Its hard to add up the entire cost of the car. There's the cost of time spent; time without a car; lost opportunity due to car issues. And in the end, you're driving an old, worn car which isn't as 'valuable' as driving a new, unworn one.
Depending on how all this is weighted and added up, it can be the right thing to replace a car sooner than later.
Depending on how all this is weighted and added up, it can be the right thing to replace a car sooner than later.