You are absolutely correct Choda, the valve cover ports are what needs to be on a catch can, that is where the excess oil on LS engines has come from for 15+ years...

 

I see what your saying now Ron. Did you use pipe threaded street elbows to screw into the intake tube?

When he pulled his stock intake tube off there was no oil in there that would have came from the valve covers. So he put the can between the valley and the intake. LS... wtf is that, this is the time of LTX baby!!!!

After seeing the pics and reading this, I am still scared of the oil in there. I think I would still run a catch can on the valve covers. Multiple cans ftw. Maybe even switching up the way the hoses are ran???

Both valve covers - can - check valve - intake.
Valley - can - intake tube.

who knows man, I dont even have one of these trucks yet and driving myself nuts.

 

Per GM:
I haven't crawled around on one yet, but based on GMs description of the routing the only real concern should be the hose going from the valley to the intake. The other two hoses will be flowing fresh air into the valve covers 99% of the time. The only time that won't be the case is during WOT there won't be enough intake vacuum to draw much air in either direction.

This new routing is actually very similar to the way the Corvettes Camaros and GTOs had for years. They always got the more reliable pcv baffle built into the valley where as the trucks drew from the valve covers with little to no baffle.

Anybody noticed the 5.3 and 6.2 foul air tubes are routed differently?

 

Choda, I did use 1/4" street elbows & painted them flat black because that's all I had at the time. I also drilled them out to 3/8" for more flow. The tube had one port tapped & a boss on the bottom that I had to drill & tap. I also used a 1/4" pipe to 1/2" hose fitting & used 1/2" hose instead of 5/8" that the factory uses. The 1/2" will go on the valve cover ports snug & doesn't require clamps. I wanted to clean up the sight of all those hoses so I used the elbows on the tube to route them out of sight as best as I could. I also cut one of the original elbows off that went to the old intake & used it on the left side, the right side I just put the 1/2" hose on it.

I think the LS6 was the first one to have a port in the valley cover & most all performance LS engines since have done the same. I know my L99 Camaro didn't & maybe all DOD engines don't, but the LS3 does. Other LS engines did all vent in one valve cover & out the other, so that's where you used to plumb in the catch can, still on the "dirty" flow side. So...yes, the oil used to come out of the valve covers into the manifold. New LT Series...different & better.

 

You guys are right. Thanks for finding that paragraph and explaining it.

:tup: another reason these new ltx engines are ba

So do u agree that a turbo app would want both valve cover ports going to pre turbo so at wot or any boost it would pull vac from the valve covers?

 

Digging up an old thread, yes. But I'm in the fence for a 2014 Sierra and wonder if oil on the back of the valve is still an issue, is the catch can a cure all and if ya get a second hand truck with like 50k on the clock- how do ya go about cleaning the back of the valves...........

 

Interesting maintenance procedure:

 

Thanks, Bud- feel a lot better about living with DI now..........

 

BG chemicals are pretty top notch. You're gonna need their tool to administer that particular stuff, though.

Richard

 

Huh- nothing off the shelf in a can from like Autozone will do? Saw someone mention bead blasting with a walnut media- but that sounds like ya need to take half the engine apart.........

https://www.walmart.com/ip/Warren-Di...&wl13=&veh=sem