Oil consumption, and possible PCV valve addition??? - Page 2
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 16 to 28 of 28
Like Tree2Likes
Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, Oil consumption, and possible PCV valve addition??? in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; The PCV valve isn't designed to prevent oil flow. It's designed to increase crankcase ventilation which is why PCV stands ...
  1. #16
    Doug In NC is offline Cadillac Owners Member
    Automobile(s): Friend of CTS Owner
    Join Date
    Sep 2010
    Age
    36
    Posts
    60

    Re: Oil consumption, and possible PCV valve addition???

    The PCV valve isn't designed to prevent oil flow. It's designed to increase crankcase ventilation which is why PCV stands for Positive Crankcase Ventilation. Things like baffles in a valve cover and oil separators are designed to reduce the ingestion of oil itself. The ball or Check-valve in the PCV valve that we're all used to seeing is there in the event of a back-fire as well as to restrict/meter flow of this ventilation system. If the ENGINE didn't have a PCV system then these fumes that build up during the combustion process would never be forcefully pulled out and would break down engine oil quicker as well as increase the chances of oil caking up.

    In the event of a back-fire, the check valve is shut to prevent the flame from leaving the intake manifold and entering the crank-case which has fumes from the oil heating up and slight blow-by (in a good running engine) which could ignite if this flame made it in. This valve also helps prevent boost from entering the engine in cases where the vehicle has forced induction.

    There are other ways of creating a positive crank case ventilation system without having a check-valve designed system. On Jeep 4.0L's for instance that have the large and open fresh air inlet "Orfice" which allows air from the air filter box to enter the valve cover. A second "Orfice" allows the engine vacuum to pull the fumes out. Unlike the first orfice though, the second one on the vacuum side has a much smaller opening which prevents excessive flow. Couple this with baffles in the top of the valve cover and you now reduce the amount of oil that gets sucked up while still accomplishing the PCV process.

    My friend's got an 05 CTS which has the timing chain noise and goes through over 2 quarts of oil between 3K oil changes using synthetic. I plan on doing the timing chain job this winter as well as replacing the plugs and bringing the rest of the car up to maintenance standards for the mileage. I hope to be able to find out more about the oil consumption and timing chain issues then but I'm willing to bet that if there is no serviceable PCV valve then the straw-like hoses mentioned already are designed in a similar fashion to the jeep orfice design.

    Doug
    manoogia and manoogia like this.

  2. #17
    briggy's Avatar
    briggy is offline Cadillac Owners Enthusiast
    Automobile(s): CTS 3.6L 2005 80,000 Miles
    Join Date
    Dec 2009
    Location
    Southern California
    Age
    39
    Posts
    719

    Re: Oil consumption, and possible PCV valve addition???

    Quote Originally Posted by Bluehaze07 View Post
    Hey,

    I have the same engine and the oild consumption is starting to happen more often then 1qt per 1000 miles. I did some searching and found a TSB that may help answer the question. A tech stated that replacing piston rings and valve guide seals may fix the issue. Is there a Install DIY/MOD for the PCV in the engine to help?

    TSB Bulletin No.: 01-06-01-011E

    Having done a rebuild on my 05 3.6L the guy who rebuilt the heads said the guides were prematurely worn (90,000 miles). Unfortunately I wasn't able to address the rings aside for a 24 hour soak in GM upper engine cleaner (incredible stuff by the way). I've also been told and can verify the front engine cover is also a prime candidate for oil loss.

  3. #18
    Joe
    Joe is offline Cadillac Owners Fanatic
    Automobile(s): 08 CTS blk/blk
    Join Date
    Jul 2010
    Location
    MA
    Age
    66
    Posts
    290

    Re: Oil consumption, and possible PCV valve addition???

    Doug thank you for that awesome info.

    briggy, quick question, are the valve guides aluminium on these engines?? If they are that would explain why they're wearing down so fast and allowing oil to pass. The valves need SOME oil but this is way too excessive. Do you recall what the valve seals look like also? I hope the're not still using those O'rings

    Love this forum,

    Joe

  4. #19
    briggy's Avatar
    briggy is offline Cadillac Owners Enthusiast
    Automobile(s): CTS 3.6L 2005 80,000 Miles
    Join Date
    Dec 2009
    Location
    Southern California
    Age
    39
    Posts
    719

    Re: Oil consumption, and possible PCV valve addition???

    Quote Originally Posted by Joe View Post
    Doug thank you for that awesome info.

    briggy, quick question, are the valve guides aluminium on these engines?? If they are that would explain why they're wearing down so fast and allowing oil to pass. The valves need SOME oil but this is way too excessive. Do you recall what the valve seals look like also? I hope the're not still using those O'rings

    Love this forum,

    Joe

    sorry don't have that info, just dropped em off at the machine shop. I do know they guy had a hard time finding the guides. I guess the dealer standard response is replace the heads. He ended up having to take dimensions on the guides and do a comparison check. How much oil is in fact coming through the guides/seals I don't know. I just say don't rule out stuff like the front cover.

