Saturn S-series with manual tranny and dual overhead cam (SC-2, SL-2, SW-2).
Pick a vehicle you like, with a longer, good sized production run and good aftermarket support. More than 200k built over several years. Buy one or two spares of hard to find, or problem parts, if you can afford them. Do diligent service intervals. Do not put off repairs. Use good quality repair parts. Easier said than done.Forever cars are not cars. They’re trucks.
What fails on the ECU are the capacitors. You replace that you are good for "forever".There's these 2 famous car owners, one a lady that has driven her 1957 Chevy bel air since new. Another that has racked up 3 million miles on his 1966 Volvo. That makes me wonder about my camper van. I want to keep mine forever, but I wonder if it doesn't really work as a forever car. It's a Toyota Previa. A 90s car with an ECU that's been discontinued from Toyota. I won't be able to buy a replacement ECU from Toyota if the ECU dies. I will likely keep the thing until it dies, just to see. But if and when it does, I want to know what would make a good forever car.
I assume it really just needs to be a car which can be worked on easily and will always have market support for parts. Are the best cars for this older American cars? As in early 70s and prior? I wouldn't mind owning an old station wagon and using that as my camper vehicle. I don't need to tow anything. Just space to carry 4-6 people and enough supplies for tent-style camping. I have already been camping 3 times this year and am scheduled for 3 more times this year. I go camping a lot. The Previa of course is doing fine as of now. It's got 200k miles on it now and no rust. Maintained immaculately with top notch fluids.
I have been hesitant to consider it a long term vehicle, because the platform doesn’t lend itself to replacement parts. Toyota is not supporting this oddball much. Most parts are no longer available from Toyota. Engine mounts, brake cylinders, radiators to name a few. I am leery of aftermarket parts supply when it comes to quality. That is why I am considering looking elsewhere.Kurtatron....hold onto that Previa forever. Best van ever made by Toyota. Amazing van. Not sure which seating configuration you have but removing one of the captain's chair (middle row) and the passenger side rear bench seat leaves you w/perfect seating for 4 and w/the one bench seat folded up, ton's of empty space for anything. If you have the supercharged version be sure it check it's fluid level. The one issue w/this engine which I have experienced is oil weeping from valve cover gasket. (Toyota engineer's even accounted for this by the oil drip tray and the oil reserve tank.) Pleasure to drive. Babe Magnet as well....just kidding. Great van for camping. As far as a forever car, I think I would choose a small pickup truck. Something easy to work on and parts are easy to find. Fun to drive and hauling capability. (BTW...The Previa will take a 4x8' sheet of drywall and is capable of taking 10' pieces of lumber and still being able to close the rear hatch!)
2nd gen Lexus GS
Maybe a Mercedes 123 or 126 could be your forever vehicle. Plenty of parts are available, they are a safe vehicle, and with good care, they will last forever. I have had both a 123 (240d) and a 126 (300sd) for 9 years. The 240d was a DD for 8 years until I retired last year. Really good on fuel and was very reliable. The 240d is also very comfortable also. The 300sd is a fantastic road car. I would describe it as majestic. The 1983 240d has the 616 diesel engine which is a forever engine and the 300sd has the 617 diesel engine which is also a forever diesel engine. the 240d weighs 4345 pounds and the 300sd weighs 4750 pounds. They are not lightweight cars!! Good luck in your quest to find a forever vehicle!! I know I have found mine!!I have been hesitant to consider it a long term vehicle, because the platform doesn’t lend itself to replacement parts. Toyota is not supporting this oddball much. Most parts are no longer available from Toyota. Engine mounts, brake cylinders, radiators to name a few. I am leery of aftermarket parts supply when it comes to quality. That is why I am considering looking elsewhere.