I have replaced pretty much all of the vacuum rubber hose connectors at the overboost switch, alda and the blue vacuum pod, some hoses had huge holes in them. The car is still whistling at 1500-2000 rpm and I cant really pinpoint where the sound is coming from! Are there any other hidden vacuum connectors that I should know about?
1987 300D

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1987 300D
2005 E320 CDI

A vacuum leak wouldn't whistle. Are you sure it's not a door seal? My turbo is slightly noticeable at that rpm.

Don't worry, it will only be serious when it starts to sound like this....

YouTube





Is it a high or low pitch whistle?

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1982 300GD Carmine Red (DB3535) Cabriolet Parting Out
1990 300SEL Smoke Silver (Parting out)
1991 350SDL Blackberry Metallic (481)

"The thing is Bob, its not that I'm lazy...its that I just don't care."

Generic instructions for finding a leak where there is some sort of gas or Air pressure leaking out.

Where My Wife Teaches Pre-school they use this to make Bubble Mix. One gallon of Water to one cup of Dawn Dish Soap.
Reduce the amounts as you see fit.
Put the Mix in a Spray Bottle and Spray it on the Cold Engine and Exhaust Manifolds and Intake Manifolds; as well as the Turbocharger.
Start the Car up and before it gets hot rev up the Engine and see if there is any Bubbles.
If there is Bubbles you have located a leak.


Another thing that can make that that whistling sound is if one of your Turbocharger Wheels is rubbing the housing.
Unfortunately you have to do this to both ends of the Turbo.
Push the Compressor Wheel inwards towards the Bearing Housing and rotate it all the way around and see if you can hear any scraping (may need a Stethoscope or something similar).
Do the Same on the Exhaust Turbine; push it towards the Bearing Housing while rotating it and listen for rubbing.
Sometime you can see on the fins where it has rubbed. That shows up most often on the Compressor Wheel.

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84 300D, 82 Volvo 244Gl Diesel

X2. Check the fittings between the turbo and the intake manifold including the mixing pipe and EGR valve. Temporarily cap the ALDA signal line at the manifold to see if that's where it's leaking.

X2 also what Diesel911 said but rotating the turbo shaft from the compressor end should tell you what's going on at the turbine end. It's a day's work to remove the downpipe and the section of cast pipe downstream of the wastegate housing. It might be less work to remove the turbo.

Sixto
87 300D^2

Just had someone rev the engine while I was at the engine bay listening, the odd thing is that I can hear no whistling sound while standing still. Only while moving and coming up on 2000 RPM, after the rpm has been reached the whistling goes away. Also no sounds at the lower rpm.

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1987 300D
2005 E320 CDI

The turbo is hardly blowing without a load on the engine so your test points an additional finger at the turbo and intake system, and removes one from the vacuum system.

Sixto
87 300D^2

It's not going to spool up at idle, the engine needs to have a load on it for the turbo to really spool at all. I think this is what sixto is getting at as well but I found it a bit hard to follow.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

It's hard to understand me with BLACKCDI's turbo whistling in the background

Sixto
87 300D^2

pffft! I'd be worried if it sounded like THIS!

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I will start looking at the intake manifold and turbo, thanks guys. Can the turbo really be going out, it pulls like a freight train after 2500 rpm...Its a garret unit.

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1987 300D
2005 E320 CDI

Who said anything about the turbo going out? I'm talking about an air leak.

Sixto
87 300D^2

Diesel911 suggested one of the turbocharger wheels might be rubbing the housing. Hope not, will check it out

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1987 300D
2005 E320 CDI

Comment on the Turbo Charger.
The Exhaust Gas pressure pushes the Trubine Wheel away from the Turbie housing and towards the Bearing Housing meaing that it is also pushing the Compressore wheel towards the Compressor Housing. So it is more normal when a Wheel makes contact with the Housing for it to be the Compressor Wheel that is rubbing. I rubs due to wear on the Thrust Washer and or the Thrust Bearing.
For the Turbine Wheel to rub on the Housing there most often has to be worn Shaft Bearings; the Compressor Wheel can also rub for the same reason.

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84 300D, 82 Volvo 244Gl Diesel