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I have done alot of searching and can't really find a solid answer. I have been having a oil consumption problem about a quart every few days. Oil all in intake and duct work as well as all 8 plugs covered in oil. Originally thought it was a crank case breather problem with my H/C put a oil separator on and it helped a little. Does anyone know if the ls6 valley cover built in pcv system can fail. As in letting way too much oil through or if maybe there waa a recall on them and possibly a replacement part. Does H/C possibly increase crank case pressure too much allowing it to push oil through and I have to run a pcv valve as well to increase the systems efficiency?
I also see that the internal pcv system has what looks like nuts on it in the pictures, does anyone know if that part it self is serviceable and has a part number for it.
Last edited by Vetteman Jack; Mar 20, 2024 at 02:01 AM.
. "Does H/C possibly increase crank case pressure too much allowing it to push oil through and I have to run a pcv valve as well to increase the systems efficiency?
Am I to understand you are not running a PCV valve? No expert but that could be the problem.
the ls6 valley cover doesn't require a pcv valve in its stock form the pcv system is a built in air/oil seperator
That is not correct. It does need a PCV valve, the factory part number is 19313320. A PCV valve is not an oil air separator. I will not be the only one who tells you this as well.For reference, I have a 2003 Z06, with an Elite Engineering catch can and an otherwise stock LS6 engine. I don't race it, nor am I in the habit of routinely beating on it, but I do put my foot in it occasionally. I generally see about 1/8 of a canister's worth of oil collect in the catch can in 10k miles.
Posted by another member:
"First of all, it sounds like you had some invasive engine work performed. Was everything reassembled properly? The same goes for the catch can; you wouldn't be the first, nor the last to make a mistake. It's easy to do.
Piston Rings: Worn piston rings will allow oil past the rings and into the combustion chamber, where it is burned. Failed piston rings can cause blowby (where combustion gasses blow past the rings and into the crankcase) which can easily overwhelm the PCV system and pressurize the crankcase. If you remove the oil filler cap, this will typically look like an old time steam locomotive puffing away out of the valve cover. I haven't seen one in decades, but you used to be able to get a tool that measures the amount of air escaping through the filler neck, in order to determine if it is excessive. If it is excessive, however, there likely won't be any doubt in your mind, as you can typically also hear the puffing sound accompanying the smoke escaping from the filler neck. Note that the engine may not idle with the filler cap removed, as this causes a substantial vacuum leak, so you may need to give it a wee bit of throttle to get it to idle. Note also that you may see oil leaks due to the pressurization of the crankcase.
Valve Stem Seals: Failed valve stem seals will allow oil past the valve guide and into the combustion chamber, where it is burned. Worn valve guides may prevent the valves from sealing properly and may also allow the valve stem to rock back and forth, more than the valve stem seal can cope with. If you have a camshaft with extremely high lift, the valve guides can be subjected to excessive wear in a very short time span.
PCV System: When the PCV system fails, it is common for oil to begin seeping from every possible seal and gasket on the engine. Safely, get the car up in the air and have a good look underneath. The lack of functioning crankcase ventilation system can also turn your oil into sludge in only a couple thousand miles! There are many reasons why the PCV system may fail. On a +/- 20 year old car, I would start with the hoses. Rust may be forever, but not rubber. Due to age, heat cycles and exposure to oil vapor, rubber hoses may get hard and crack, or they may get soft and suck shut closed under intake manifold vacuum. Either situation is obviously a serious problem.
Some PCV valves have a metered orifice and a check ball with metered passages, Other PCV valves only have a metered orifice. It should go without saying that if yours has a check ball, that ball should rattle when you shake the valve. Either type of valve can get clogged with crud, effectively disabling the PCV system. As already mentioned, LS1 & LS6 engines have a liquid vapor separator located in a somewhat unconventional spot ... the valley of the engine. These liquid vapor separators have a poor reputation for allowing excessive oil into the intake manifold, via the PCV system, where the oil is eventually burned in the combustion chamber. And, that's if these liquid vapor separators are working properly. If they have failed, then the flood gates could potentially open, pouring generous amounts of oil into the intake.
