Hi, i just recently purchased an '85 300TD with 160,000 miles. I have been working on it and getting it ready to be driven daily. It has been sitting a lot and when i start it (about every other day) and it has been running for 2-3 seconds on its own power, there is a terrible grinding noise that lasts for about 1 second. It is coming from the general area of the turbo and i was wondering if this was caused from the oil draining out of the turbo and the oil bearing or something worse?

starter dragging is my guess. doesnt sound like what a turbo would do. is it brash and clear noises? if it were turbo it would be muffled i think.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If it happens while cranking or in the place of cranking your bendix is bad on the starter. You'll want to look into either rebuilding your turbo (recommended over a Bosch rebuild personally) or buy a Bosch rebuild.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Sounds like the starter isn't retracting fully. The only time a turbo would make that noise is if there is something large stuck in the vanes and it would make noise all the time.

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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

It is after the starter has diengaged as far as i can tell. Ill try to spell out the sound phonetically.

engine starts.grn..grn..grn..grn..grn..errrrrrrrrrrrrrrrrrrrrrrchrr..grn..grn..grn

Timeline...engine starts and idles for approx 1/2 second
grinding sound lasts for 1 seconds and fades away
engine resumes normal operation.
Also, no grinding or other sounds during starter motor engagement, only after engine is under own power

Also, turbo makes boost and the car is lively to drive. i think that the oil is draining out of the bearing and the sound is the shaft rubbing until oil fills the cavity and the shaft rides on the oil.

should be trapped on the bearings and maintain a film that provides protection on startup same as the engine bearings. you sure your oil is ok?

still sounds like some kind of starter bendix malfunction to me.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If you think it may be the turbo rubbing...the only place it would rub (and make such a noise without being a total failure) would be on the housing.
If you want to do a simple check (even though I think the starter may be the cuplrit), remove that big "U" tube off of the air cleaner where it hooks to the turbo..

Grab the shaft (WHILE THE ENGINE IS OFF) and move it side to side. If it hits anywhere on the housing...or you see indications of rubbing...you may have problems.
ALso push/pull the shaft to see if you have too much end play..

I still think you may be looking into a starter bendix...but its a good thing to check on the turbo anyway

My dad's '83 does the exact same thing when its colder out on occassion....essentially never when its warm though. Its got to be the starter just not disengaging.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

If I remember correctly, your car is capable of being push started. If so, push start the car, or roll it down a hill, until it starts on its own. This procedure takes the starter out of the picture.

If the grinding noise is gone, that it is the starter. If the noise is still there than, the starter is not the culprit.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]