I understand what you are saying, however I think it odd the way you say it.
“It doesn’t grow towards the sun, as much as it turns towards the sun; because where the sun is changes during the day.”
That is like saying that if I am trying to get my sailboat back to port, and I have to tack to keep on course, I’m not really heading to port.
Heliotropism isn't the plant growing towards the Sun (which direction is towards the Sun?); it is the plant turning its leaves towards the Sun.
Even if the plant isn't growing, they will still display heliotropism; facing East in the morning and West in the evening.
As far as a vine growing over a car, that is what vines do. They grow over things and “rob” them of their sunlight; luckily for the car it doesn't need sunlight.