Whining noise in my new to me 3.0 TDI while parked. PLEASE HELP!!

[bhef]

I picked up a 2014 A6 with ~70k about 2 months ago and since it has developed a whine I hear that is RPM dependent. I have changed all fluids except for front and rear diffs but those would make no difference while car is stationary. It definitely comes from the engine bay and sounds near the front-middle. Subtle at idle and easily heard as soon as I rev it over 1k. In gear the noise remains the same. It was much quieter at first and is now pretty loud.

I removed the serpentine belt and started the car to confirm/eliminate anything connected to it being the source of the whine. Still there with the belt off and even more easily heard.

I'm at a loss as to what it could be.

I will upload a recording of it shortly

 

[bhef]

Link to video/audio of whine:

New video by Brad

photos.app.goo.gl

 

[sloinker]

Pull the oil fill cap and see if the noise changes.

 

[bhef]

Pull the oil fill cap and see if the noise changes.

No noise change at all. Also, no pressure into the engine and no blowby out when taking off or having the cap off.

 

[sloinker]

Should have a slight vacuum I believe. Not familiar with the 3.0 engine. If it isn't in the belt path then.... water pump, timing components, torque converter, the list goes on. Sorry I was of no help.

 

[bhef]

Water pump is on the serpentine belt with this one. From what I've read it's unlikely it's the torque converter, but it may be the turbo or cp4 fuel pump. I really don't know how to diagnose those besides checking the turbines for damage and shaft for play. Thanks for your perspective. I appreciate it nonetheless.

Anybody else who has any insight to contribute would be greatly appreciated.

 

[commedeschatons]

the hpfp can make a noise like this too FYI.

 

[bhef]

That's what I'm thinking it is at this point as turbo shaft play is non-existent and impellers are in good shape on compressor side at least.

Is this a sign that it's failing? Is that noise normal?

 

[TurboABA]

So that video was with belt off?

 

[bhef]

The video had it on, but it was exactly the same with the belt off. No difference

In the meantime I ordered a disaster prevention kit for the cp4 hpfp that will be here soon and fitted ASAP to avoid a car down for weeks+ scenario

 

[TurboABA]

Might want to do a carb clean and pressure test your coolant system once you have the intake off if you're going that deep into things.

 

[bhef]

Definitely going to carb clean. I have to take the manifold off to get at the fuel lines to install the kit. Getting the coolant system pressure tested is a good idea too. Thanks!

 

[TurboABA]

Get ready to do your oil cooler seals when you fail the pressure test

 

[bhef]

Yeah it has a very slight oil leak there already confirmed with boroscope into the valley however, no noticeable oil level reduction after 4k miles.

Still at a loss. Sound definitely coming from turbo/hpfp area.

Would the PCV/breather system make this noise or would a failing/leaky/broken coolant diverter valve vacuum diaphragm make this noise? Can't think of anything else in the area that would make this noise

 

[TurboABA]

Sound definitely coming from turbo/hpfp area.

I'm terrified.... and it's not even my car!

 

[commedeschatons]

vacuum coolant valve wont make such a noise and it certainly wont change 1:1 with RPM.

I still think this sound could be normal like HPFP pumping sound NOT Turbo. turbo shaft speed is not going to scale directly to enginerpom

 

[TurboABA]

When's the last time the PS system was flushed? I know you said it's coming from the rear, but that's starting to sound like the PS pump to me. What's your fluid look like?

 

[bhef]

When's the last time the PS system was flushed? I know you said it's coming from the rear, but that's starting to sound like the PS pump to me. What's your fluid look like?

I don't have a PS pump its electromechanical

 

[bhef]

vacuum coolant valve wont make such a noise and it certainly wont change 1:1 with RPM.

I still think this sound could be normal like HPFP pumping sound NOT Turbo. turbo shaft speed is not going to scale directly to enginerpom

That's a bit of a relief. Why would it start to whine when it didn't a few thousand miles ago?

 

[TurboABA]

I don't have a PS pump its electromechanical

Shame on me.... I haven't even checked mine to see it doesn't use the same system as my Touareg... That's what I get for assuming.

 

[RustyBearing]

If it's any consolation, I think it sounds very similar to my 2015 Q5 TDI. It always has a slight whine and changes with RPM, but not really noticeable any speed over 15mph. I always thought it was typical diesel noises. I'd try replacing the fuel filter and using some LM diesel purge additive.

I also had a 2014 Q5 TDI before that was probably on its last leg of the fuel pump, it was definitely louder from the interior. The sound inside was a tiny electrical whine and could be heard priming when the car was powered on with engine off. Although, I do not hear that same noise in my 2015 with similar mileage now.

Should I be concerned too?