for the past few months i have been trying to find the source of an annotingly loud whistle at freeway speeds, was definately engine speed specific, meaning it would occur at very specific rpm, i could hear it really loud with the sunroof open and passing under a bridge, well i had originally suspected the turbo, mine was fine, but i had a spare, so i changed it out, noise was still there, then i moved to the vacuum pump. was going to change that out on sat, but since i recently changed to 99.9% bio diesel. i wanted to see how bad it smoked during a cold start, so i had my friend start my car, when he did, he accellerated the engine, and the whistle was coming from the exhaust!!to i banged it with a hammer trying to dislodge what ever it was, but was not able, today i installed a new muffler and all is now ok. anyone need a good air research turbo??

1979 300SD 116.020

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1967 250 S
1967 280SE
1968 250S
1971 280 SE
1973 220
1974 280 S
1975 450 SEL
1976 220 D
1979 300SD
1983 300 SD
1985 230 TE euro
1986 280SL
1986 500 SEL euro
1986 190E 2.3
1990 300 SE
2003 C230 K
2004 C230 K
1987 560SEL
1987 300SDL now in canada
2005 C230
1998 C43 AMG Sold to DON
1993 190E 2.6
300TD Former daily driver Totaled
current:
R320 CDI
Ram 2500 Cummins

Check your manifold bolts. I recently had the same problem and I was getting ready to replace the gasket. All of the bolts where totally loose and the gasket was fine! It's not uncommon for those to loosen up with all the expansion and contraction of the metal goin on there.

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"spreading a trail of obnoxious where ever we go"
1981 300sd w/ 341,500 miles

http://www.wecrash.com/pics/ddda_banner.gif

I had the same thing on my 1975 240D. Turned out to be pinholes in the exhaust near the muffler. New exhaust, no more ear piercing, nearly pure, high-ptched tone at certain speeds and throttle positions.

Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

those were recently retorqued, definately at the rear muffler, very audible when you are standing next to it, since i hit it with the mallet, it is much worse and more frequent

__________________
1967 250 S
1967 280SE
1968 250S
1971 280 SE
1973 220
1974 280 S
1975 450 SEL
1976 220 D
1979 300SD
1983 300 SD
1985 230 TE euro
1986 280SL
1986 500 SEL euro
1986 190E 2.3
1990 300 SE
2003 C230 K
2004 C230 K
1987 560SEL
1987 300SDL now in canada
2005 C230
1998 C43 AMG Sold to DON
1993 190E 2.6
300TD Former daily driver Totaled
current:
R320 CDI
Ram 2500 Cummins

replaced the rear muffler and all is well, nose is definately gone now

__________________
1967 250 S
1967 280SE
1968 250S
1971 280 SE
1973 220
1974 280 S
1975 450 SEL
1976 220 D
1979 300SD
1983 300 SD
1985 230 TE euro
1986 280SL
1986 500 SEL euro
1986 190E 2.3
1990 300 SE
2003 C230 K
2004 C230 K
1987 560SEL
1987 300SDL now in canada
2005 C230
1998 C43 AMG Sold to DON
1993 190E 2.6
300TD Former daily driver Totaled
current:
R320 CDI
Ram 2500 Cummins

I have that happening with my car too. Does it sound like its coming from the engine bay? Mine does.

it did sound engine related, i replaced the vacuum pump and the turbo, fortunately i had spares, have someone rev the engine while you listen at the exhaust

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1967 250 S
1967 280SE
1968 250S
1971 280 SE
1973 220
1974 280 S
1975 450 SEL
1976 220 D
1979 300SD
1983 300 SD
1985 230 TE euro
1986 280SL
1986 500 SEL euro
1986 190E 2.3
1990 300 SE
2003 C230 K
2004 C230 K
1987 560SEL
1987 300SDL now in canada
2005 C230
1998 C43 AMG Sold to DON
1993 190E 2.6
300TD Former daily driver Totaled
current:
R320 CDI
Ram 2500 Cummins

Check your exhaust manifold flanges and gaskets. A nut vibrated itself off of one of the studs on the flange connecting the manifold to the turbo, and a leak formed. When the engine was under a good load, it sounded like I was strangling a rat under the hood. Probably a combination of the turbine whine and the gasket acting like a reed . I was losing a bit of boost pressure too, so if you're performance is down as well, I'd definitely take a look.

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Dale

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1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel