Why does my turbo wistle in my 85 300d but not in my 83 300d
 

Ive been driving my benz's lately and ive been noticing that i can hear the turbo in my 85 300d but not in my 83 300d? Whats the deal with turbo? clean it?

It might be the air recirculting valve not the turbo. The 85 should have one, but the 83 wont.

My 85 300TD whistled until I put a BB in the vacuum line going to the ARV.

Ah Ha!

(sorry to dig up an old post...)

I have exactly the same problem... my new (to me) '85 300TD makes a noticeable whistling/wheezing sound between 2000 and 2500 RPM. My '83 sedan is quiet as can be. I found another post on how to disable it and we'll see tomorrow if that fixes things.

all the 617 turbos used in the 85's use an air recirculation scheme and it results in a wheezing noise. Thats one difference between the 85 and previous models, bedsides the differential gearing and the electronics for the Tach
I always thought the blue flying saucer thing also results in smoother shifts.

My wagon has no noticeable wheeze......

My '85 300D had the same noise/whistle. After numerous questions and posts, I dropped a BB (by the way, BBs are 4MM. The same size the service manual says to use to block vacuum lines for testing purposes) into the vacuum line to the ARV and the EGR, as well. Presto! No more annoying squeal/whistle! I recommend this to all.
While I'm posting, I'd like to thank everyone on this forum for all of their help and knowledge. I have learned so much about my car just by reading so many posts on this site. Merry Christmas to all of you!

my 85 doesn't whistle one bit. My 84 though, whistled like hell! I loved that car, and I miss that whistle. I read somewhere recently that the whistling is commonly cuased by a bad rubber seal between the turbocharger and that U boot that connects the turbo and air cleaner. it goes bad, leaking unfiltered air into your engine and letting the whistle out. I recently checked that seal on my 84 and its hard as plastic. Ill definetly replace that before I put that engine back into service.

The '83 may not know the tune.....

Tom W

It may not know the "words"......;)

No, Jimmy, you say it may not know the words when it DOES whistle. When it does not whistle it doesn't know the tune!:P

Tom W

Is this a turbo wheeze or a transmission wheeze? I think there is a vacuum vent (or intake?) inside the car... placed there for 'cleaner air'.

My 85 has the whistle. My 79 SD does not. At least now I have an idea why.

In our SD, there is and has been a slight whistle since we acquired it. The turbo spins freely.

In our TD the turbo DID NOT spin freely and there was no whistle. I rebuilt that turbo which now spins freely and it whistles. My "opinion" is that the speed of spooling and RPM of assembly will impact the sound. This assumes it is balanced which if off (I am told) also produce a whistle. Again, this is my opinion and it is based on my experience.

That was my problem... I used Brian Carlton's 9 step guide to EGR/ARV freedom yesterday -- Today my car was as quiet as can be. And, I don't feel the turbo kick in at ~2500 RPM when the ARV closed. The power is smooth and constant all the way up.

Much better!

Thanks to everyone here! It's been about 1.5 years since I got my first diesel Mercedes and I wouldn't have gotten very far without all the information here! Thanks again and happy holidays!!!

Greta whistles "Dixie"-no wait, that's me-out my a$$.

DS