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Old 05-01-2001, 08:02 PM
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We have a 1985 300D Sedan with just over 105,000 miles. This car was passed down from my great uncle who had ties with Mercedes. I have this reoccurring problem with the car. Ever since we can remember, there is a whistle just before the turbo kicks in. In the last year it feels like the car is loosing power. On anything over a minor hill, the car will start to whistle as if almost to engage the turbo charger. Right then the car looses power and slows down. If you push harder on the pedal, the car will go from third into second. Our local Mercedes Benz dealer has not been able to fix this problem. Also the car shifts hard between gears.
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Old 05-01-2001, 08:12 PM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,877
Are all the hoses

connected and secure under the hood? Also, I would check the "banjo" fitting at the back of the intake manifold to insure that it is clean/clear and you are getting a good signal to the aneroid valve on the fuel injector.
'85 300D
'95 E320
'97 CRV
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Old 05-04-2001, 01:53 AM
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Join Date: Jun 2000
Location: Near Williamsburg, Virginia
Posts: 359
If you've got a whitsle you got a leak. Hard shifting is common with the 123 and easy to adjust so it is smooth. To start with make sure you have clean fluid, and a good filter. It must be changed every 30,000 miles. Then have someone who knows, adjust the transmission.
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Old 05-04-2001, 06:04 PM
ML Dude's Avatar
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Join Date: Mar 2001
Location: Southern California
Posts: 373
Hey there,

I've got the same car and similar mileage, also passed down from the family!
You don't mention how long you've actually been the driver of the car so maybe this is a moot point. But if you are new to the car let me tell you something about it's turbocharger.
I've owned three cars with turbo's and the 300D's behaves unlike the other two. First of all, a whine(whistle) is not unusual for a turbo, if the sound is loud, it's likely you have some failure in the insulation rubber grommets in the firewall. These are there to pass through wiring and such and maybe one or more a simply dislodged or are worn. This would allow the normal turbo whine to enter the cabin more loudly than desired.
The turbo will kick in at approx. 3K rpm and more quickly under load conditions. To find out if the operation is normal, I suggest the following simple test. Find an open stretch of road, put the tranny in position 2 vs. D, and drive at an engine speed of about 2500rpm. Now accelerate gradually and you should feel the turbo kick in at about 3K.

The other symptom you mention about the whine and loss of power I believe is due to what I said about behavior. "Normal" turbo operation the sound would increase as exhaust pressure rose, such as under load or acceleration. The MB turbo, the whine becomes apparent after the load is reduced and the turbo is slowing down! Struck me as odd, but, I've gotten used to it.

If your car passes the 2nd gear test, I wouldn't worry about it and just get used to the driving charc. of these diesels.

Good Motoring....!
Ed "Don't Benz's just feel better..."

Current wives...
2000 ML430 Skyview "The Mel"
2000 CLK430 Cab "The Cab"
85 300D Turbo "The Diesel"

Past wives...
92 300E
85 190E

"One should as a rule respect public opinion in so far as is necessary to
avoid starvation and to keep out of prison, but anything that goes beyond
this is voluntary submission to an unnecessary tyranny, and is likely to
interfere with happiness in all kinds of ways."
Bertrand Russell
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Old 05-04-2001, 10:49 PM
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Join Date: Jun 1999
Location: Los Angeles, Calif, USA
Posts: 521
If you think the turbo is not kicking in, check the ALDA (aneroid valve)hose and the banjo fitting as suggested by Jim. Search this forum for more info. Here is the basic info before searching. The turbo starts creating pressure in the intake manifold, the pressure is transmitted via a small hose to the ALDA which is on top of the FI pump. The FI pump will delivery more fuel as the pressure getting higher, and you will feel more power coming out of the engine. However, there is a overboot protection device (electric/pressure control valve) along the small hose to cut off the pressure to the ALDA if the pressure is getting too high. The protection device is activated by an electrical pressure switch on top of the intake manifold. If any one of the parts is not working correctly, you do not get more fuel to the engine when you need it. Problems can be clogged hose/fitting (very common), bad switch, or bad electric/pressure control valve. Of course, the turbo has a device called wastgate (attached to the turbo) which can be a problem too causing poor performance.

Yours is 1983 model and the turbo should kick in early, possibly around 1400 or 1500 rpm. The 1984 and 1985 model has smog device which will delay the turbo kick-in, possibly 2500 rpm.

The car shifts hard. The problem can be no vacuum getting to the tranny (caused by as simple as disconnected hoses or a missing cap on the vacuum module) or the vacuum module needs adjustment. Search this forum for more info.

I hope that helps.

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Old 05-06-2001, 07:03 PM
Registered User
Join Date: Jan 2001
Posts: 39

For what it's worth I had the same symptoms when I forgot to tighten down the clamp between the turbo and the intake. The small gap between the two pieces of plastic tubing caused a sharp jolt on shifts and that whistling noise.

1983 300D Turbo
1995 E320 Wagon
2001 MR2 Spyder
2001 Subura WRX Sedan
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Old 05-06-2001, 07:28 PM
Registered User
Join Date: Feb 2000
Location: Germantown, MD
Posts: 106
My Whistle...

I have an 85 300 TDT with 275k. At one point last year it developed a very obvious whistle at low rpm (~1500). The problem was due to a crack in the exhaust pipe exiting the is designed to flex but after a while it finally developed a could hear the turbo as if it were a jet engine winding up.

More food for thought.

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Old 05-06-2001, 07:55 PM
Posts: n/a
My '85 300D with 92k miles also has a pronounced whistle right before the turbo kicks in. I do not lose power at any point when going up hills, though, and we have a lot of hills in my area I would describe the shifting on my car as "hard" only on the 1-2 shift, and I have heard that's just the nature of the beast.
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Old 05-06-2001, 10:13 PM
David C Klasse's Avatar
CheFrac is Back!
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352

I found this website and thought it might help.
2006 E350 w/ 155k miles (Daily Driver)

1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)
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Old 05-07-2001, 08:38 PM
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Join Date: Jan 2001
Posts: 39
Something is not quite right

Straut - that hard shift 1-2 is not normal. When I corrected my reassembly error my shifting went back to smooth as glass. In fact I can't tell when the car shifts after it warms up. I bet you have a gremlin that can be fixed. After I fixed the problem I was confused - how would an air intake leak cause a tranny problem? So I loosened the air intake and drove around the block - the problem came back.

I think that with less turbo back pressure the engine spools up too much between shifts and makes it jerky. When the leak is fixed the engine takes long to rev up and that matches the transmission setup better.

BTW I didn't notice any loss of power.

1983 300D Turbo
1995 E320 Wagon
2001 MR2 Spyder
2001 Subura WRX Sedan
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