Air leak Bad PCV?

[JoeMama]

I am tackling a few different things at once. But I have a very prominent whistle. I understand that it is an air leak. Where are the possible leak points to check for? The PCV Valve is the white top, however I do not know the history of the car. It is a fix and flip. The PCV valve does not have any recognizable logo. I’m assuming and by some matching to a serial number it looks like it’s from Amazon. I pull the big diaphragm off and it does not look torn or cut, looks pretty clean honestly. It has the reinforced diaphragm with fiber weaved in it. All others I blew air through by mouth and hold nice.

I am thinking of just replacing the PCV as a start to find the leak and this is a weak link. However I do not know which version to go with. I do not know if I should go with “AH” black top or “AK” white top. Do I have to update the ecm if I get the AK version? If so can I do that with VCDS? As well as do I need to be “stage 2” oil consumption? If so what parts need to be changed?

Or should I just get the “AH” for the sack of the headache?

Thanks,
JoeMama

[findalex]

If it's a flip car, you never know if the parts are the correct ones.

I recommend calling an Audi dealership, give them you VIN, and ask them to give you the part number that your car needs.

Or you can use this and put in your VIN: https://parts.audiusa.com/

[Smac770]

If it's a freight train whistle, cover the vent hole on the backside of the round cap on the PCV, see if it goes away. If it does, it's the diaphragm.

You don't provide any info to help with parts identification. What model year is this vehicle? What is the info for the software and such in 01-engine section of an autoscan?

[JoeMama]

If it's a flip car, you never know if the parts are the correct ones.

I recommend calling an Audi dealership, give them you VIN, and ask them to give you the part number that your car needs.

Or you can use this and put in your VIN: https://parts.audiusa.com/

I’m the one selling it. That’s why I’m trying to find this leak to get it running 100% with the right parts.

2010 Audi A5 with 75k miles for sale anyone! Lol

Went onto the link and ran my vin and it says the “AH” one.

[JoeMama]

If it's a freight train whistle, cover the vent hole on the backside of the round cap on the PCV, see if it goes away. If it does, it's the diaphragm.

You don't provide any info to help with parts identification. What model year is this vehicle? What is the info for the software and such in 01-engine section of an autoscan?

Definitely would consider it a freight train whistle. I didn’t plug up the hole. However I disconnected the vent tube from the PCV to the intake, plugged my finger in the intake hole and the car runs smooth no misfires and no whistle.

2010 A5 2.0t. Don’t have the full report but there was misfires in all cylinders with a lean code.

[DrGER]

...
2010 Audi A5 with 75k miles for sale anyone! Lol
Went onto the link and ran my vin and it says the “AH” one.

Black top oil separator. OE made by Hengst: https://www.fcpeuro.com/products/aud...em-06h103495ah --g

[Bolshoi]

What's your idle RPM? Is it rough at low speeds? How's the oil fill cap vacuum at idle?

[JoeMama]

Black top oil separator. OE made by Hengst: https://www.fcpeuro.com/products/aud...em-06h103495ah --g

Any aftermarket ones that are decent? ECS has an Hamburg Technic one that seems decent. https://www.ecstuning.com/b-hamburg-...6h103495e~ham/

Any recommendations?

[JoeMama]

What's your idle RPM? Is it rough at low speeds? How's the oil fill cap vacuum at idle?

Not sure of idle rpm’s exact but, has a low idle when it’s warmed up. Definitely rough at low speeds and low rpm’s. Oil cap had little vacuum behind it, would consider it normal since I didn’t have to fight it off.

[Smac770]

Yeah, literally, you just cover the little vent hole on the backside of the cap with a finger, takes tenth of a second to confirm.



You see the hole at the end of the raised tube on the regulator valve cap. Just cover it with your finger. The whistle stops and the engine idles fine again. Because the diaphragm in the regulator valve is torn and outside air is being pulled in when there should be no air flow there at all. If covering the hole did not make a change (when everything is connected correctly), then the leak is not the regulator valve diaphragm, though it might still be something else with the PCV unit.

As for black cap vs white cap, an MY10 would have come with black cap originally. Was it updated to white cap? You'd have to look at the software revision for the 01-engine to know. Or confirm the part number on the front main seal. Looking in VCDS is easier.
https://www.audizine.com/forum/showt...1#post14258030

If you're just selling the thing and the only issue is the torn diaphragm, I'd just replace that using the $30 (or so) Dorman kit and be done with it. Do not use the spring in the kit, use whatever spring is already in the PCV. Or even Audi has a p/n for a repair diaphragm, as noted in the linked post.