Turbo Howl - fixed

ChefDJ

///Member
A while ago (two years almost) my car started making a really loud howling noise in the engine bay on cold starts, when accelerating slowly between 1200rpm and 1500rpm. It would disappear as soon as I had revved past the 1500rpm mark and wouldn't come back until the car had cooled down again. I asked about it on the forum before and took it to mechanics and 99% of all the opinions I got back were that the alternator pulley was causing the noise. The latter 1% said turbo.

I had the alternator replaced and the howl didn't go away.

So I left the noise as it wasn't affecting the performance of the car. It was just a nuisance, like squeaking brakes. The noise never got worse, or louder, or longer, and nor did the car pull a Christine on itself and repair itself when I wasn't looking.

Today, it has changed for the worse.

The howl is louder, and longer, and doesn't go away for a long time, howling all the while I'm driving like a grandpa because the car is cold. It made its regular howl in the morning, and again at lunch time when I quickly popped out from work. Then, leaving work this afternoon I noticed it had gotten worse.

I know it's the turbo because I got home (it was still howling) and opened the bonnet and a friend held the revs in the "howl spot" whilst I listened around. The side of the engine without the turbo (where the alternator is) was not where the howl was coming from. The turbo is on the other side of the engine where I could clearly hear the noise was. There's nothing else that side that could possibly cause the noise. You can hear it's emanating from a spinning item. This howl started even before I got the software done on the car. Yes, it's been a while.

The car isn't loosing power.
It's not smoking any different. Smoke is black as usual.
No funny vibrations.
Nothing out of the ordinary.

Except for the howl...


There's a place in Honeydew that will replace the turbo with a brand new Garrett GT25, all inclusive: R14k

Then, there's a place in Springs that will replace with a recon Garrett GT25 for R7k.

Turbo Exchange and Turbo Direct both say they don't exchange that particular turbo, but can provide me with a new one, both at around R12.5k.


Any thoughts, gents? :chef:
 

Silverbird_96kw

///Member
:thumbdo:

Wish i could give you the correct answer, just don't understand why it will only do it when its cold, why not in every gear with a loud Howl...

But it could be turbo maybe a leak somewhere, but the car feels normal, I don't get it I give up.
 

netercol

New member
in my experience a turbo starts howling when it goes out of balance.. which can be caused by wear (usually comp wheel touching sides) or losing a tip on the turbine side (does not have to be a massive chip)

on the other hand turbo's can last quite a while howling like this, depending on how big the imbalance is, and how hard the turbo works..

just remember a recon unit wont have garrett parts in it. garrett dont make service parts for the vnt turbo's.
 

DieselFan

Honorary ///Member
Like i said you can use an early e60 530d turbo with minimal mods. If I were buying new I'd go that route.

Other than that you have my thoughts on this. And I'm pretty sure turbo exchange do have this turbo as they had it when I did mine. Or just let them recon the thing. It doesn't take long.
 

DieselFan

Honorary ///Member
Nope. YouTube gt2256v vs gt2260v . The guy did the swap on your car. It just shows the two turbos. It is the same turbo used on the 150kw e46 330d however the outlet is angled the same as the turbo you currently have making it a much easier mod. The turbo is however more expensive it is 16k on g drive. But it would be a nice upgrade. And the only mod you would have to make is to your one boost pipe. Anyway I'm sure you will make the decision which best suits you. But its the route I will probably be going eventually. That or an f30 330d turbo modified to a vacuum actuator.
 

