Help Please Changing PCV

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

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.

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?

PenttisHSR said:

There are some useful write-ups over on Audizine.
Here is one of them......... https://www.audizine.com/forum/show...iteup-pics-and-tips?highlight=pcv+replacement

Click to expand...

Ahh that's perfect, I hadn't come across that write up before. Thanks for sharing, highlighted some more parts and tools I need to order. Such a daunting job, hoping its not as bad as it looks when you get stuck in.

PenttisHSR said:

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.

Click to expand...

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.