Help Please?

[Charliemk6]

Hi All,

My 09 MK6 has been suffering with rough idle and vacuum issues (revs will stick and drop stick and then return to normal).  Car shakes and splutters on idle.

I was told it was the PCV - so I have replaced this twice now.. (first one I got wasn't OEM so thought could be faulty) but to no avail.

DV was replaced recently so do not think it is this.

If I disconnect the inlet pipe and plug the end that is circled with my finger the car idles as normal, so this rules out plugs and coils.  But does anyone know what else this could indicate?



I've checked all the pipes to the PCV and all are in good order with no leaks.

Any assistance would be appreciated as I'm losing the will to live!

**EDIT** Turns out I have an oil leak from the Rear Main Oil Seal.  So this is the culprit.
Looks like It's gonna cost me a small fortune too. 

Great after just spending over £700 on servicing last month.

[topher]

First step is a smoke test to check for intake leaks which might highlight something obvious. I've seen 3 or 4 of these now have similar symptoms being caused by a leaking crankshaft seal behind the flywheel, do you have any signs of oil leaks underneath where the gearbox meets the engine?

[Snoopy]

Once the PCV fails and you keep using the car the pressure finds the next weekest link to release, sadly this is the rear main seal as you found out.
I was told there are a few aftermarket rear main seels that are a better design than the OEM it may be worth a bit research to find out more info on those.
Also depending on mileage you may want to think about clutch replacement if its a manual while the box is out.

[Charliemk6]

There is a very slight oil leak, the bell housing is covered so def coming from the rear seal.

I'd hoped this was just due to the pressure from the faulty PCV and hoped it would return to normal once this was changed.

Think the faulty PCV has knackered it.

The symptoms did go away for a while but have returned which is weird

[Snoopy]

The rear pipe to the PCV can splits or not reseal well. Did you change it or reuse it? Check for oil below it.

[Charliemk6]

Hi Snoopy,  I checked all of the pipe work and it seems ok although there was some oil at the back where the air filter pipe connects but all seemed to be connected fine?

Really hoping its not the rear seal, been told if it is there is a good chance it will have contaminated the clutch and the flywheel will need to be changed too - Quoted £1200....