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Old 07-03-2024, 04:48 AM   #36
TheBrightSide
 
Drives: 2010 Chevy Camaro 2SS coupe (MT)
Join Date: Jan 2024
Location: Sacramento, CA - USA
Posts: 371
AFM/DOD specific engine valley cover w/outlet port

Quote:
Originally Posted by morepowerjoe View Post
I'm guessing that you've never seen the bottom of your valley cover correct? The reason I know this is because you should have a pcv system under it.
https://www.carparts.com/details/Che...ll%20-%20Parts
So, idk if I was confused initially or after, but I guess I stick with my original research. What you showed me, is the equivalent of GM P/N 12570471, which is an identical engine valley cover to the one on my LS3 (GM P/N 12599296), except the baffling system underneath the cover, is for AFM/DOD-equipped GM V8 engines.

The LS3 engines don’t have a PCV system like the L99, as far as I’m concerned, which makes use of small orifices in the breather ports (to slow down blow-by). For the Ls3, it simply “recirculates” the outlet (engine valley cover port) to the inlet (intake manifold port), with a “U”-shaped quick-connect valve (GM P/N 12599298), which they identify as a “PCV” (older example, GM P/N 12594779)….

I guess both the LS3 and L99, and other GM V8 engines have part of the PCV system, on the passenger side valve cover. This is where the 90-degree breather port, has a connection routed to the air intake hose. Is the passenger side valve cover port supposed to intake metered air? I remember leaving the valve open or with a breather filter; and both would cause a lean engine condition. Once I either blocked off the passenger side breather port, or connected it to the intake hose, it would resolve the lean CEL code…

Last edited by TheBrightSide; 07-03-2024 at 04:58 AM. Reason: Fixed/revised info
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