Is it safe to buy a 2012 with rebuilt engine from someone who said they retired as a Toyota tech?

3rd Gens are not bad. Some people think so. They have problems just like all the other cars.
They are just different.
Mine is great! Original hybrid, brake master cylinder and acumilator and inverter.
Replaced the head gasket at 301,6xx miles.
All I've replaced is the normal wear and tear items.
Brake pads, front and rear. Wheel bearings, front and rear.
Replaced the rear deck lid shocks 2 weeks ago.
It does need struts and shocks.
The engine uses 1-2 quarts in 5000 miles, depending on how I drive it.

I've talked to about a dozen other Gen 3 owners and they haven't had any problems either.
I believe it depends on the car and who'd driving it, and how they drive it and take care of it.

Prius Chat is full of people who have a problem and are looking for inexpensive fixes.
Very few people on here that don't have probems, they don't need to be.
They spend their time doing other things.

 

Sure, there are lots of good gen 3’s.
But how can we tell you which ones?

 

My money's on:

1. 5k miles or 6 month oil changes.
2. Thorough EGR and intake manifold cleaning every 50K miles.

I'm at 98K kms, original pistons/rings, EGR components, intake manifold. No problems, zero oil consumption.

But the people selling theirs, they tend to be: "religiously" dealership serviced, EGR never touched, underpanels dragging (or cut off), head gasket letting go.