Glad you got this one sorted out Nick.
We have had terrible rodent problems at my ranch. We found the best thing was to mix concentrated peppermint oil with water in a hand spray bottle and spray it around the engine and cab.
Amazon also has a product for this, but it is much cheaper to just buy the concentrate and mix it.
https://www.amazon.com/Mouse-Rodent-Repellent-Ready-Use/dp/B00316JTQ6
Thanks Charlie, definitely something I should look into for my outbuildings. It has gotten better in the 3 years I've lived here. The previous owner had many large flower beds surrounding all the buildings, I have tilled them all under and planted grass that is kept mowed 2 times a week.