For those who don't have a car jacket, I like a product called Fresh Cab. It's a combination of herbal stuff in a little sack that smells great but mice hate it. It's available at Tractor Supply stores here. They last about a month before you need to change them. If you can't smell them anymore, change them.
I also put plastic sandwich bags with rubber bands over the tailpipe ends and the air cleaner snorkel. My garage is not mouse proof so I have to take extra precautions.
Verne