They are similar to the Y22 Nissan engine. And internal injectors on any engine is a good reason the dipstick should be checked regularly. The injector seals can fail and diesel gets into the sump, and the (diluted) oil level in the sump rises. Failure to check can lead to serious engine damage, more often than not by self detonation. just for clarity those particular seals bridge the gap between rocker cover and injector.
regards
Dave