Punjabi dogs here in Chandigarh have a habit of emptying their large intestine contents (aka sh!t) in front of our gates. They are very precise in doing this. What i have learnt is that they do not like to come near phenyl water. So every other night we put 4-5 teaspoonful phenyl in half a litre of water and pour it in front of our gate. May be you can try this by pouring water on ground all around your car. I am not sure if its god to pour phenyl water on car. I bet that would work 100% but what about the effect on car paint and also one will have to wash car in morning to avoid smell. So only option is to pour phenyl water on the ground around the car.