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Alloytecs don't have a traditional PCV valve?

Discussion in 'VZ Holden Commodore (2004 - 2006)' started by WL2005HBD, Aug 24, 2013.

  1. WL2005HBD

    WL2005HBD New Member

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    Hey guys,

    Been searching high and low for a replacement PCV valve for my WL as I have an oil issue that I narrowed to the PCV.
    I can't find any part numbers on it, and when I ripped off the valve cover, I just found a metal tube that wasn't removable (see pic below).
    Also seems a lot of Cadillac forums talk about the lack of a spring loaded PCV check valve, apparently it just meters the flow because the little nozzle is so small.

    [​IMG]

    Can someone verify this, and if that's true, why in my dual catch can set up, is my pcv side catch can completely clean barely even smelling of oil, but my breather side is overloaded with oil??

    Thanks
     
  2. richardpalinkas

    richardpalinkas Blown Alloytec

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    There's 2 types of pcv valves, one has a spring inside and is similar to a check valve, the other uses an orifice, a small hole that allows a certain amount of flow though restricted by the size of the hole.
     
  3. richardpalinkas

    richardpalinkas Blown Alloytec

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    Can you suck or blow through the pcv valve?
     
  4. WL2005HBD

    WL2005HBD New Member

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    Nope
    It must be clogged with crap.
    Gonna take it to a mechanic to have the valve covers taken off and the pcv cleaned, coz in my dual catch can, the breather side filled with oil in a fortnight and the PCV side didn't even smell of oil
     
  5. richardpalinkas

    richardpalinkas Blown Alloytec

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    From memory, you may be able to get some vice grips on it and wriggle it out, then just clean it out, but be gentle so u dont break anything
     
  6. diysv6

    diysv6 Member

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    Hi WL2005HDB,

    Have you found out if the PCV valve is a check valve design (spring loaded ball valve or similar) or is it a through tube with a small metering hole? Is it removable from the tappet cover whilst the cover is bolted down, or is irreparable damage done to the plastic tappet cover?
    Thanks.
     
  7. diysv6

    diysv6 Member

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    Further PCV Valve research:

    I have done some looking around the internet and the fixed orifice PCV is a permanent fixture (not removable or serviceable) in the HFV6 tappet cover with no moving parts, (just a small hole 2.5mm diameter in some posts). The small metering hole limits the amount of oil that is sucked into the inlet manifold, hence reducing some oil consumption cf the old spring loaded PCV valve units. However, when the fixed orifice is blocked, the crankcase pressure pushes oil vapour back through the inlet/intake to the manifold, hence the oiled up throttle body and the filling catch cans etc.

    The PCV valve is factory set into the tappet cover and only requires cleaning - in the US some service books suggest 60K kms interval. It stops oil in the intake air tract and is very common in many engine designs. Japanese European US and now Holden. One post for a 3.6 HFV6 suggested that a new tappet cover gasket/s is available in the USA which limits the oil spray getting directly into the PCV assembly. Something about a reluctor wheel throwing excess oil at/into the PCV valve area.

    Cleaning instruction is to wet a pipe cleaner with carby cleaner and slowly clean out the blocked valve body. Also clean the vacuum lines back to the inlet manifold. One Chevrolet workshop fix was to spray the PCV valve with carby cleaner - Kreen. Some contributors then changed the engine oil. (Maybe do the clean just before a scheduled engine oil change?)

    At least this saves lifting the tappet cover. Some posts assert that the air-cleaner element be kept clean (to stop excess air flow from the crankcase) and fitted such that there are no air leaks allowing dust to enter the intake tract to the engine.

    I have given a google search sequence to a copywrited Book extract in which the PCV is discussed and its contribution to oil build-up in the inlet tract is also discussed.

    Try google books. Then search on
    cleaning a fixed orifice pcv valve cengage learning
    Then go to p1023 for the practical solution with the pipe cleaner.
     
