I’ll post back when I get into it. Got it home and haven’t had the time yet.

Welcome to the mad house ! .

I'm betting the whirring sound it the starter spinning with the bendix retracted, this would account for why it needs jump starting....

Take the starter off and apart, clean it and lubricate it, paying special attention to the solenoid ~ I always replace the BOSCH solenoid as they tend to age out regardless of use .

Only use BOSCH or ECHLIN (NAPA) branded solenoids ! .

Cleaning it the first job, the low pressure SLS hose from the pump to the plastic reservoir is easy to replace and makes a HUGE mess when it gets old and weepy .
.

The SLS system requires special fluid, do not use ATF .

I'd remove the reservoir and clean it ASAP, there's likely to be sludge in the bottom of it you don't want circulating .

There's a filter in there you'll need to replace too, I find that several times of filling, driving then changing the SLS fluid will get all the old brown or black fluid flushed out of the system easily .

Have fun with this ! .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

My initial thoughts too. Who knows what's been done to this by prior owner(s) who all claimed they knew what was going on and how to fix it....

Steve

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Steve A
92 W140 OM603
97 VW Jetta TDI
90 Passat variant TDI 6 speed MT
94 Chevy K1500 6.5TD
05 E320 CDI
+ others

Please explain what the Bendix is please

The Mercedes Starter strictly speaking is not wholly a Bendix type starter however some people call the Starter gear a Bendix.

On the typical AC Delco Starter at least the ones in the old days the Solenoid activates a yoke that pushes the Starter Gear Forward and the Starter Gear is combined with what is called an overrunning clutch. With the over running clutch the gear is supposed to be able to engage the Ring Gear on the Flywheel and only turn in one direction. The Mercedes Starter has that.

The Mercedes Starter also have a Bendix arrangement that is a steeply threaded shaft. If for some reason the Gear manages to turn opposite (this would happen if the Engine started and was turning faster then the Starter Motor) of what it is supposed to the Bendix allows the gear to rotate on the threads and pull away from the Flywheel even if the Solenoid has the Starter Gear pushed forward.

On a bendix only starter there is a weak spring that retracts the Starter Gear
and when the Starter starts truing the the steeply threaded shaft spins pushes the Starter gear forward into engagement. The Starter Gear retracts after you stop giving the starter motor electricity and or the engine starts and spins the starter gear which will retract due to the steeply threaded shaft.

If you know what an actual bendix type starter (many air air starters are bendix type starters) calling part of other types of Starters a bendix is confusing.

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84 300D, 82 Volvo 244Gl Diesel

I'm a retired Journeyman Mechanic with over 50 years on the job and I still don't always know what I'm doing..... .

Learning by doing is a great way to learn .

When you work on older machines 90 % of the time you're correcting other's errors along with correcting the actual problem .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

My 77 has had the temp control set in the middle since I got it. One day I changed the setting and when reversing the starter kicked in after a 40 Mile drive. WTF, and when turning off the key nothing happened. WTF!! Put the setting back to where it was, car shut off normally.
Come back from work, the glow plug fuse was toast, and a new one (I keep spares in the car) did not do the job. Pull out and install the spare glow plug relay, jump start, and all has been good.
The PO had the dash out and did things like put led lights in and disconnected the AC and installed an 81 240d control panel so I'm thinking something in the hvac circuitry has been mis-wired.

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95 E300D gave away
77 300D, 227k, station car
83 300CD 370k, body gone away to the rust gods, engine is in a Yota pickup, going strong
89 190E 2.6- 335k, no more
79 VW FI Bus- 154k summer driver
59 VW Beetle ragtop- 175k
12 VW Jetta- 250k
74 MG Midget-78k

FWIW I'm pretty sure I mentioned the starter could be causing the whirring sound 7 or 8 days ago..............

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2012 Mercedes ML350 Bluetec 102K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 238K (mine)
1998 Volvo S70 T5 Turbo 211K (kids)
1994 Ford F150 4WD 246K (firewood hauler)
1983 Mercedes 300D 384K (diesel commuter)

I’m sitting here chuckling while reading the last post about the starter and relay issue.
Sure enough…there’s some kind of bleepy lighted switch sticking out of the dash. Not sure what it does. Part of a previous alarm system?
We’ll see. Adventures await.

It’s the cooling fan at the front of the radiator!
Although it sounded like the grinding of all grinding…I left it on and ran around the front of the car. Sure enough…cooling fan.

When I say loud, I mean like serious db’s

It could be a faulty a/c temp switch at the receiver/drier. I don't remember if 617 cars have the overheat sensor to trigger the fan but if they do then that could also be the cause. Disconnect it and see if it makes a difference. There will be 2 sensors at the drier: one for the fan and one for the too low/too high pressure

There's a video on youtube of a guy who takes his apart and replaces the bearing. He's actually a poster on this forum.

Think I saw this a couple weeks ago?

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1981 240D 4sp manual. Ivory White.

aux fan rebuild (good stuff)
https://www.youtube.com/watch?v=NlI09Suc0SM

Maybe I'll try that next time .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better