Timing belt broke at less than 60K miles, due to a faulty idler pulley, which is the wrong size and application for this car. Idler pulley also contributed to the failure of the next two timing belts I put on it.
Dashboard cracked, and so did the switch POD mounted on it, where the switches are located. Plastic becomes very brittle after several years.
Hard to find parts for the car, such as a water pump, because the car was only manufactured for only 3 years.
Firewall breaks, where the clutch cable is mounted.
Clutch cable broke twice in 15 years.
CV axle boots seem to wear out prematurely.
The car could use about 15 more horsepower.
I used to own a Geo Spectrum, bought it new off the showroom floor in January 21, 1990. It was a 1989 model year car, built in May/89, it was the last year that it was built.
So after 15 years, getting parts for it got harder as the years went by. I broke three timing belts on the car, two times because the idler pulley froze and stretched the timing belt, and the last time, because the water pump leaked over the idler pulley.
I finally quit repairing the car, but you can't really ruin the engine when the timing belt breaks. I had the heads repaired by a machine shop. Had them replace the bent valves, had the heads resurfaced, and it ran like a champ. Cost $155 for machine shop work and labor, $79 for a gasket set from AutoZone, and miscellaneous expenses for reassembling the engine, which I did all the work myself.
The car is practically indestructible, it has its faults, but it got damn good mileage. I finally got rid of it, got $72.10 at a scrap metal yard for it. It got too much; to go out to the salvage yard to look for used parts, especially with my bad back. Wish I had kept it now, but putting on a clutch plate, a new clutch, A/C compressor (which had bad seals), CV axles, and fixing the wiring in the dashboard, became too much for me.
Anyway, I though I would add my $.02 to the discussion.
Ps: Be advised, that the wiring harness under the dashboard will develop problems after several years, due to the fact that the harness is very tight and taut, because of the way it is built at the factory. It will shrink after years, and some wiring will become brittle, and break or short out.
Overall, I would say, that the car paid for itself, the 16 years that I owned it. It served me well.