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Replace Single Fan with Dual Fan

 
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dieselmartin
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Post08-08-2013, 20:23    Subject: Replace Single Fan with Dual Fan Quote

Hi.

Our BLS only has a single fan installed.
1K0 121 207 AS
1K0 121 205 AA
It's making a noisy racket because the fan is probably not properly balanced anymore.


Mechanically, the 1K0 121 207 T double fan should fit.
It was installed with AHK/automatic functions in the BLS.
Besides, you can find it at a good price on eBay right now.


Does anyone know if it can be easily replaced with an electric version?
Unplug the connector, remove four screws, and you're done?


m;
Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:25.
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Post14-08-2013, 16:42    Subject: Replace Single Fan with Dual Fan Quote

Let's compare the plugs here:

http://www.teilesuche24.de/hs/luefter-motorkuehlung-70455440?c=100337

with what you have on your car.
Sommer: A4 B5 Avant 2,5 TDI Quattro Facelift (AKN silber)

Wartet auf H Kennzeichen: A4 B5 Avant 1.9 TDI Quattro (AFN Schwarz)

Winter: A4 B5 Avant TDI Quattro (AFN rot)

Alltags Spardose: Audi A2 1.4 TDI (AMF Silber)


Translated on 27-09-2026, 18:26.
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dieselmartin
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Post14-08-2013, 19:54    Subject: Replace Single Fan with Dual Fan Quote

Yes.

It looks like the plug is the right type.

I believe it's more likely a difference in the fan motors/ECUs.
And for that, one would need to know the tuition fees of the programs being offered.
Most of the time, only the part numbers for the fan modules (which are actually always 1K0 121 207 T) are listed.



Golf_5_Luefterstecker.jpg
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 Replace Single Fan with Dual Fan
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Golf_5_Luefterstecker.jpg

Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:26.
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guste100
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Post15-08-2013, 10:59    Subject: Fan Upgrade: Single vs. Dual Fan Replacement Quote

dieselmartin wrote:
Does anyone know if it can be easily replaced with an electric one?

Hi Martin,
I don't know. But I would be very surprised if VW used different pin configurations or different protocols/commands for the fan. Therefore, I would suggest trying it out if you can get it cheaply.

Greetings.
Guste.


Translated on 27-09-2026, 18:27.
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dieselmartin
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Post15-08-2013, 11:56    Subject: Replace Single Fan with Dual Fan Quote

I once asked the auctioneer about the noise level of the fans.

Because VW uses different fans depending on the engine type.
I think I'm on the safe side with the low-waste heat BLS system.

Alternatively, I was thinking about removing the simple fan and trying to balance it. Perhaps I would then be able to see where a weight is missing.

If I can't easily remove it, I'll have to wait for the next crash icon_twisted.gif before I can get the front back into a serviceable condition.

Unfortunately, the Passat is getting louder with real problems (control arm bushings, xenon shutter), so the humming fan in the Golf is taking a bit of a backseat.

m;
Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:29.
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dieselmartin
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Post15-08-2013, 17:07    Subject: Replace Single Fan with Dual Fan Quote

SO.

The simple exhaust fan vents from the top, without requiring much modification.
- Intake located between the crossmember and the air filter housing.
- Removing LuFiKa makes it more pleasant.
- Remove the soundproofing underlayment so that the fan can be rotated far enough.

Apparently, he never used weights.

It seems like having the quiet dual fan is purely a matter of comfort.
Or, the simpler one has a hidden defect that isn't noticeable when turning it by hand.

m;
Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:30.
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dieselmartin
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Post15-08-2013, 21:33    Subject: Replace Single Fan with Dual Fan Quote

Here, you can hear the strong humming sound, which the fan also transmits as vibrations to the body of the car:



Replace Single Fan with Dual Fan - EinfachBrumm.flv
 Description:
 Brummender Kühlerlüfter Golf 5.
 File size:  5.04 MB
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Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:31.
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T3Surfer
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Post15-08-2013, 21:52    Subject: Replace Single Fan with Dual Fan Quote

