TDI whoosh sound gone

Hi I know what causes the whoosh sound we all love, and I've been straight piped and enjoying it for a couple years now. But I almost never take the highway, my commute just doesn't require it. That being said, after taking the highway for the first time in a while, cruising at about 70mph (+/- 5 at times) I no longer hear it.. Lower rpms it seems to spool down slow enough to catch it, but I mean this ol girl used to sound like she was trying to do a Rick flare impression... WOOO!!! Loud as all hell. How all I hear is the turbo spool down.. Almost sounds quicker than normal too. Would this be because of sticky vanes? It's a stock VNT15. There is no shaft play whatsoever and the bearings spin freely, just checked because I was nervous. All I did was feel cold side of the turbo though.. Should I pop off the downpipe and throw in some oven cleaner? Would brake clean also be too aggressive? Thanks!

brake cleaner wont do jack
oven cleaner works so darn well.
i would test the actuator though, might be a bit sticky, if it fails the test, then your n75 valve might also be on the the way out as it can suck up bits of failing actuator rust.
food for thought.
start with some oven cleaner, have a garden hose nearby ready, that stuff will mess up paint and bare aluminum if left to soak on it.

Mongler98 said:

brake cleaner wont do jack
oven cleaner works so darn well.
i would test the actuator though, might be a bit sticky, if it fails the test, then your n75 valve might also be on the the way out as it can suck up bits of failing actuator rust.
food for thought.
start with some oven cleaner, have a garden hose nearby ready, that stuff will mess up paint and bare aluminum if left to soak on it.

Click to expand...

So testing the actuator shows a bad n75? Not a bad actuator? Also, what's the best way to test it?

Tsasso said:

So testing the actuator shows a bad n75? Not a bad actuator? Also, what's the best way to test it?

Click to expand...

You move the actuator though it's stroke with fingers or a tool if you can't reach it.
It should move freely without roughness or sticking. Just moving it a bit may free it.
If it moves freely see if it holds vacuum with a MityVac.
The N75 is easily tested and can be cleaned out if dirty with Dust-Off or low pressure air.

flee said:

You move the actuator though it's stroke with fingers or a tool if you can't reach it.
It should move freely without roughness or sticking. Just moving it a bit may free it.
If it moves freely see if it holds vacuum with a MityVac.
The N75 is easily tested and can be cleaned out if dirty with Dust-Off or low pressure air.

Click to expand...

And if it doesn't move at all?

When you first start the car you should be able to see directly down to the actuator and watch the actuator suck in. Have some one else start the car so you can view this. If it does not suck in then pull the vac line for the actuator and pull vac with a mighty vac. 3hg for the arm to start moving and around 17hg for the vanes to fully close. If that is correct then the n75 probably needs cleaned or replaced. Although if most of this things were going wrong the car should throw a light for boost deviation.

All that the OP said was that he couldn't hear the "Whoosh" (Whatever that is...), not that the car was performing poorly. Our '01 golf has a cat back Buzzken exhaust and when I'm driving it around town, I can hear the turbo spooling all of the time, because the sound is resonating off of walls, other cars, etc., etc. Not so much on the highway. If it ain't broke, don't fix it...

Those actuators rust out so badly in the northeast! It might be missing the bottom half of it, but look ok from above. Feel around or climb under the car with the wheel off on the passenger side and shine a bright light in there to check things out.