How to approach someone to buy a car?

I saw this nice 89 honda hatch down the street from where I live. It's always in the driveway and we'll maintained. The owner doesn't seem to drive it like a daily. Maybe once every 2 months. I want to approach him to ask if he is willing to sell his car. I do not know him and don't even know knows me. How should I approach this? Walk up to his house and ask if he's going to sell it? He's a complete stranger don't forget and I have no clue if it's his or his dads or his, he is around 20 something and the dad is around 50 ish.

Just knock & ask. If there's no for sale sign on it, they probably don't want to sell it but you can ask. If its nice, they won't sell it cheap.

You can also leave a note on it asking them to call you if they are interested in selling it.

I had a man ask me if I wanted to sell my car in the walgreens parking lot.

I said "no thank you". He needed a car for his kid, mine is a cheap one and it was a reasonable question given I'm 50 and can afford a nicer car.

It took him 2 seconds to ask and me 2 seconds to decline. No big deal.

A guy down the road had a motorbike I would have loved to buy. I just walked up and asked him if he was likely to sell, he said no, end of story.
But if you don't ask, you won't have a chance of buying it.