Does the propeller show any imprint or rust marks from a potentially corroded counterweight? If so, this indicates imbalance, which causes vibrations. The higher the speed, the more intense the vibrations will be.
NA,Gehörlose wie ich können auch Schrauben! Ihr HÖRT ich FÜHLE! T3 TD EX-JX Jetzt 1Z mit 122PS und Renaultgetriebe Golf II TD Bj 84 512Tkm Passi 35I 1Z 468Tkm--> Seat Toledo AHF-- Toledo ARL 477Tkm mit Spritspartuning icon_wink.gif 99er T4 Syncro-Cross 100800km grad eingefahren


Translated on 27-09-2026, 18:32.
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Post15-08-2013, 22:02    Subject: Replace Single Fan with Dual Fan Quote

It sounds almost like a faulty alternator bearing. Are you sure the bearing is still in good condition?
Even at half speed, it sounds incredibly loud.
LG, Onkel BM

*Nichts ist einfacher, als sich schwierig auszudrücken......*

**Technische Fragen bitte ins Forum und nicht in mein Postfach**


Translated on 27-09-2026, 18:32.
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dieselmartin
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Post15-08-2013, 22:11    Subject: Replace Single Fan with Dual Fan Quote

I thoroughly inspected the entire propeller and cleaned it.
Not a trace of a lost counterweight.

When you turn it manually, you can hear a slight humming sound.
The bearing is otherwise completely free of any snags or play, so it is not fixed or seized in any areas.

That's what surprises me the most.
Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:33.
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T3Surfer
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Post15-08-2013, 22:29    Subject: Replace Single Fan with Dual Fan Quote

Perhaps the propeller is rubbing against the housing under load.
NA,Gehörlose wie ich können auch Schrauben! Ihr HÖRT ich FÜHLE! T3 TD EX-JX Jetzt 1Z mit 122PS und Renaultgetriebe Golf II TD Bj 84 512Tkm Passi 35I 1Z 468Tkm--> Seat Toledo AHF-- Toledo ARL 477Tkm mit Spritspartuning icon_wink.gif 99er T4 Syncro-Cross 100800km grad eingefahren


Translated on 27-09-2026, 18:33.
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dieselmartin
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Post16-08-2013, 10:09    Subject: Replace Single Fan with Dual Fan Quote

T3Surfer wrote:
Perhaps the propeller is rubbing against the housing under load?


I cannot absolutely rule that out, because I wasn't directly involved, icon_wink.gif
"However, since it moves a significant amount of air, it will at most be pulled away from the casing (as you can see in the video, it even moves forward)."

And there are no signs of grinding on the radiator.



Golf_Kühler.JPG
 Description:
 Kühler Golf 5
 File size:  160.8 KB
 Viewed:  1609 times

Golf_Kühler.JPG

Transparency, Teamwork
... there was another T.

I don't know what the f*ck it was.


Translated on 27-09-2026, 18:34.
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T3Surfer
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Post16-08-2013, 19:16    Subject: Replace Single Fan with Dual Fan Quote

Too bad I can't "feel" the video, but don't stop listening!
Perhaps a slight bearing defect that only becomes "audible" at high speeds; does the noise change when you move it back and forth? Similar to how a developing wheel bearing issue might sound when you steer left and right at around 60-110 km/h?
NA,Gehörlose wie ich können auch Schrauben! Ihr HÖRT ich FÜHLE! T3 TD EX-JX Jetzt 1Z mit 122PS und Renaultgetriebe Golf II TD Bj 84 512Tkm Passi 35I 1Z 468Tkm--> Seat Toledo AHF-- Toledo ARL 477Tkm mit Spritspartuning icon_wink.gif 99er T4 Syncro-Cross 100800km grad eingefahren


Translated on 27-09-2026, 18:35.
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Post18-08-2013, 14:53    Subject: Replace Single Fan with Dual Fan Quote

Hello Dieselmartin,

I also had problems with the fan in my Audi. Initially, the bearing made noises, similar to a faulty alternator clutch.
After about 3 weeks, the fan was completely broken.
Chips from the storage area have gotten into the winding.
At the icon_biggrin.gif, we had never had a fan that was defective.
New fan installed, and it's been quiet ever since.

SG.


Translated on 27-09-2026, 18:36.
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