Ralf*

///Member
gonna subscribe to this thread, no expert advice from my side

the only reason I can see for any form of "howl" is that the airflow isn't as smooth and laminar as it should be, causing a "reed-ing" (as in reed/wind instrument), and this can only happen of
1) some of the compressor blades or turbine blades are worn/distorted allowing air to flow or bypass areas where it would normally be contained and correctly and/or smoothly channeled
2) damaged blades ie chips/nicks causing disrupted airflow

I haven't heard the howl, so cannot comment on whether it is more a high speed friction sound, ie compressor or turbine blades in contact with the body, or centre bearing making the noise....or whether it is the disrupted airflow only causing the "howl".

if the noise is purely due to disrupted airflow, due to air bypassing the compressor by leaking around the edges, or by leaking around the turbine, then I woudn't be concerned for a catastrophic failure.

if the howling is due to distorted or chipped blades, then my personal concern would be for the chip or distortion to develop into a larger crack eventually causing the blades to catastophically throw themselves...the harder the turbo works w.r.t rotation speed, temp, and pressure, will accelerate the failure.

if the howling is actually a mechanical noise due to rubbing of the compressor or turbine against the housing, or due to the centre bearing, then catastrophic failure might be imminent as well.


alternativelly, before going for a drive, open hood, tell FIDO (Siberian Husky) to get out and into his own dog-house...close hood...problem solved

:rollsmile::rollsmile:
 

ChefDJ

///Member
DieselFan said:
Nope. YouTube gt2256v vs gt2260v . The guy did the swap on your car. It just shows the two turbos. It is the same turbo used on the 150kw e46 330d however the outlet is angled the same as the turbo you currently have making it a much easier mod. The turbo is however more expensive it is 16k on g drive. But it would be a nice upgrade. And the only mod you would have to make is to your one boost pipe. Anyway I'm sure you will make the decision which best suits you. But its the route I will probably be going eventually. That or an f30 330d turbo modified to a vacuum actuator.

The E39 has a GT25.
 

ChefDJ

///Member
I'm sort of leaning towards getting a new one fitted at the place in Honeydew called Alpine Turbo. Anybody had experience with them before?


Dhp507 said:
Speak to Stallion Turbos also...........

I thank you. Very much so.

Phoned them...

R5200 incl. VAT for a recon.

R8900 incl. VAT for a new one.

:slow:
 

Rayzor

Well-known member
ChefDJ said:
I'm sort of leaning towards getting a new one fitted at the place in Honeydew called Alpine Turbo. Anybody had experience with them before?


Dhp507 said:
Speak to Stallion Turbos also...........

I thank you. Very much so.

Phoned them...

R5200 incl. VAT for a recon.

R8900 incl. VAT for a new one.

:slow:



Thats pretty decent :praise:
 

ChefDJ

///Member
It is indeed. The guy says he bought 15 of them 3 years ago and has 2 left which he's battling to move. Says it's an original Garrett GT25 which he used to sell for 9900 ex vat.


How difficult is it to remove and replace a turbo on an E39?
 

Ralf*

///Member
just a quick though regarding the howl

thinking about my Jet Engine experience (previous trade and career), howling usually occurs when airflow is disrupted before it hits the front face of the compressor, ie withing the intake, the disrupted air impinging on the Jet compressor causes howling or droning

think of the Vulcan Howl (youtube this), caused only due to non-laminar flow of air within the intake as it reaches the compressor

so...if it were me....a quick inexpensive check, would be to investigate the air-intake area, to ensure that there are no blockages/restrictions/leaks in the main air intake pipe, thereby ensuring an undisrupted smooth arrival of air before it enters the compressor area of the Turbo
 

ChefDJ

///Member
Ralf@Speedway Motorsport said:
so...if it were me....a quick inexpensive check, would be to investigate the air-intake area, to ensure that there are no blockages/restrictions/leaks in the main air intake pipe, thereby ensuring an undisrupted smooth arrival of air before it enters the compressor area of the Turbo

Would this not cause permanent howling and not only howling when cold?


And definitely doesn't sound like a Vulcan howl.
 

anton-sa

Active member
ChefDJ said:
Ralf@Speedway Motorsport said:
so...if it were me....a quick inexpensive check, would be to investigate the air-intake area, to ensure that there are no blockages/restrictions/leaks in the main air intake pipe, thereby ensuring an undisrupted smooth arrival of air before it enters the compressor area of the Turbo

Would this not cause permanent howling and not only howling when cold?


And definitely doesn't sound like a Vulcan howl.



not necessarily, hot air and cold air have different densitys....
possibly different flow speeds? yes
 
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