Oil Filler Yanmar 3JH2E

[matty47]

Hi, there are two oil fill points on our Yanmar 3JH2E motor. One is on top of the rocker cover (where I would expect one to be) and there is another over the timing gears at the front of the injector pump. There is a breather from the timing gear cover to the air intake and we get some oil collecting in the air intake housing. Can someone tell me if we have to add oil to the gear housing or does the engine oil circulate here. There is no dipstick or level indicator at the gear housing. Neither the owners manual or the service manual make any mention of adding oil to the gear housing.
Thanks for any advice that will straighten this out for us.