Hissing from exhaust

I have an EGR and EGR Cooler delete. When driving my car the exhaust sound will randomly change for a few minutes.

It is straight piped and it changes from a hissing sound to a nice deep tone with a relatively loud turbo whistle (like it should sound always).

I'm wondering if this might have anything to do with the EGR. The valve itself is still on the car but I have blocking plates installed. Any advice is appreciated.

The blocking plates may leak. You still need a gasket on them. I'd check them out.

I recently deleted mine the same you did and as it's gotten colder out mine does the same thing. As it warms up it sounds normal but it'll make that same dull "leaking" noise for a few minutes until then.

'05 Golf TDI, BEW

Edle Sieben said:

I recently deleted mine the same you did and as it's gotten colder out mine does the same thing. As it warms up it sounds normal but it'll make that same dull "leaking" noise for a few minutes until then.

'05 Golf TDI, BEW

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Mine is more often the annoying leaking noise. I found a vacuum leak and fixed that and now it's just constantly that annoying noise. I had my exhaust manifold gasket replaced recently and noticed some brown/dark spots around where the gasket is on the manifold.

The manifold bolts seem tighter than 18 ft/lbs which is what I heard they should be torqued at. Really don't want to break them.

"I found a vacuum leak and fixed that and now it's just constantly that annoying noise."

I'd suggest that you go through the entire vacuum system. Replace all
lines with the proper Gates fabric wrapped line. Check your N75 valve.
Is the vacuum bleed line plugged into the airbox? There's a small white
check valve that could be bad. Fixing one leak and then getting the noise
constantly is the clue in my opinion.