New style VS old style PCV?

[Rayyy]

Apparently there is an old style PCV and a new style… Does anyone know which one is which?

I think the one with the small hole is the old style… but, can someone confirm?

 

[afpj]

For MY 2002, it originally came with the larger hole one with spring loaded valve ( rattles when you shake it). The "new" style is the one with the smaller hole, and has no internal spring/valve (no rattle).

 

[Rayyy]

For MY 2002, it originally came with the larger hole one with spring loaded valve ( rattles when you shake it). The "new" style is the one with the smaller hole, and has no internal spring/valve (no rattle).

Wow I thought it was the opposite… Rattler is the new type, no?

My 01 came with a non-rattler pin hole PCV, and the one I ordered was the spring loaded rattler.

Also, some of the videos I’ve seen on YT confirm this

 

[afpj]

Yours must have been replaced at some point. Gm changed to the fixed orifice ( non rattle type) pcv after complaints about oil consumption using the old style “rattle” spring loaded pcv. I am original owner so I’m confident that the rattle type is the older style. There’s a tsb on the fixed non rattle pcv to replace the rattle type. even later, gm switched to a different valve cover without a replaceable pcv.

a tsb is referenced in the following thread: https://www.chevyavalanchefanclub.c...sb-01-06-01-029b-excess-oil-consumption.3606/

 

[OR VietVet]

I have replaced a lot of the rattler old style pcv valves in my shops.

 

[Rayyy]

Is there a way to replace the 03-06 PCV that comes with the valve cover?

I heard a pair of channel locks can be used to twist it out… Is this true?

 

[Mudsport96]

Is there a way to replace the 03-06 PCV that comes with the valve cover?

I heard a pair of channel locks can be used to twist it out… Is this true?

Yes, it requires drilling and a little dremel work to get the right diameter for a grommet to fit. Then get a grommet and pcv for a 02 and prior setup.
Or go to the junkyard and just grab one from a 2002 or earlier vehicle. Ive done it both ways, and use them on my 06 Tahoe and Silverado. Just open up the drain holes in the baffle, they are TINY and plug with carbon. Then the oil goes through the pcv ( either style) and into the intake.
When i worked at the gm dealer we did this often and had zero returns for oil consumption or smoke.

 

[Rayyy]

Yes, it requires drilling and a little dremel work to get the right diameter for a grommet to fit. Then get a grommet and pcv for a 02 and prior setup.
Or go to the junkyard and just grab one from a 2002 or earlier vehicle. Ive done it both ways, and use them on my 06 Tahoe and Silverado. Just open up the drain holes in the baffle, they are TINY and plug with carbon. Then the oil goes through the pcv ( either style) and into the intake.
When i worked at the gm dealer we did this often and had zero returns for oil consumption or smoke.

Nice. Could you clarify which drain holes I would need to open up? Which baffle?

And if I clean these out, is there still a need to replace the PCV valve?

Also, do the 99-02 valve covers fit the 03-06 engines? Could I just install retrofit valve covers if I’m taking off the original ones to do the dremel work?

 

[Mudsport96]

Read this it should help

 

[Rayyy]

Read this it should help

Indeed that thread is very informative.

So, it seems that the older valve covers with enlarged/slotted drain hole is the best of both worlds in the sense that it allows the oil to drain like the updated valve covers (Dorman part# 264-965), yet still has a replaceable PCV valve, ya?

Is there any benefit at all to just install the updated valve cover?

 

[Rayyy]

Ok, here is another very informative thread comparing the differences between the old version and then new version valve covers.

It looks like the new version does have a few additional design changes to help it drain the oil and prevent it from spitting out through the PCV.

https://bobistheoilguy.com/forums/threads/gm-ls-engine-3rd-revision-valve-cover-install.251305/

 

[Rayyy]

Yes, it requires drilling and a little dremel work to get the right diameter for a grommet to fit. Then get a grommet and pcv for a 02 and prior setup.
Or go to the junkyard and just grab one from a 2002 or earlier vehicle. Ive done it both ways, and use them on my 06 Tahoe and Silverado. Just open up the drain holes in the baffle, they are TINY and plug with carbon. Then the oil goes through the pcv ( either style) and into the intake.
When i worked at the gm dealer we did this often and had zero returns for oil consumption or smoke.

So, using the older style (removable PCV valve) valve covers and opening up the drain holes is better than using the updated valve covers with the built-in orifice?? Even if opening up the small drain hole as well?

I also read on another site that drilling out the drain holes can cause oil pressure fluctuations... Does that even make sense?

 

[Mudsport96]

So, using the older style (removable PCV valve) valve covers and opening up the drain holes is better than using the updated valve covers with the built-in orifice?? Even if opening up the small drain hole as well?

I also read on another site that drilling out the drain holes can cause oil pressure fluctuations... Does that even make sense?

Not sure how opening a non-pressurized drain could possibly cause oil pressure fluctuations so i wouldn't worry about that.
As for older pcv with opened drains vs newer orifice with opened drains. I can't elaborate as i have an original pcv valve cover and a newer that i converted to pcv. So both run the old style pcv and have no issues. And in the last year i also added an oil catch can to both vehicles. The Tahoe averages about 2 ounces per oil change and the Silverado about 10 ounces per oil change. But it also has over 400k on the engine so blow by is expected.