The "When in doubt, renew throughout" strategy is both costly and time consuming. Unless you see an obvious cause to your problem, always start by checking the basic mechanical condition of the engine. This includes both a dry and wet compression test and a leak down test. If you have low compression, then you have a mechanical problem that needs to be addressed before proceeding. If the compression jumps up after adding a squirt of oil into the cylinder, then this suggests a ring problem. A leakdown test gauge helps to quantify the amount of leakage, but just as importantly, where is the pressure leaking to? Is it leaking into the intake manifold (via the intake valve), is it leaking into the exhaust system (past the exhaust valve), or is it leaking into the crankcase (via the rings)? Listening at the throttle body (preferably with the throttle blade open), at the tailpipe(s), or at the filler neck helps to narrow the cause ... valves not seating properly, or an issue with the rings.
All of the aforementioned tests and observations provide individual clues as to what is going on inside of your engine. It is your job to play detective and assemble these clues into a coherent picture. Granted, this may be somewhat challenging if you have multiple problems, or if two different problems have similar symptoms. But, be patient, go about things methodically, update us periodically and ask questions. There is no such thing as a stupid question, when you are learning."
That is not correct. It does need a PCV valve, the factory part number is 19313320. A PCV valve is not an oil air separator. I will not be the only one who tells you this as well.For reference, I have a 2003 Z06, with an Elite Engineering catch can and an otherwise stock LS6 engine. I don't race it, nor am I in the habit of routinely beating on it, but I do put my foot in it occasionally. I generally see about 1/8 of a canister's worth of oil collect in the catch can in 10k miles.
Posted by another member:
"First of all, it sounds like you had some invasive engine work performed. Was everything reassembled properly? The same goes for the catch can; you wouldn't be the first, nor the last to make a mistake. It's easy to do.
Piston Rings: Worn piston rings will allow oil past the rings and into the combustion chamber, where it is burned. Failed piston rings can cause blowby (where combustion gasses blow past the rings and into the crankcase) which can easily overwhelm the PCV system and pressurize the crankcase. If you remove the oil filler cap, this will typically look like an old time steam locomotive puffing away out of the valve cover. I haven't seen one in decades, but you used to be able to get a tool that measures the amount of air escaping through the filler neck, in order to determine if it is excessive. If it is excessive, however, there likely won't be any doubt in your mind, as you can typically also hear the puffing sound accompanying the smoke escaping from the filler neck. Note that the engine may not idle with the filler cap removed, as this causes a substantial vacuum leak, so you may need to give it a wee bit of throttle to get it to idle. Note also that you may see oil leaks due to the pressurization of the crankcase.
Valve Stem Seals: Failed valve stem seals will allow oil past the valve guide and into the combustion chamber, where it is burned. Worn valve guides may prevent the valves from sealing properly and may also allow the valve stem to rock back and forth, more than the valve stem seal can cope with. If you have a camshaft with extremely high lift, the valve guides can be subjected to excessive wear in a very short time span.
PCV System: When the PCV system fails, it is common for oil to begin seeping from every possible seal and gasket on the engine. Safely, get the car up in the air and have a good look underneath. The lack of functioning crankcase ventilation system can also turn your oil into sludge in only a couple thousand miles! There are many reasons why the PCV system may fail. On a +/- 20 year old car, I would start with the hoses. Rust may be forever, but not rubber. Due to age, heat cycles and exposure to oil vapor, rubber hoses may get hard and crack, or they may get soft and suck shut closed under intake manifold vacuum. Either situation is obviously a serious problem.
Some PCV valves have a metered orifice and a check ball with metered passages, Other PCV valves only have a metered orifice. It should go without saying that if yours has a check ball, that ball should rattle when you shake the valve. Either type of valve can get clogged with crud, effectively disabling the PCV system. As already mentioned, LS1 & LS6 engines have a liquid vapor separator located in a somewhat unconventional spot ... the valley of the engine. These liquid vapor separators have a poor reputation for allowing excessive oil into the intake manifold, via the PCV system, where the oil is eventually burned in the combustion chamber. And, that's if these liquid vapor separators are working properly. If they have failed, then the flood gates could potentially open, pouring generous amounts of oil into the intake.
