How much would it cost you to rent a car for the few times you'd need one? Compare that to the cost of repairing a car you rarely use, and see if it's worth it.
Very simple, just do the math. You can:
1. fix car, but will still need work down the road
2. scrap/sell car and rent one when needed; keep insurance
3. scrap car and rent one; use car rental insurance
This will totally depend on how often you need the car, and how much time and effort you are willing to put into it. If it were me, I'd scrap the car, and I'm capable of fixing it... I just wouldn't want to be bothered with it.