Determining the year of JDM Subaru engines

• By basil
• 2 Comments

If you are doing a Subaru conversion (Subaru engine into a VW), you’ll see many Japanese Domestic Market (JDM) engines available.  Many times these engines will be listed as a range.

Here are some EZ30 engines on eBay as an example:

So if you look at the listings above some will have a date range for that model engine.  The last listing shows an EZ30R with date range 2003-2006.  So if you are interested in that particular engine how do you tell what year it is?  From what I’ve found there are no year markings on the case, for example.
Some time ago I ran across an obscure forum entry that said Subaru prints the build month and year on the inside of the oil cap!   

So lo and behold, I checked the inside of our EZ30R’s cap and it shows:

Which we’re interpreting as a motor built in July 2005.   I don’t think many JDM sellers know about this. It’d be trivial to swap caps, for example.  But if you’re picking up an engine off eBay, you may want to ask.