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Help Please Changing PCV

Crowdie Jul 15, 2019

  1. Crowdie

    Crowdie New Member

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    Hey,

    I bought a B8 S4 two weeks ago and unfortunately failed to pick up an oil consumption problem (private sale). Seems like I'm getting through 500ml every 300 miles at a guess (short journeys)... it might not be quite so bad, I've just ordered a dip stick to verify the MMI readings (assuming 1 litre between max and min).

    After some research it seems the PCV is a common failure, my car is 2009 so I'd expect it's likely this. The car does hesitate when starting from cold which I believe is another symptom of the failure.

    I have taken out a warranty but unfortunately cannot claim for the first 90 days.... with this rate of consumption I'm tempted to replace it myself, the disadvantage being it would have to be the original part and not the revised part as I can't do the ECU update.

    I've read through a few tutorials on changing the thermostat which seems to involve a similar amount of work and was hoping to clarify a few things.

    How difficult is it to remove the supercharger belt / is a special tool required?
    Would the coolant need bleeding again after it's been removed?
    What seals / gaskets need replacing once the SC has been taken off other than the gasket around the PCV?

    Generally any tips would be hugely appreciated.

    Thanks
     
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  3. rum4mo

    rum4mo Well-Known Member

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    I'd think that the supercharger belt will still be the original so better to replace it, it has the normal tensioner that you crank back to slacken the belt. Probably better to move the front out to the service position and change the auxiliary belt while you are in there.
    PCV, I'd expect that the only version that you could buy would be the latest and it was changed for a reason, then get a local proper VW Group Indie to update the S/W but check with them first.

    I worry lot about this and the thermostat, if I was brave I'd preempt all these possible trouble areas at one go.

    If you are serious about doing work on this car, why not buy a workshop manual from maybe easymanuals, I bought one recently and also one for a 2015 VW Polo as that is currently the only way to get hold of all the torques processes etc. Signing up for Erwin is another option which if you became efficient in using it would cost less than the easymanuals option. I just bought their DVD option and dumped it on a stick for ease of use.

    Edit:- I think that Audi suggests that you bleed the system at quite a few points, also I'd be buying new gaskets for the supercharger<>head joining points, no point in messing up for a few quid.
     
    V6_Man likes this.
  4. Dippy

    Dippy Well-Known Member Team Monsoon Audi S5 Black Edition

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    Inspect the crank pulley whilst you are at it - the damping polymer is known to degrade - in the worst cases catastrophically.
     
    rum4mo likes this.
  5. Crowdie

    Crowdie New Member

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    The car has some pretty extensive work carried out in 2017 where the engine and gearbox were removed from the car. It had:

    Valve Cover Gasket both banks
    Timing chain top cylinder head covers removed, sealed
    Bank A vac pump replaced
    Waterpump
    V fan belt and supercharger belt
    Heater valve

    Shame they didn't do the thermostat at the same time. Think this covers most of the belts (not actually sure what the V belt is), I'm looking to go forge pulley and remap in the near future anyway although this is the top and not bottom?

    Hadn't realised that there were manuals worth having, they were a bit poor on the Renault so never bothered. I'll take a look into them, cheers!

    Having another intermittent fault - car likes to start running on 5 cylinders randomly. Happened the first time and codes said cylinder 1 missfire. Thought I'd be clever and swap the coil over to 2 and see if it followed. Happened again just now and its moved to cylinder 3... not what I was expecting. Ruled out injector and the coil as its moved. Wondering if maybe the PCV is causing this too.

    Edit -

    Codes I'm getting are P0303 which is easy enough, but also get 06352 and 07948 which Carista doesn't know the meaning of and can't seem to find anything online. The first time it happened I had cylinder misfire 1, 06350 and 07948.
     
    Last edited: Jul 15, 2019
  6. rum4mo

    rum4mo Well-Known Member

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    V belt will be old school slang for the auxiliary belt which in many years gone by was a V belt, nowadays it is a micro veebelt, otherwise known as a multi ribbed belt.

    Edit:- Carista can get stuck at times in giving a suitable fault code definition, and will at times hand out a crazy implausible definition, VCDS does not have that limitation.
     
  7. Crowdie

    Crowdie New Member

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    Ahh ok that makes sense, at least the belts are done then. I've got a friend who has VCDS so I'll borrow that for a bit, the codes were only pending so have cleared themselves which is frustrating.

    Having looked around at a few tutorials, am I right in thinking the only parts I will need to do this are:

    PCV
    6 X Intake Gaskets

    And there are no special tool requirements?
     
  8. rum4mo

    rum4mo Well-Known Member

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    There must be better or more knowledgeable people in here than me to confirm that as I have never ever carried out that task, but that sounds like what you will need.
     
  9. PenttisHSR

    PenttisHSR Active Member Audi S4 Audi Avant Owner Group Manual

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  10. Crowdie

    Crowdie New Member

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  11. PenttisHSR

    PenttisHSR Active Member Audi S4 Audi Avant Owner Group Manual

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    As well as the thermostat and water pump, it seems that it's also worth replacing the two hard plastic coolant pipes whist you are in there. They go brittle with age and with all the wriggling to get the thermostat & PCV Valve out, it's easy to crack them, apparently.
    Make sure you align the "flaps" up too when refitting the inlet manifold, otherwise it will throw a code/not run right.
     
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  13. PenttisHSR

    PenttisHSR Active Member Audi S4 Audi Avant Owner Group Manual

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    POLY-V Belt ? (poly meaning many) :icon thumright:
     
  14. Crowdie

    Crowdie New Member

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    Definitely tempted to do the thermostat whilst I'm most of the way there, though it does add to the long list of things to do. Water pump has recently been changed as well as a "heater valve" so OK on that side of things.

    Ordered the suggested coolant pipe mentioned in the tutorial. Managed to get a quote of £75 to update the software to the newer version which reduces the pressure.

    Also ordered a dipstick to verify the MMI readings as one minute its full then its empty.... need to rule out a duff sensor.
     

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