Good evening everyone, 

I've had this noise coming from my engine bay for a few months now, only showed itself every once in a while and I could never track it down until tonight.

Part number on it (1k0906627b) suggests its an N75 valve and its responsible for controlling boost? 

Some vw based forums suggest its possible to clean these? Would it be worthwhile to try cleaning it first or is replacement the best way forward? 

Should add, never went into limp mode, never got a code related to it (I only ever get a P0101 code coming up once in a while, have since I got the car. Never felt any difference in the car and it would go away on restart.).

 

If you're certain it's faulty then simply replace it, they're not very expensive.

 

You can't clean it because they can't get dirty so I've no idea what that nonsense is about.

13 minutes ago, sepulchrave said:

If you're certain it's faulty then simply replace it, they're not very expensive.

 

You can't clean it because they can't get dirty so I've no idea what that nonsense is about.

Its the noise thats making me think its faulty more than anything.

Had an inkling cleaning it was pointless, thanks.

Took ages for a replacement one to arrive but I have fitted it, noise is gone and its running a lot better.

Theres some weird gunk on the ports of the old one, how it got there I don't know.

On 27/02/2022 at 23:40, DieselMonte said:

Its the noise thats making me think its faulty more than anything.

Had an inkling cleaning it was pointless, thanks.

Mine makes the same noise. Runs fine when cool but idles lumpy when warm. Squeaky click coming from same part. 

Mines been running much better since I put the new one on. I cleaned out my old one though not too long ago, as I was curious if anything was stuck in there. 

Ran compressed air through it first, barely any air coming through the other port. Sprayed brake clean through it and a lot of black gunk came out of it.

Ran compressed air through it again and immediately clear it made a difference. Proper "click" sound when starting and stopping running air through it, and more air going out the other side of it.

 

Chances are I could have gotten away with cleaning my old one, but now I can use it as a spare "just in case"

36 minutes ago, DieselMonte said:

Mines been running much better since I put the new one on. I cleaned out my old one though not too long ago, as I was curious if anything was stuck in there. 

Ran compressed air through it first, barely any air coming through the other port. Sprayed brake clean through it and a lot of black gunk came out of it.

Ran compressed air through it again and immediately clear it made a difference. Proper "click" sound when starting and stopping running air through it, and more air going out the other side of it.

 

Chances are I could have gotten away with cleaning my old one, but now I can use it as a spare "just in case"

 

That's very interesting, I'd love to know where the black gunk is coming from, tandem pump oil leak?

I've no clue to be honest how it got in there, you can see some of it in the photos of the old one I posted before. Probably worth it for me to take off the new one and see if it now has the same gunk on it.

I've never noticed much oil usage though and its running absolutely fine. Noticed a fair bit of oily vapour coming through the CCV, Suppose thats normal though.

Common issue. Mine was like that for about 2 years but never caused rough idle. Replaced with new OEM and sound stopped but never noticed a difference. 

Hi @DieselMonte

 

Absolutely delighted to have found this because I’ve got the same issue right now! 

 

How hard was it to replace the part?

 

Cheers,

1 hour ago, OBR said:

Hi @DieselMonte

 

Absolutely delighted to have found this because I’ve got the same issue right now! 

 

How hard was it to replace the part?

 

Cheers,

Stevie wonder could do it.

5 minute job tops.

Only thing that might be annoying is the vacuum lines being a bit annoying to get off.

They should slide off but you might need something to wedge between the pipe and the bit on the n75 itself. Should loosen it up enough to come off.

Just found this thread and it is exactly what is going on with mine! Where did you buy the replacement from as I am finding it hard to locate anything that isn't on Ebay or Amazon and not sure I can trust those!

On 12/03/2025 at 17:19, klang180 said:

Just found this thread and it is exactly what is going on with mine! Where did you buy the replacement from as I am finding it hard to locate anything that isn't on Ebay or Amazon and not sure I can trust those!

Easy got online but I wouldn't, went down that road and they don't last lmao. Get a pierburg one in a motor factors. I had some real weird driveability problems with cheap ones. Had ones where it wouldn't boost till 3k then shoot off. I think at the minute I'm using one from my parts car.

Thanks for this. I did buy it online but got it from a reputable seller and not just eBay or Amazon, as tempting as those are.