How to tell you are not getting another 2010 used motor

In the US market anyway, the engine will have a VIN plate securely riveted to it (thank you for not buying one where the plate has been removed or scratched out), and you can use the year position of the VIN to find out how old it is (or even look up carfax, etc., history for that VIN).

I don't know what identifying number would be on a JDM engine though.

 

I think all Prius are made in Japan, so maybe all the same codes?

 

All Prius engines are made in Japan, but they are only required to stamp USA-legal VIN numbers on the cars destined to be sold in America. I'm not sure they're required to put them on the engines, to be honest.

There will be other numbers on the engine casting which Toyota can use to figure out when and where the engine was produced. However, Toyota is under no obligation to tell the public how to decipher those codes because that is their internal numbering system and not a federally regulated statement.

The real answer:

Buy from a known and respected autoparts recycler. Most of what they sell isn't dated or marked, but they have to sell good parts today to have a job tomorrow, and most of them take this very seriously.

 

Here's the riveted-on plate where you'll find the VIN (if the engine was built for the US market).



As always, thank you for not buying an engine with the plate removed or scratched out.

 

For orientation, I think you're around back of the engine, near the passenger end (aka front) of the engine, looking forward horizontally, and the flagged component is the (beltless) pulley on the end of the driveshaft.