Loud hissing sound during acceleration / 2.0 TDI

Good day.

Well, it seems I've caught it too. I had this weird whistling sound on Wednesday, but I didn't think much of it.
Well, on Friday, I listened more carefully again, and it's definitely making a hissing sound.
And specifically, the sound is like a hiss in the following situation:

during moderate to strong acceleration.
from approximately 1800 RPM.
becoming louder as the speed increases.
It's coming from the driver's side.
On Thursday, I checked the error memory, but there were no entries.

The whistling sound does not occur when the engine is revved while the vehicle is stationary.
The power loss isn't directly noticeable. However, due to traffic on Friday, I couldn't drive faster than 180 km/h.

I listened to the hissing sound with the window open while driving, and it's really loud. It sounds like an air gun.

While driving, I had the feeling that when the engine speed was around 2000 RPM and I maintained that speed consistently, the car would accelerate in a wave-like pattern.

I changed the air filter on Monday, but I don't think it's related to the problem, right?

"I checked the air filter again yesterday, and it seems to be fine. I took it for a test drive, and the whistling sound is still the same. However, after about 5 km, the car went into limp mode (the glow plug symbol was flashing). I pulled over to the right, turned off the engine, waited a few moments, and restarted it. The limp mode was gone, but the symptoms are still present."
Does anyone have any ideas?

Sure, here's the translation:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which translates to "Sincerely" or "Best regards" in English.

Hi,
Your comment

Quote:

I heard the hissing sound with the window open while driving, and it's really loud. It sounds like an air gun

, which basically means: escaping compressed air. You probably have a leak in the charge air system (between the turbocharger and the intake manifold). If the loss is too great, the engine will go into limp mode to protect the turbocharger.First, you should check the hoses connecting the turbocharger to the intake manifold. Make sure all the clamps are tight and that none of the hoses have any cracks. Oil where it shouldn't be can also indicate problems in these areas.
hg
Herbert.

Okay, I was almost expecting that. Actually, I've already checked the piping. Is the intake manifold located directly behind the air filter?

I couldn't detect any oil leaks.

"Could I continue driving for now without any worries? I still have about 80km to drive to work tomorrow before I can possibly take it to the workshop. Or will I damage the charging system by doing so?"

Best regards.

Hello,

"I wouldn't say it's without risk." No one can tell from a distance how large the leak is, but there is a risk of damaging the loader.
Typically, the leak is quickly identified by the oil that is escaping (which is channeled into the intake system by the crankcase ventilation system).

You only need to check the charge air hoses/tubes connecting the turbocharger to the intercooler and then to the intake manifold.

Best regards, Rainer.

Hi,

Quote:

The intake manifold is located directly behind the air filter, or

no, there's the turbocharger, the intercooler piping, and the intercooler in between. Wouldn't it be helpful to get a repair manual as a supplement to your VCDS? Then you'll see more precisely where and how you need to look.
Regarding your last question - the engine is already entering a fault mode. If there is a leak, it will likely get bigger. In my opinion, this requires a repair.
hg
Herbert.

Yes, the repair manual would be helpful. Unfortunately, I don't have it on hand right now; I would need to obtain it.
I only have the Etzold machine at home. I actually wanted to go directly to the workshop after work tomorrow, but the problem is that there's a distance of 80 km between here and there.

I'm going to go check the hoses again, just to be sure.

Best regards.

Okay, so I've checked everything again. And after feeling around in the engine compartment, I suddenly had black, greasy fingers. And then, there it was: a big, fat hole in one of the hoses.
I tried to take a photo. It was a bit complicated, unfortunately, but I hope you can make out something in it.
I believe the hose is located at the very bottom of the turbo.

I guess the hose should be replaced as soon as possible, right?


Best regards.

I also appreciate .
Herbert.

I'm currently doing that. I'm sitting in the workshop and waiting for the result. I hope that's it.
I will report on the results.

Best regards.

Okay, the error has been fixed. It was definitely the charge air hose between the turbocharger and the intercooler.
There was a crack, approximately 40mm long, around the hose.
The car is running smoothly again without any unusual noises, and it feels more responsive when accelerating. The fuel consumption also seems to have decreased. I suspect the crack had been there for a while and gradually got bigger over time.

Cost: €169 / Estimated working time: approximately 1.5 hours.

One more quick question. Could the loader have been damaged by this?


Sure, here's the translation:

"Best regards and thank you for your help!!"

The lower the proportion of full-throttle driving and the less frequent driving conditions with high boost pressure but low engine speed, the lower the risk. Any kind of tuning, regardless of the form, would also be an additional risk in the event of an intercooler leak. To meet the boost pressure requirement, the turbocharger had to work harder and spin faster.

Okay, thank you. So, I haven't done any tuning; everything is original. Well, I actually do full-throttle driving at least once a week, but only when the oil is warm.
Well, otherwise, the charger seems to be working normally. I'll knock on wood that it handled that well.

Good luck...