Updated valve cover (for PCV) details

[iamdub]

Does anyone know what the difference(s) are in the updated valve cover (12570427 for '07 and '08) versus the original one? What about the difference(s) for the '09+ version?

I see there's a hole in a baffle that was relocated, but I recall the PCV hose nipple being longer on the new one. Is there a valve in that port/nipple that was redesigned as well?

 

[buddyhotrod]

1 is old design

2 is new design

 

[iamdub]

Thanks for the comparison pic. Searching images, that's about all I was able to find was that the hole was relocated. It's also square but I don't think that's really very significant. There has to be other differences cuz there are two different designs- one for the older motors and one for the newer. I'm thinking the difference is with the nipple, like maybe how the hose attaches. The updated one for my motor is $100+ whereas the one for the newer motor is about half that. If the only difference is how that hose attaches to the cover, I can just swap my nipple over or cut off the end and use a hose clamp.

 

[donjetman]

WTF, this mystery continues? I posted the following a few days ago and got zero response.

"Valve cover PN 12642655 is cheaper and it fits 09-13 Yukon, Tahoe, Escalade, Avalanche, etc. What's the difference from a 12570427 besides $$$ ?
Here's a link:"
https://www.gmpartsdirect.com/?year...ver&****=&p=catalog&mode=search&search_in=all

 

[iamdub]

WTF, this mystery continues? I posted the following a few days ago and got zero response.

"Valve cover PN 12642655 is cheaper and it fits 09-13 Yukon, Tahoe, Escalade, Avalanche, etc. What's the difference from a 12570427 besides $$$ ?
Here's a link:"
https://www.gmpartsdirect.com/?year...ver&****=&p=catalog&mode=search&search_in=all

Hmmm. I missed that post as well. Apparently, nobody knows for sure.

My most recent findings are that the PCV nipple on the valve cover is the primary difference. The older one's hose is more of a friction fit and I think the newer one uses a locking O-ring fitting. The nipple diameters are different as well. If those nipples are just hollow ports for the hose to attach to and have nothing inside them (such as a check valve like a traditional PCV valve), then I don't see why the only real concern would be a matter of getting your hose to fit onto the nipple.

I'm leaning towards borrowing an updated valve cover from the parts store for measuring and studying. Then just cutting a square hole in the baffle of my stock valve cover with a rotary tool and using the removed piece to weld up the original hole, essentially copying the updated design.

If that differently-sized nipple is specifically engineered to meter the flow as part of the PCV improvement changes, then I'd just get the newer/cheaper one. Really- how hard would it be to make a hose with very little pressure in it fit a nipple that's either a little smaller or larger? Shim down the hose's ID if the nipple's smaller or splice a larger hose to the stock hose to increase the ID to fit a larger nipple.

 

[swathdiver]

I'm thinking the difference is with the nipple

You're right. It's the diameter of hose used that's different so the fitting is different. I don't remember what the sizes were but there were side by side photos on a google search.

 

[omandave]

I redid the top end of my 09 burb a couple of years ago. the updated cover moves the PCV "vent hole" away from the corner, in an effort to reduce the amouint of oil that gets sucked up into it when parked on a hill. The redesign is alleged to have helped, as part of trying to solve the "oil burner" effect. I replaced the AFM valley plate with a newer 2011+ design as they removed several screens that would get clogged and oil starve the AFM cylinders...
I have had a much smoother, less oil thirsty ride since then. (Before, 1 qt every 800 miles. now 1 quart every 3000 miles.)

YMMV.
Cheers!

 

[iamdub]

You're right. It's the diameter of hose used that's different so the fitting is different. I don't remember what the sizes were but there were side by side photos on a google search.

Would you say this size difference is part of the oil consumption improvement measures?

I'm just trying to decide if I should get the updated valve cover for the newest engine design and adapt it to my '08 or if the updated design that's made for mine will be just as effective. If so, I'll just modify my existing one to mimic the updated one and save the $100+.

 

[iamdub]

I redid the top end of my 09 burb a couple of years ago. the updated cover moves the PCV "vent hole" away from the corner, in an effort to reduce the amouint of oil that gets sucked up into it when parked on a hill. The redesign is alleged to have helped, as part of trying to solve the "oil burner" effect. I replaced the AFM valley plate with a newer 2011+ design as they removed several screens that would get clogged and oil starve the AFM cylinders...
I have had a much smoother, less oil thirsty ride since then. (Before, 1 qt every 800 miles. now 1 quart every 3000 miles.)

YMMV.
Cheers!

When replacing my motor mounts recently, I noticed that my VLOM had a date stamp of 2014. I deleted the pic so I don't have the part number at the moment. Any chance you have the part number for this updated VLOM (valley cover)?

 

[swathdiver]

Would you say this size difference is part of the oil consumption improvement measures?

I'm just trying to decide if I should get the updated valve cover for the newest engine design and adapt it to my '08 or if the updated design that's made for mine will be just as effective. If so, I'll just modify my existing one to mimic the updated one and save the $100+.

I reckon it would be fine to get the one made for yours and leave it plug and play; no messing with changing hose sizes. Or modify your original since that's an easy task for you!

When replacing my motor mounts recently, I noticed that my VLOM had a date stamp of 2014. I deleted the pic so I don't have the part number at the moment. Any chance you have the part number for this updated VLOM (valley cover)?

PN# 12571609 is the one that was installed by GM on my truck in December 2016.