The "When in doubt, renew throughout" strategy is both costly and time consuming. Unless you see an obvious cause to your problem, always start by checking the basic mechanical condition of the engine. This includes both a dry and wet compression test and a leak down test. If you have low compression, then you have a mechanical problem that needs to be addressed before proceeding. If the compression jumps up after adding a squirt of oil into the cylinder, then this suggests a ring problem. A leakdown test gauge helps to quantify the amount of leakage, but just as importantly, where is the pressure leaking to? Is it leaking into the intake manifold (via the intake valve), is it leaking into the exhaust system (past the exhaust valve), or is it leaking into the crankcase (via the rings)? Listening at the throttle body (preferably with the throttle blade open), at the tailpipe(s), or at the filler neck helps to narrow the cause ... valves not seating properly, or an issue with the rings.
All of the aforementioned tests and observations provide individual clues as to what is going on inside of your engine. It is your job to play detective and assemble these clues into a coherent picture. Granted, this may be somewhat challenging if you have multiple problems, or if two different problems have similar symptoms. But, be patient, go about things methodically, update us periodically and ask questions. There is no such thing as a stupid question, when you are learning."
where is the pcv valve located, All I have is the little valley cover nipple and the rubber hose. Is it built in underneath? Ive been told my multiple people that there isn't actually a pcv valve like the older ls1 style pcv system? Guessing that is wrong
It is on a hose just after the nipple of the valley cover. If you go the the C5 General subforum and check out the thread "a few hours in the shop and she is a new machine" and check out the 8th pic down you can see it mounted to the valley cover. In the first pic you can see the stock location where the hose comes off the valley cover, curves around with the PCV valve plugged into the throttle body.
It is on a hose just after the nipple of the valley cover. If you go the the C5 General subforum and check out the thread "a few hours in the shop and she is a new machine" and check out the 8th pic down you can see it mounted to the valley cover. In the first pic you can see the stock location where the hose comes off the valley cover, curves around with the PCV valve plugged into the throttle body.
thank you, Thats the problem i bought this car with how the pcv is currently set up and im assuming they for some reason took out the pcv valve cause all i have is a skinny hose that a pcv cant fit in.
thank you, Thats the problem i bought this car with how the pcv is currently set up and im assuming they for some reason took out the pcv valve cause all i have is a skinny hose that a pcv cant fit in.
The 04 corvettes did not have a PCV valve. My 04 does not have a valve there. The airflow is regulated in the valley pan by an orifice. The earlier corvettes did have a PCV in that location. If you put one in, it will be interesting to see what it does. An easy thing to do.is pull off the oil fill cap and cover it with your fingers. You should feel a small vacuum and you should not feel strong puffs of air. If you do thats a blowby problem.
Last edited by C5MSG2004Vert; Mar 20, 2024 at 01:15 PM.
The 04 corvettes did not have a PCV valve. My 04 does not have a valve there. The airflow is regulated in the valley pan by an orifice. The earlier corvettes did have a PCV in that location. If you put one in, it will be interesting to see what it does. An easy thing to do.is pull off the oil fill cap and cover it with your fingers. You should feel a small vacuum and you should not feel strong puffs of air. If you do thats a blowby problem.
well do you happen to know if that system can fail because it's putting alot of oil into my intake. As well as what to do about it?
well do you happen to know if that system can fail because it's putting alot of oil into my intake. As well as what to do about it?
I saw a post that said there is an oil seal in the valley pan and it's replaceable but thats all I have read. Not sure if its true. You should check if you have excessive pressure at the oil filler tube. You can do this by removing the cap and just placing your fingers over the opening with the enginerunning. Lots of pressure and smoke is a problem.
Honestly it can go where ever between the valley cover nipple and the intake manifold nipple or catch can. I can get a pic tomorrow of where I put mine, it is right after the nipple on the cover tucked in behind the belt tensioner. I then continue the hose to my catch can. I just used regular hose instead of the GM part, 5/16 ID IIRC. Here is where I have my PCV located.
Honestly it can go where ever between the valley cover nipple and the intake manifold nipple or catch can. I can get a pic tomorrow of where I put mine, it is right after the nipple on the cover tucked in behind the belt tensioner. I then continue the hose to my catch can. I just used regular hose instead of the GM part, 5/16 ID IIRC. Here is where I have my PCV located.
thank you I basically have it set up like that with my own hose desgin without a catch can and it has slowed down the oil issue but has eliminated it to a acceptable standard, going to go after the pcv system under the valley cover next to see if thats the issue. Thank you all for the help
Ls6 valley cover pcv problem
