I owned a 600 for a while. Only vehicle I ever had to have towed to a junkyard off the freeway.
I had a 500 owner's manual once, about 40 years ago. In it, weekly maintenance was to open the engine cover and tighten everything you could see.
I knew a guy who had one. Driving down a road, heard a big clunk, gee, everything works, kept going.
Couple of days later, got a little cold, turned the heater on, no heat. Looked under the car, the "clunk" was the heater falling off.