Diesel Knock Louder than Normal, Hissing Sound

JetttDI@20

New member
Joined
Aug 27, 2020
Location
Charlottesville, Virginia
TDI
Black 2013 Jetta TDI Premium
Hey guys!! I bought my 2013 Jetta TDI a little over a year ago with 60k miles. I’ve put 58k miles on it and for the most part they’ve been trouble free. About 2 months after I picked it up, the DPF cracked and was replaced (under warranty) Was in the shop for almost 2 months. After I got it back, I would smell exhaust coming through my air vents when I was sitting still. I took it back to the dealership, they said they couldn’t smell anything and refused to look into it more unless the CEL was on. I got mad and took matters into my own hands lol. I starting looking around the turbo and pretty much everything they messed with when they did the DPF and found the clamp at the DPF/turbo wasn’t tightened. I could have taken care of it myself but I took it back and made them do it lmao.

Everything was fine for about 2 more months, then I started noticed it didn’t feel as powerful as it was. It just wasn’t pulling as hard. I also started hearing a hissing sound when boost starts to build at lighter throttle. If I get into it more, the hissing goes away. Took it back to them and again they said they couldn’t do anything unless the CEL was on. I have inspected all of the piping from the turbo to the intake and haven't found any signs of leaking, everything seems tight. So I decided to just keep driving it in hopes that the CEL would come on.

Fast forward to now, I’m having a lot more issues. Sometimes it runs great, sometimes it doesn’t. I always fill up at the same gas station (BP) which goes through a lot of fuel so I know it’s fresh. The normal diesel clatter has gotten much louder, but it’s like it hissing noise.. if I push the throttle out of the “sweet spot” it goes away. The other day I was going up a slight incline, it was sitting at about 2k RPM and it acted like I had mashed it to the floor. I could hear the turbo spooling way up and it started pulling really hard with no change to throttle input. I let off the throttle, reapplied and it was fine after that.

Im starting to wonder if the turbo isn’t on its way out. When it’s down on power/hissing at light throttle, the transmission shifts very sluggish, like a worn out automatic and not a DSG. I’m not positive but I think those two problems are related? When it’s doing a regen, you can faintly hear the hissing sound at idle. I religiously maintain it myself, oil changes every 6-7k miles, dsg fluid every 35-40k. Still no CEL ? Have you guys experienced anything like this? This is my first VW, and a diesel at that. I absolutely love the car though, hissing or not ? Sorry this is so long, I just wanted to explain everything the best I could. I’m going to attach links to couple short videos of the clattering sound which you can faintly hear the hissing (ignore my dirty work shoes ?), and one of the regen. I know diesels are louder, but I don’t think they’re supposed to be this loud. Especially when up to operating temp. Thank you guys so much In advance!!


 

k98shooter

Active member
Joined
Jul 8, 2017
Location
Near Atlantic City, NJ USA
TDI
2014 Jetta Sportwagen TDI
It sounds like vacuum leak on clean air intake side of the turbo. Air leak could be the hissing sound, and could be cause behind lower boost pressure and hence loss of power..
 

Daveman1977

New member
Joined
May 18, 2017
Location
Niagara Falls
TDI
2012 Jetta tdi Highline
Hey guys!! I bought my 2013 Jetta TDI a little over a year ago with 60k miles. I’ve put 58k miles on it and for the most part they’ve been trouble free. About 2 months after I picked it up, the DPF cracked and was replaced (under warranty) Was in the shop for almost 2 months. After I got it back, I would smell exhaust coming through my air vents when I was sitting still. I took it back to the dealership, they said they couldn’t smell anything and refused to look into it more unless the CEL was on. I got mad and took matters into my own hands lol. I starting looking around the turbo and pretty much everything they messed with when they did the DPF and found the clamp at the DPF/turbo wasn’t tightened. I could have taken care of it myself but I took it back and made them do it lmao.

Everything was fine for about 2 more months, then I started noticed it didn’t feel as powerful as it was. It just wasn’t pulling as hard. I also started hearing a hissing sound when boost starts to build at lighter throttle. If I get into it more, the hissing goes away. Took it back to them and again they said they couldn’t do anything unless the CEL was on. I have inspected all of the piping from the turbo to the intake and haven't found any signs of leaking, everything seems tight. So I decided to just keep driving it in hopes that the CEL would come on.

Fast forward to now, I’m having a lot more issues. Sometimes it runs great, sometimes it doesn’t. I always fill up at the same gas station (BP) which goes through a lot of fuel so I know it’s fresh. The normal diesel clatter has gotten much louder, but it’s like it hissing noise.. if I push the throttle out of the “sweet spot” it goes away. The other day I was going up a slight incline, it was sitting at about 2k RPM and it acted like I had mashed it to the floor. I could hear the turbo spooling way up and it started pulling really hard with no change to throttle input. I let off the throttle, reapplied and it was fine after that.

Im starting to wonder if the turbo isn’t on its way out. When it’s down on power/hissing at light throttle, the transmission shifts very sluggish, like a worn out automatic and not a DSG. I’m not positive but I think those two problems are related? When it’s doing a regen, you can faintly hear the hissing sound at idle. I religiously maintain it myself, oil changes every 6-7k miles, dsg fluid every 35-40k. Still no CEL ? Have you guys experienced anything like this? This is my first VW, and a diesel at that. I absolutely love the car though, hissing or not ? Sorry this is so long, I just wanted to explain everything the best I could. I’m going to attach links to couple short videos of the clattering sound which you can faintly hear the hissing (ignore my dirty work shoes ?), and one of the regen. I know diesels are louder, but I don’t think they’re supposed to be this loud. Especially when up to operating temp. Thank you guys so much In advance!!


Did you ever get this sorted?
 

JetttDI@20

New member
Joined
Aug 27, 2020
Location
Charlottesville, Virginia
TDI
Black 2013 Jetta TDI Premium
Did you ever get this sorted?
No sir. It still hasn’t thrown any codes, and the dealer told me they couldn’t do anything unless the light was on. I plan to dig in to it when I have some time off. I think it’s an exhaust leak somewhere, I caught a whiff of exhaust up under the hood a few times after a cold start. It’s started to surge pretty bad under load when it’s doing a Regen too. It feels like I’m mashing the pedal to the floor and quickly letting up. Sometimes It will go wipe open until I let all the way off. I know this overboost can’t be good for the rods and such, esp. at lower rpms. It never happens unless it’s doing a regen. When I get time to dig into it I will definitely post my findings!
 
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