  5. #20
    Doug In NC is offline Cadillac Owners Member
    Automobile(s): Friend of CTS Owner
    Join Date
    Sep 2010
    Age
    36
    Posts
    60

    Re: Oil consumption, and possible PCV valve addition???

    I just started the timing chain job on my friend's 05 and wanted to follow up with some more info regarding the PCV system.



    The first picture above shows where the fresh air for the PCV system comes from. There's a fitting on the air boot after the MAF that allows filtered air to enter the driver's side valve cover.



    This second picture shows the other end of that hose connecting to the valve cover, it's just rearward of the last coil on that bank. If you note the convoluted tubing with the white label, that's the hose and it goes to a 45 degree fitting coming out of the valve cover that is under the brake booster vacuum hose shown in this picture above.



    If you'll look at the intake plenum, there's a black hose that enters both sides of if, just below the shiny freeze plug looking component.




    Spray the fitting down with some sort of lubrication and take a flat blade screw driver and twist it out. Be careful and use plenty of lube because the o-rings on this orfice tube can tear on the not-so-smooth aluminum plenum. As you can see in this picture, there's a little bit of orange still in the opening. That's where the o-ring tore a little bit.




    On it's way out you'll notice that there's some resistance because of the length that it extends inward as well as the rear sections of the hoses being bolted down. See below pic for the rear section being unbolted from the backside of the intake plenum, just rearward of the brake booster hose which has the blue paint on it:






    With the orfice removed completely from the intake you can look down in there with a flashlight and see that there's really not a lot of restriction in there (hopefully)




    Above you'll see the where this other end of this vacuum related PCV hose seats on to a fitting from the passenger's side valve cover, just above the yellow fuel line label.




    This picture shows the complete VACUUM side of the PCV system, upper left where it goes in to the passenger side valve cover and the there's a "T" on the backside of the intake and the hoses continue up to the middle/side of each bank.

    The part that attaches to the passenger side valve cover has a spring loaded clip (it's just plastic that is bent to provide the spring action) that has to be carefully released to prevent it from braking, see pic below:



    They split the vacuum hose portion so that, in theory, one bank alone is not saturated with all of the crank-case fumes/vapor/oil. Also, there is no function PCV valve like we're used to seeing, no check valve, spring and ball or whatever. It appears to be a restrictive hose where the diameter itself meters the airflow. With the vacuum side PCV hose off you can suck or blow in to any end of it the flow is the same and does not become blocked like a check valve would.

    The underside of the intake plenum shows that oil is definitely making it's way in to the intake stream causing the oil consumption that we've been chasing since he bought the car used a year or so ago. The mileage on this model is just over 75,000.





    Additionally, below you'll see two pictures of the spark plug. The first picture shows the white crusty build up that you could expect to see in an engine that has excessive oil making it's way to the combustion chamber.





    This second picture shows the same plug rotated 180 degrees. Based on the lack of deposits on this side it would be easy to believe that the first side is the side facing the intake port itself where the oil would contact first and the second is cleaner because of the lack of exposure.










    The last two pictures show the intake manifold itself, still attached to the engine. It's pretty clear that one bank has been exposed to more oil than the other but I really don't have an explanation as to why nor do I have a decent plan for reducing the problem. You can also note where the two hoses come together as one and then lead over to the valve cover. Also, it's important to note that if you plan on doing something with the PCV system you'll need to remember that you're dealing with a Mass Airflow Engine Management system. This means that any attempt to vent the PCV system, add in a catch can with a filter or stick one of those cool little air filters that fit on your pinky on the valve cover then you may create a fuel trim issue leading to a Rich/Lean condition. In other words, if you add in a catch can, it has to be sealed and only pulling air from the properly sealed up valve cover and getting it's fresh air from the post-maf filtered air.

    Additionally, the PCV hoses shown above can become brittle on high mileage cars. The convoluted sections will become brittle and won't like to bend out of the way. Additionally, the softer rubber boot that goes to the driver's side valve cover will become softer and may not be a tight seal on high mileage cars as well. This again can cause a MAF trim issue and the solution will be to either replace the hose with a new one or put a hose clamp on it. From my experience, the hose clamp can work good for a while but if the boot is ultra soggy to begin with, the clamp will cut the hose and cause it to fail as well. Finally, if you don't use an OEM replacement hose and try to piece it together with hose from the parts store then you should know that not all hoses are equal. I've work on quite a number of cars where people put heater hose on where PCV hose was used before. This looks and fits fine for a while but give it a year or so and the hose that works for coolant will swell up the longer it's exposed to oil and crankcase vapors.
    Doug

  6. #21
    Doug In NC is offline Cadillac Owners Member
    Automobile(s): Friend of CTS Owner
    Join Date
    Sep 2010
    Age
    36
    Posts
    60

    Re: Oil consumption, and possible PCV valve addition???



    Some additional pictures now that the valve cover is off you can see the orfice in the back of the passenger side valve cover. It's just a small opening so the metering takes place here.



    On the underside you can see that there are no baffles but the design of the cover will prevent oil from the lifters/cams/etc from sloshing directly up in to the orfice. Also, the openings on the underside of the orfice are quite small.



