The private owner said the HV battery in excellent condition. How do I verify it? By mpg? How about the chance at this mileage of other conventional components failure, such as suspension, bearing...?
At 200K miles you should not be surprised if you have a transaxle or traction battery failure at any time. The fact that the car currently is logging good mpg "today" does not prevent a failure from happening "tomorrow". Some of the failure modes are electrical in nature, and there is no advance warning for such a failure. For example, a common transaxle failure is a high voltage ground fault. There will be no advance notice on that. One day, the wiring insulation within a MG stator deteriorates sufficiently to cause the fault. On the other hand, a transaxle bearing failure is a mechanical fault and this will be made evident by an unusual noise, getting worse over time. There is a high chance that the front struts, rear shocks, and wheel bearings also may need replacement. What to look for is basically the same as any used Prius purchase - and there are many posts about that.
My 2003 has 186,000 miles working normally, yesterday the dashboard lit up with warning lights so I had it towed to the mechanic, today the mechanic said the inverter went and took the tranaxle with it repair cost: 6-8ooo dollars. My car is not worth repairing and if I did the HV battery could break down in a week a=nd that is another 3500.
I did not buy the car, because the body paint looks really pale, and shows a little bit rust as well. I am still kind of optimistic on durability of Prius Gen II, because I don't hear lots of stories of big repairs, at least on this forum, although I know anything could happen at this age, on theory.
I have several customers reaching 300k miles. I see catalytic converter problems and burning of oil. All are on their original suspensions. One customer is close to 400k and I have changed front and rear struts and inner and outer tie rods.
That's good news for me. I always thought, that at almost 200K, the suspension should be replaced, but mine still look OK so far. My 2004 burns oil starting from 150K, at 1qt/2K. Now it is getting worse, probably 1qt/1K. It does not bother me actually, because by adding more oil, it extends the oil change period from 10K to 16K miles. Now I only change oil once a year. I just don't know if it will cause other problems. But so far on this forum I don't hear anything.
I was always told that ADDING oil is not at all the same as CHANGING oil. It may have something to do with contaminants, such as acid, probably don't leave the sump at the same rate the lubricating parts leave. If I were going to fudge on the interval, I'd probably change sooner, when it needs oil added anyway, and skip the filter every other time.
