LMM: PCV Valve Question

[CRAWLEN]

been searching to try find the answer to this but no luck.


just to say first i know what a PCV system is for and how it works.



My question is though why does the Duramax have a PCV Valve ? and not like most diesels that don't run a valve as they just use a CCV system that's normally just a filter or mesh on the valve cover. the back in to the intake.


the reason i ask this is because I'm fitting a set of billet valve covers to my built engine that is mainly a daily driver and doing the Crank case vent the same way as the PCV reroutes are normal done. im just a slightly concered about it not having the valve there. and want to know why the duramax has a PCV valve and not just like a filter or mesh like most diesels out there best example is the cummins

 

[CRAWLEN]

Anyone ?

 

[Chevy1925]

Because oil fumes/vapors as well as any fuel vapors are a big big no no from the epa and California. Run it into the intake, the engine instead burns it and it’s then ran through the exhaust cat or back through the egr to be burned again.

 

[CRAWLEN]

yeah i know why its there and what it's for.


What im trying to work out is why has the duramax got a valve though. as its not normal for a diesel to run a valve. as a valve is mainly only for petrol so you don't suffer a vac leak at low revs.


so there shouldn't be a valve on the duramax but there is one. and thats what im trying to work out is why if there is some reason as to why gm put a valve in, instead of just a port out like most diesel. as i don't want to cause any damage to this engine

 

[2004LB7]

Because without a valve and it plummed into the intake it will now be sucking more then when through a filter or mesh. This will cause more oil and vapors to be pulled into the intake then necessary.

 

[Ron Nielson]

From my experience, the PCV system was designed to lessen emissions. Diesels have not been subject to emissions as strict as automobiles and other gasoline engine vehicles. Emissions laws for diesels have grown over the years to even include ships in ports. Everyone wants clean air to breathe, and not dumping engine blow-by into the air is one method of obtaining that.