Breather on the Valve Cover and when is it bad?

[GMC Hauler]

After doing the repairs to the injection pump (see Help, my injection pump found loose), i noticed that the breather valve on top of the pasenger valve cover has some oil in it. Can anyone tell me how to test this unit for proper operation? Is some oil in it normal? I am used to seeing another breather on the other side open to atmosphere on gas engines. How does this system work without that other breahter? Thanks.

[gmctd]

That is called the Crankcase Depression Regulator CDR, and is the Diesel version of the PCV system.

Do a "search" (above, opposite the little truck) to get all the CDR information available on this forum, in less than 10 seconds.

Once you've "searched", you'll like it! ;)