I don’t know if anyone has heard of this but I had a rat who thought he was going to spend the night on my hot engine, I gave him a headache and I purchased some concentrated peppermint oil, I put half a dozen drops in a spray bottle with half a pint of water and sprayed all my engine bay. It could be luck but no more visitors in my car or my wife’s and it’s cheaper than shot gun cartridges.

And so much quieter too.  DAVE.