Framing the old cost of repairs in this way makes it a gut wrenching mess to stand at the parts counter and buy ANYTHING for these old beasts. I think it is much better to consider the true cost of the alternatives, ie buying a replacement car, new used, bicycle, walk, stay home, keep the wreck as is and complain...
The real question should be what can I do with the problem to solve it today. What is possible and will it make any sense.