    In addition to the separated passage you can see the back side of the cylinder head is cast in such a way that it will pull fumes from the head but it's certainly not a direct shot.

  7. #22
    454Casull is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS 2.8L 6MT
    Join Date
    Apr 2010
    Posts
    386

    Re: Oil consumption, and possible PCV valve addition???

    Nice breakdown-in-progress. Hope you find what you're looking for.

  8. #23
    airportwv is offline Cadillac Owners Member
    Automobile(s): CTS 2006 2002 SLS AN BMW R1100RT
    Join Date
    Dec 2008
    Location
    CHARLESTON WV
    Posts
    75

    Re: Oil consumption, and possible PCV valve addition???

    i have a 2006 3.6 1 qt =1000 miles an no oil leak

  9. #24
    REDLT4 is offline Cadillac Owners Member
    Automobile(s): 2005 CTS
    Join Date
    Jan 2011
    Posts
    28

    Re: Oil consumption, and possible PCV valve addition???

    I was curious if you found a solution to this issue? I have oil in the air box from the line coming from the driver side valve cover. I'm wondering if this is my oil consumption prob, and Could I fix it with some sort of catch can.

  10. #25
    odthetruth's Avatar
    odthetruth is offline Moderator
    Automobile(s): 2006 CTS-V
    Join Date
    Feb 2010
    Location
    NYC
    Posts
    4,983

    Re: Oil consumption, and possible PCV valve addition???

    I'm positive you can set up a catch can in the meantime while you trace down the actual cause and a more long term fix for this. Good luck to you guys. I'm a 3.2 guy, so I can't be of much help.

  11. #26
    trax is offline Cadillac Owners Member
    Automobile(s): '04 1SC CTS
    Join Date
    Jan 2007
    Location
    Western Chicago Suburbs
    Age
    31
    Posts
    47

    Re: Oil consumption, and possible PCV valve addition???

    Bump!

    I had my upper intake off of my 3.6L last night to replace my spark plugs, and I noticed the exact same issue. I have tons of residue in the intake runners (both banks). My intake elbow is also so wet with oil that when I tilt it from side to side you could watch the residue run and pool.

    Any ideas?

  12. #27
    Kilowatt is offline Cadillac Owners Member
    Automobile(s): CTS
    Join Date
    Jun 2013
    Location
    Kansas
    Age
    49
    Posts
    12

    Re: Oil consumption, and possible PCV valve addition???

    Anybody posted what oil losses as like, a record quantity? I just got done driving 750 miles at fairly high average mph (70-80mph) on mostly flat kansas roads and my '05 3.6 sucked down 3 quarts of fresh mobil 1. I am not happy to discover that.
    Okay so I've got an oil guzzler but you would think that oil consumption of this magnitude would produce a cloud of blue smoke out her back end...I never see anything and the back end of the car does not have any traces of oil droplets, fumes or smoke residues...so how does this work?

  13. #28
    DavidBoren's Avatar
    DavidBoren is offline Cadillac Owners Enthusiast
    Automobile(s): Volant, VMAX, RX catch can, tranny cooler... RIP
    Join Date
    Jul 2012
    Location
    Portland, OR
    Age
    29
    Posts
    524

    Re: Oil consumption, and possible PCV valve addition???

    Kilowatt,
    3qts in 750 miles? That is an absurd amount of oil loss. Are you sure, SURE, that it was full when you left? Do you have a leak anywhere? Even at WOT, that amount of oil being sucked down seems impossible... especially without any blue smoke.

    The PCV system routes any and all oil pulled up directly into the air intake path, to be burned in the combustion chambers. The amount you described would have filled, plugged, closed off the air tube leading from your air filter to your throttle body. It is not possible for 3qts of oil to sit idly in your air tube or intake manifold... is it? I guess I could be full of sh!t on that one, as I have not checked how much oil can sit in the "second" air box, but it doesnt seem possible for your engine to consume 3qts (almost a gallon, over half of what the engine requires to be full) without blue smoke, or your engine dying from not oil, or your engine dying from too much oil and not enough fuel in the combustion chambers.

    You said you were going 70-80mph, which is normally 2700rpms-ish. Oil does not burn as well as fuel. So when oil is present in the combustion chamber, the engine computer reads it as low-octane fuel, and pulls timing to compensate. This decreases power. Substantially, at that. Were your rpms above 2700 just cruising at 70mph? It seems your engine would have to be working extra hard to make that speed with reduced power.

    Now, back to the ORIGINAL QUESTION... has anyone bought a simple PCV valve, and install it in place of the metering tube? Has anyone drilled out the metering tube to be nothing more than a straw leading to an actual PCV valve? I can understand that a lot of people are not willing to tackle custom mounting a PCV valve into the valve cover where the metering tube goes. But they do make inline PCV valves, I have seent them. Drill out the top and bottom of the metering tube to the fullest size possible, and install the PCV valve anywhere in the hose leading away from the metering tube. Nobody? Anybody?

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting