Hey everyone,

So my w123 is making a strange noise on cold starts.

It's a loud whirring noise, almost a hollow whistling, if that make any sense?

I'm wondering if it's a fan clutch?

There are no mechanical symptoms, just the noise.

But it is concerning.

I'm getting ready for a 12hr round trip and I was planning on taking the w123 but now I'm a little worried.

Any ideas?

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'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking

Vacuum pump?

Sixto
87 300D

Cruise control actuator? Mine randomly comes on sometimes and makes a noise similar to what's described in the OP.

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83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
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88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

Cruise control has been removed, maybe the vac pump?

The car has been slow on shutting off after I turn the key....

__________________


'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking

I'd definitely rule out that vacuum pump first as suggested by sixto.

Could even be a leaky vacuum connector, hose or vacuum fuel cutoff as you mention it's slow to shutoff.

Divide and conquer! MightyVac time.

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1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

Starter bendix failure...

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Technically speaking, there is no Bendix in the W123 starters. Bendix type starters were phased out in the 60's. The Bosch starter is an over-running clutch type with a solenoid and a lever to engage a pinion gear on a one way clutch, which drives the ring gear. The solenoid also operate a high current contactor which supply juice to the starter motor.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
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Could it be your tach magnetic pickup hitting the pin on the harmonic balancer?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

This can be dangerous for your teeth! But sometimes gripping one end of a screwdriver in your mouth and placing the other end against a bit of the engine that isn't moving but close to where you think the whirring is coming from can help. Be careful.


And I'll say it again be careful.

but the whirring could give itself away in the form of vibration that will transmit through your skull to your ears and will sound louder than before.

Don't do this for too long - you could not only damage your teeth but your hearing.


(This is a cheap mechanic's stethoscope)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

The problem is the car doesn't make the noise idling or if I rev the engine idling,

It really only starts when the car is moving.

There are some messed up connections in the vac lines that I will photograph and post.

It's not related to the new tachometer because it's been making the noise for a long time.

I'll post photos in a few.

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'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking

Ah ha when it is moving... do you get a change in whirring with the clutch depressed?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

No change clutch in or out.

__________________


'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking

Are you thinking pilot bearing, Army?

Sixto
87 300D

Open connections in Vac system.

On the first picture there is a completely open connection, not sure if this is a problem or not?

On the first picture I'm holding a woven hose, and it's all cracked around the base so that is certainly not airtight.

On the second picture, you can see where the woven hose connects on the otherside of the engine, again, it's cracked around the base so it's not an airtight connection.

Not sure if either of these would have ANYTHING to do with the whirring noise.

Attached Thumbnails

   

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'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking

btw, the second picture is just above the alternator and has a hose connected to the radiator, i'm not sure what it's called.

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'85 Euro 300D - 258k 4 spd manual
'85 300TD Wagon - 180k - SOLD
Always looking