Yes, I remember your March Thread entitled RATS!, and the associated video. Great job on that, and I'm very glad it is working well for you. What I am exploring here is the possibility that a certain spectrum of bright white light might be an effective repellent ala carte, as long as there are no shadow areas in the engine bay. The rope light makes it easy to keep all the hidden corners of the engine bay flooded with 5000 Kelvin light.
Stop those rodents immediately. I didn't know as the motor home was parked in a fenced in yard. We loaded to go and the motor home wouldn't move. Rodents had removed 13 different sections of wires and stuffed them along with other debris under the air breather on the 454 engine. They attacked wires from the nose of the RV to the rear. I spliced the 13 wires and got her going.
I just paid $1239 to have the fuel line replaced on my F-150. Squirrels or rats chewed a hole in it so I narrowly escaped a fire. Ford wrapped the part they like to chew on with some kind of mesh after replacing the line. I placed some large repellent balls in the motor compartment. hopefully this will help. The mechanic said there are some parts that attract rodents and he had repaired several.
A friend suggested moth balls in the engine compartment, which worked but stunk. Now, courtesy of the same friend, I spray WD-40 throughout the area to keep the little blighters out. I keep the can in a nook under the hood and probably respray 4 times a year or so. There's no noticeable smell either. I understand they also hate the smell of peppermint, but haven't tried any peppermint oil.