Years ago I bought a 1979 Chrysler Newport for $250 from the junkyard, which still ran pretty well. I thought it only had 130,000 miles on it. But when I saw the title of the previous owner, I saw that he had bought it in 1985 with 105,000 miles on it. This was late 1996. So either that car was driven another 25000 miles over the course of 11-12 years, or it was more like 230,000.
That sucker ended up costing around $900 to put through inspection. It needed new tires (I got junkyard tires cheap), new front brake pads and rotors (those big old heavy 1-piece expensive rotors). It also needed 4 big bushings that separated the subframe from the body (Chrysler was a pioneer of unitized construction, but that has both good and bad connotations) and some other things.
Well, soon after I got it on the road, the tranny quit on me. That was another $650. The parking brake went bad. I think that was around $100. The steering column actually BROKE! That was around $350. The starter went bad on it too. Power steering pump went bad.
Then my Mom gave me an '86 Monte Carlo with around 179,000 mostly highway miles on it, and I didn't drive the Newport that much. Until the Monte got T-boned. Then I was back to the Newport. One night the water pump went bad, and I said that was it. I'm not putting another dime into it, and I'm getting something else! Looking back, I wish I'd just paid the $300 or so for the water pump.
I ended up selling it for parts, and got around $300 for it. In total though, I'd say I sunk around $2400 into that car (once I back out the sale price). I had owned it for about 2 years (bought it in late 1996, sold it in late 1998) but had only really driven it for about a year. Didn't put it on the road until April 1997, go the Monte in March 1998, and then didn't drive the Newport much after that until the water pump went out a few months later. Then the thing sat around most of the summer and fall until I finally sold it.
I thought it was really sinking me financially, but I still managed to get 18,000 miles and a year of service out of the car for $2,400, or about $200 per month. Not really bad, I guess for a high-mileage domestic picked up from the junkyard! So it seems to me that a car would have to become VERY unreliable and before it became cheaper to buy a newer one. I'd guess eventually you'd just get to the point that the body integrity was so bad that it became unsafe to drive, or something got rusted out so bad where part of the suspension connected, that it just wouldn't be worth it to fix.
If I had just gotten that water pump fixed, I probably could've gotten many more years out of that car. But I just wanted something that was newer, lower mileage, with more options, a working a/c, and a nicer stereo.
