadly, you can’t prevent this. Some people use mothballs placed under the hood - not on HOT places! - to some success. There are sprays available to deter critters from nesting. Some work better than others. Try a few, see what works for your critters.
I had this. I just cleaned it out regularly; they gave up eventually. Some gnaw at the wires, so check those for damage. I bet leaving the hood up would work, not that you would want to do that. A cat may go after them.
We use this product in a pole barn where classic vehicles, hot rods, motorcycles, boats, etc… are stored.
We have yet to see any signs of critters in the building.