Do you mean you don't agree with my interpretation hightlighted in red below? What's your interpretation then?
There's a car engine sitting on the floor of my garage and I would say:
1. The car engine is still in good condition though it looks old.
If there's a car instead of just a car engine in my garage, to emphasize that the engine belongs to the car, I would say:
2. The car's engine is still in good condition though it looks older than the car itself.
If my interpretation is correct, #1 shouldn't take the possive form because it misleads the listener to think there's a car in the garage and the speaker is refering to the engine in the car.