Temperature dropping - turbo insanely loud.

AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
So, this is my first TDI and during the summer and fall days the turbo was almost unnoticeable(minus in between shifts). I have a VNT-17 almost brand new from the summer along with all upper, lower, and intake Kerma hard pipes. So, all that being said I just left work tonight and let it warm up a few minutes and piled away.. Sounded mostly normal until I hit the on ramp and got under heavy boost and my god... It sounds like it's going to suck the hood in. Is his typical?? I've checked all the pipes for leaks and I'm still pulling a solid 20-22psi under WOT. I've owned plenty of FI turbo cars, but never really experienced anything like this.

I also running the KERMA SMIC along with a .3bar map of that helps any. Should I be worried??

EDIT: Also, running a "cold air" drop in filter. Lastly, the noise stays the same even after fully warmed up.
 
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Mike_04GolfTDI

Top Post Dawg
Joined
Nov 19, 2003
Location
Richmond, BC, Canada
TDI
Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
This cold air filter, is it one of those cone filter type things like people put on their mom's old Toyota Camry after she dumps it for a RAV4?

If it's one of those, I'd say that's the first thing to look at for your noise issue. Maybe try the original air cleaner assembly and see what happens.
 

Mike_04GolfTDI

Top Post Dawg
Joined
Nov 19, 2003
Location
Richmond, BC, Canada
TDI
Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
Oh. That's probably not causing the noise problem then.

If the noise started suddenly then I'd say something has changed. For example, did the lower engine cover fall off? That would let out a lot of noise.

Or maybe a boost pipe is leaking somewhere.
 

AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
Oh. That's probably not causing the noise problem then.

If the noise started suddenly then I'd say something has changed. For example, did the lower engine cover fall off? That would let out a lot of noise.

Or maybe a boost pipe is leaking somewhere.
I've actually removed all the covers just for ease of access. I've checked all the pipes for leaks and I'm still holding boost. I'll give it a once over again today since its day light out. The few times I had major issues with boost leaks either caused zero boost and MASSIVE amounts of black smoke. I'll check it and report back... Very odd though.

Update: All the pipes are super solid and seems to be zero leaks. Bleh, guess I'll just chalk another one up to the MKIV gods.
 
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AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
Did you check your egr assembly and intake manifold to make sure they are tight? That could cause some noise.
I have a complete EGR delete I put on a few months ago. Intake as well.. Everything is torqued to specs. I'll give it a go this afternoon to work with warmer temps and see what happens. If it's normal I guess I'll just go with believing this car really really likes cold weather.
 

AnotherPerson

Veteran Member
Joined
Oct 24, 2015
Location
New Orleans
TDI
1999 Beetle
Is the sound coming from the exhaust or you just hear it inside the car? Under boost when driving I had a extremely loud whistle and it turned out to be the nipple on the vacuum pump. The mounts were flexing and it was opening up. Have the car idle and give a small push on the vacuum pump nipple, not too hard. If it whistles than you know what it is. Some silicone will usually seal it right up.
 

justynd

Well-known member
Joined
Aug 16, 2015
Location
Central WI
TDI
02 Golf, 04 wagon, 00 Golf
Boost leaks make very funny noises. On bigger diesels at work (12L) a small common boost leak under full load makes the shriek of a dying rabbit and is unobserved by the ecm and unnoticable on a gauge but one turn off a hose clamp cures it every time.

Try soapy water at connections like looking for a tire leak
 

AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
Same damn issue today so it's not temperature issues. It sounds like a very loud sucking noise even under a few pounds of boost I can clearly here it from the passenger side around the SMIC area it seems. If I had a boost leak shouldn't I be bellowing out black smoke and not even making boost?! I guess I'll jack it up and tear it all apart on my day off. All the couplers are brand new and pipes even... Bleh!! Hopefully tomorrow I'll find the issue and report back.
 

AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
Welp, dumb stuff guys - I woke up this morning and remembered I had street parked my car for the first time in basically ever... Two *******s pinned me in so I was cutting the wheel back and forth a few times and remembered that the new wheels I have are 9 wife instead of 8.5... So sure enough the tires rubbed just enough to knock the pipe lose.




As you can see where the tire was rubbing... So dumb. Anyways, re- angled the pipe better this go around and snugged everything down to 600000 ft lbs on the two bolt clamps. Live and learn I suppose.

Edit: Still not fixed guys. Went for a test drive and it's just insanely loud whooooooosh noise the entire time on throttle. Any ideas?? Turbo just **** the bed already?!
 
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AHouseOnFire

Active member
Joined
Jul 3, 2016
Location
Colorado
TDI
MK4 Jetta
Oh my god guys - a few beers later and scratching my head and calling Kerma to cry... This is what I have found. The most obscure clamp in the mix... So, apparently a small leak PRE intercooler won't cause any smoke screens and apparently still hold boost as normal.... so... For anyone that has this noise and related issues with zero smoke... It has to be PRE intercooler leak. Hope this helps someone way down the road.

 
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rwolff

Veteran Member
Joined
Mar 10, 2002
Location
Lesser continental mass, Tosev 3
TDI
None yet
On bigger diesels at work (12L) a small common boost leak under full load makes the shriek of a dying rabbit and is unobserved by the ecm
IIRC, the only diesel available on the Rabbit was a 1.5L (wouldn't be able to fit a 12L under the hood), can't recall if it was turbocharged or normally aspirated (in which case it wouldn't have any boost to leak), and it was a mechanical unit (no ECM to observe the problem).

Also, I wouldn't consider 12L to be a large diesel.:p
 
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