    Last edited: Sep 21, 2013
  8. diysv6

    diysv6 Member

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    Follow-up fixed orifice PCV Valve & engine oil in the inlet tract.
    I did some work on the inlet system of my 2004 SV6, and thought I would pass on my findings. Sorry if the epistle is a bit long.

    Engine has done 97K kms. Routine checking the dip stick indicated very little oil consumption since the last oil change 6 months back. I had replaced the paper air filter a year ago, and cleaned the Throttle Body (TB) and MAF sensor about 8 months back with CRC MAF cleaner.
    The air cleaner element was reasonably dust free, no water or obvious dust discoloration, but had pieces of solid matter, grass, insect wings etc. trapped in the folds of the paper filter. Held it up to the sun and the filter paper was very clean.

    I would have had about equivalent to 4-5 drops of engine oil spread though the inlet tract. I have never wiped out the inlet track, so the oil is basically from 2004 - unless the Holden dealer cleaned it during their warranty services. An oil mist at the PCV inlet pipe join and a slight oil wetness at wall of the 90 degree bend just before the TB entry. I purposely stood the inlet tubing vertical for an hour or so, to check if any oil had found its way into the tuned intake stub, and if so, it could drain back. No oil there. Went through my mind to drill a drain hole at the lowest point at the end of the stub and fit a self tapper screw with silicone sealer as a quick test for a blocked up PCV valve. Is it a convenient Catch Can? I left the MAF unit in its plastic housing and sprayed it with the MAF cleaner from both directions. I didn't get any solid matter, so I think it was fairly clean.

    The TB was fairly clean, any traces of "soot" were sticky but not oily wet. I cleaned it in situ with a lint free rag wet with MAF cleaner. I had read somewhere not to spray the MAF cleaner directly into the TB shaft bearings as it could get into the electronics of the TB if the O-ring seals are worn. The PCV valve in the 1-3-5 tappet cover was my next checkpoint. The top hole is > 1.5mm and < 2.0mm in diameter. I tried a pipe cleaner, (dry with no solvent on it) through the top hole wriggled it around and it came out dry, no oil wetness or any gunk type deposits. From the top hole to bottom of the PCV valve, it is about 42mm deep. I next tried a piece of copper wire about 1mm diameter into the top hole and moved it around until it went through the bottom hole into the camshaft area. It was not impeded by any springs or valve system as in the old design of PCV valves. The copper wire came out virtually dry and not a trace of any contact with any oil sludge. Consequently, I did not run carby cleaner or MAF cleaner through the PCV valve into the tappet cover. If I had, I think I would have cleaned it with carby cleaner, with the engine hot and running to ensure maximum dilution of the cleaner, lubrication to the camshafts/valve gear, and then given the engine an oil change soon after. Maybe a teaspoon of carby cleaner in 6 litres of hot engine oil would evaporate quickly with no real damage done? I don't know whether the carby cleaner would drip directly onto camshafts or valve gear when it is sprayed through the PCV valve. Perhaps a reader can clarify this?

    As a further check, I pushed an 8mm ID plastic tube over the PCV outlet and blew through it, the resistance was about what I expected considering the small diameter of the PCV valve metering holes. My last check was to have the engine idling, and block the 2-4-6 tappet cover PCV outlet with my thumb for about 15 seconds, and feel for a gentle vacuum being present. A "breathing" noise is evident when you remove your thumb as air rushes into the crankcase. This vacuum indicates that the PCV is working at idle speed. Maybe Holden has a figure for this reading? When a motor is not normally aspirated (turbo etc) or has long duration overlap cam/s fitted, or has shot rings, or leaking valves etc. this vacuum could be very much reduced, and Catch Cans may be required at both tappet cover PCV outlets to collect the combustion blow-by and oil mist/particles occurring during normal engine RPM. Some contributors suggest disconnecting the negative battery terminal for a period of time to allow the ECM to clear its fuel management data. I disconnected the negative battery terminal for about an hour. Took it for a test drive. Ran smoothly from start up.
     

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