LS3 PCV delete with oil mist
Thread Starter
Staging Lane
Joined: Apr 2014
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LS3 PCV delete with oil mist I recorded a video of my 416 ls3 with no pcv. It is blowing out *a lot* of oil mist out of the front of the passenger side valve cover nipple. Is this abnormal? It also likes to drip oil on the passenger side headers after WOT runs can't tell where it is coming from. When I recorded this video, the mist smelled like straight up gas. Then it smelled more oily after the car warmed up.
https://www.youtube.com/watch?v=MasRacFs2mk
https://www.youtube.com/watch?v=MasRacFs2mk
Last edited by bunkerbuster; Apr 30, 2015 at 10:18 AM.
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I couldn't open the link ----are you running a blower?
You really need a PCV. I had the same problem, but after a good RX catch can and a couple of CFM breathers on the valve covers, problem solved. I have two pass side valve covers. The one on the drivers side is an old LS1 truck valve cover with a plastic baffle built in the VC. I heard the LS3 valve covers were a better design, but I have never seen the underside of one. The LS2 vc's only have a metal cover that lets in a lot of oil. I had some oil blowing out of the dipstick also. The working PCV keeps a lot of the fumes out of the engine bay.
You really need a PCV. I had the same problem, but after a good RX catch can and a couple of CFM breathers on the valve covers, problem solved. I have two pass side valve covers. The one on the drivers side is an old LS1 truck valve cover with a plastic baffle built in the VC. I heard the LS3 valve covers were a better design, but I have never seen the underside of one. The LS2 vc's only have a metal cover that lets in a lot of oil. I had some oil blowing out of the dipstick also. The working PCV keeps a lot of the fumes out of the engine bay.
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I don't know why it didn't translate. It should be easy enough to hook up. If he just blocked off the tubes, you can get a GM diagram and make it work.
Thread Starter
Staging Lane
Joined: Apr 2014
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Nothing is blocked except for the nipple on the intake, all hoses disconnected. Oil mist has been getting my engine compartment since. The engine was built for boost. Not sure if that make a difference. Is there a good reliable diagram showing how to plumb an ls3 including a catch can? I just googled, and found 2 conflicting sources.
Last edited by bunkerbuster; Apr 30, 2015 at 10:19 PM.
TECH Fanatic
Joined: Jul 2007
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From: Wilmington, De
The passenger side valve cover nipple is connected to the air intake after the mass airflow sensor. The driver side valve cover nipple is capped.
Then, connect the valley cover nipple to the catch can inlet, and then connect the catch can outlet to the intake manifold nipple.
This is an LS1, but it is the same concept:
The only difference being that the fresh air side is connected at the intake tube instead of at the throttle body.
Then, connect the valley cover nipple to the catch can inlet, and then connect the catch can outlet to the intake manifold nipple.
This is an LS1, but it is the same concept:
The only difference being that the fresh air side is connected at the intake tube instead of at the throttle body.
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Thread Starter
Staging Lane
Joined: Apr 2014
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I guess I'm trying to wrap my head around how it works, but by hooking it into the intake... That works like a vacuum right? Essentially drawing out that oil mist. Or am I way off here? Otherwise, what's the point of piping it back into intake?
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Verdad Gallardo TECH Fanatic
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From: Wilmington, De
The connection at the valve cover draws fresh air into the engine. The connection at the intake manifold acts as a vacuum and pulls the crankcase pressure out. This does draw an oily mist, which is why a lot of people install catch cans on their engines. Some have even gone as far as installing a check valve on the fresh air side to ensure air only travels in one direction.
Thread Starter
Staging Lane
Joined: Apr 2014
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I suppose I have always taken the difference between the L99 and LS3 for granted. Is there a way to distinguish the 2 apart? I bought the TA with the "ls3" already swapped into the TA. Thus, I can't just know by auto vs manual.
Why not just do what the l92s do? Run a pcv valve off the passenger side rear cover to the intake and then a clean air line from the tb to the drivers side valve cover. Or use a catch can to clean the air up but still use the same routing. No need to change valley covers and you'd want a catch can anyway with either setup. Only down side is longer hoses
Thread Starter
Staging Lane
Joined: Apr 2014
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Did any not watch the YouTube video I posted earlier in this thread? For some reason, the oil mist does not blow out anywhere else except on the front passenger side vc. What does that say about the nipple on the driver side vc? If they are truly open nipples from vc to open air, then why not blow out there too?
L92 =\= LS3 when it comes to pcv systems. Based on my reading...
L92 =\= LS3 when it comes to pcv systems. Based on my reading...
I watched the video but its hard to tell? It could just be the way its coming through the engine. Everything in the engine is cross vented so if you plug on orifice off the mist will eventually find its way out of the other side. It could just be at that port most of the oil mist finds the easiest way out.
Yes the l92 system is different but the shortblocks are exactly the same except the l92 has valve reliefs in the pistons. There's no reason an l92 pcv system wont work on an ls3. Since you already have the truck valley cover you could just do what I said above and copy the l99 or l92 pcv system. Or spend the extra 110 bucks and get an ls3 valley cover. That is the more expensive option, either way the engine needs a pcv system.
Yes the l92 system is different but the shortblocks are exactly the same except the l92 has valve reliefs in the pistons. There's no reason an l92 pcv system wont work on an ls3. Since you already have the truck valley cover you could just do what I said above and copy the l99 or l92 pcv system. Or spend the extra 110 bucks and get an ls3 valley cover. That is the more expensive option, either way the engine needs a pcv system.
Thread Starter
Staging Lane
Joined: Apr 2014
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I have plumbed the system, can I get a double checking of this before firing up?:
Intake manifold(vacuum)<=(catch can)=>USA driver side valve cover rear nipple
TB(air)<==>USA passenger side front valve cover nipple
USA passenger side rear valve cover nipple is capped
Valley cover nipple does not exist therefore capped.
I may need to add a check valve/emergency vent off the front passenger side nipple. (Is this literally the pcv valve?? )
Intake manifold(vacuum)<=(catch can)=>USA driver side valve cover rear nipple
TB(air)<==>USA passenger side front valve cover nipple
USA passenger side rear valve cover nipple is capped
Valley cover nipple does not exist therefore capped.
I may need to add a check valve/emergency vent off the front passenger side nipple. (Is this literally the pcv valve?? )