Hello,

 

My 2008 Octavia vRS TFSI has developed a squeal/screech. The noise only happens on throttle lift off as the revs drop, usually specifically from around 3k to 2k rpm, and is not related to speed as it can be in any gear. It only happens when the car is fully warmed up, it has never made the noise when starting and it does not make the noise at idle (making it tricky to pin point where the noise is coming from). The idle seems to be fine, no erratic movement in revs and the car is driving fine. The turbo pick up feels exactly the same as before the noise started and it never makes the noise on rising revs, only falling revs. No noticeable loss in performance. 

 

I thought at first it was the aux belt slipping so I replaced the belt, but the noise described above was still present. I then replaced the aux belt tensioner, but no joy and the noise still happens. It really sounded like belt slip to me. I've tried with aircon on/off but it doesn't seem to make a difference.  

 

Has anyone experienced this or have any suggestions to what it could be? 

 

I've been searching through the forum and notice that PCV seems to be a common issue. Could a PCV valve on the way out make a noise like this? I did notice a small amount of oil on underside of oil filler cap. 

 

Thanks.

 

 

 

Possibly a torn diverter valve diaphragm? Does the car pull well all the way through the revs?

When my D.V tore I lost boost over around 3.5k

Possibly a torn diverter valve diaphragm? Does the car pull well all the way through the revs?

When my D.V tore I lost boost over around 3.5k

 

Hello,

 

The car is pulling fine through the full rev range. The diverter valve was changed about 18 months ago. Do they go regularly?

 

Noticed today that it did a very short squeal when I turned off the engine, which is a new sympton. I think I read somewhere that this means possibly PCV...but now I can't find that thread!

Hi mate.

A simple check for the pcv being faulty is to pull the oil cap off and if the car runs rougher then it's ok but if it runs the same as when it's on the pcv Is faulty.

I doubt it's the D.V if it's been replaced already but it depends on the part number that was used.

I've not had the pcv fail personally so I'm not 100% on the symptoms.

Have you checked the alternator pulley?  Mine seized up causing a squeaky belt.

How did you get on tracking it down? I've got a similar issue will make another thread tomorrow.

I think it's just the boost pressure getting released? Mine does it

I'm thinking it is the PCV valve after all, but will know for sure once replacement arrives and I fit it at the weekend. 

 

I don't think it is related to the aux belt or pulleys at all now as it gives a squeal after the engine is off for a few seconds, and also the revs have started jumping a bit when idling. The oil cap is really difficult to take off when idling and I read that this is a good indicator of a bad PCV.

 

I'm hoping it is the PCV just so then it is resolved as I'm slowly replacing the engine part by part at the moment.

A replacement PCV was fitted at the weekend and after a few drives all symptoms have vanished. Car is running much smoother, especially at low revs. 

 

I used this part. http://www.ebay.co.uk/itm/06F129101R-OEM-Quality-PCV-Valve-Seal-for-Audi-Seat-Skoda-VW-2-0-TFSi/132004079601

Good result and good to close out the thread for subsequent readers.

Edited 28 November, 20169 yr by TheClient

Well after a week of symptom free driving the whistling is back with a vengeance.

I've compared the noise with all the youtube videos I can find and all point towards pcv again. If I pull the dipstick the engine continues to idle smoothly, it sucks from the dipstick and the noise goes away. As soon as I replace the dipstick the noise comes back.

Don't really know how it could have gone again so soon...other than I bought aftermarket instead of genuine. Tempted to fit a pcv delete kit now.

I'm planning to replace the PCV again, this time with a genuine part. (fingers crossed it was just a duff non-OEM one).

 

Does anyone know of reasons why the PCV fails, other than the part being a weak point in itself? I am just curious if I have other problems causing the PCV to go.

 

Thanks

New part arrived, genuine part from an Audi garage this time. 

 

I read somewhere that blowing through the inlet side of the PCV should not be possible. The new genuine part, resistance, can't blow thorough at all. Old part (the non-genuine one I fitted last week) there was no resistance at all, literally nothing stopping me blowing air through it.

 

A couple of journeys made to test drive and all symptoms have vanished again so at least I know it is the part causing the noise and revs issue. Much smoother drive. No erratic idle.