Electric Fan Conversion - Stern Garage - SPAL Fan

[Jlaa]

Moderator update: The Stern Garage "shop" links from their main website appear to be broken as of April 2025.

I saw this mentioned in passing some time ago and today I realized that SG now has this on their website:

W124 M119 Elektrolüfter Umbausatz für 400E, E420, E500, 500E, E60

Hiermit bieten wir Ihnen einen Umbausatz von Visco- auf Elektrolüfter an. Ideal für Modelle mit M119 Motor, die thermisch hoch belastet sind, wie W124 400E, E420, E500, 500E, E60. Hochwertige Aluminium Lüfterzarge in neuem Design mit einem extrem starken Spal-Lüfter. Der Umbausatz umfasst alle...

stern-garage-shop.com

It is EUR683.81, which doesn't seem unreasonable if put within the context of the price of an OE visco fan clutch.

EDIT - I cannot seem to find their email address though. It would be great if we could see the instruction manual, and if we could see if this requires a new alternator.

 

[gsxr]

There's a lot of unknowns. What is the CFM for the electric, vs CFM of the mechanical fan fully engaged? What is the SPL noise level of the electric? I assume it's fixed speed, not variable speed, and obnoxiously loud like most electrics (think the factory twins on high speed - I hate them).

The OE variable-speed fans used on the W211 and other later cars are quiet and large enough to pull massive amounts of air. I'd be far more interested in a conversion that kept the OE setup (variable speed, quiet, adequate CFM) vs aftermarket, loud, and probably reduced CFM... but that's just me.

Note that the main reason to get one of these is to make room for your supercharger drive pulley...

 

[Jlaa]

There's a lot of unknowns. What is the CFM for the electric, vs CFM of the mechanical fan fully engaged? What is the SPL noise level of the electric? I assume it's fixed speed, not variable speed, and obnoxiously loud like most electrics (think the factory twins on high speed - I hate them).

Good point. I will ask. For what it is worth, I also hate all the noise that the OE electric fans make on high.

 

[JC220]

I agree with Dave here that a fixed speed aftermarket fan cannot push even close to the CFMs the mechanical fan does!

Indeed I did make a proper aluminium dual electric fan setup for my 500E and despite using powerful fans and a temperature controller it did not work.

Best keep the viscous fan and forget about throwing money after bad on these IMO. Been there done that!

The only proper electric solution for an older MB is if someone was able to retrofit and control a modern higg powered fit for purpose MB PWM controlled electric fan.

 

[alabbasi]

Maybe it would be better to take a fan from an E55 or S55. Those should be up to the task.

 

[500AMM]

Just for reference on the topic:

E500E Electric Fan conversion thread | M119 Engine

This is a follow-up of a thread in the W126 section we hijacked. Basically its about getting rid of the mechanical fan clutch and replace it with an electrical fan setup. All infos, Ideas and whatever are welcome here. So far, Jelmer and me would like to be the first 2 guys that do such a...

www.500eboard.co

I don't recall if this setup has a variable fan speed. IIRC anyone else but @Jelmer and @Christian_K installed this on their cars. I think the new owner of Jelmers car took it off, but Christian may still run with it.

Here is an updated link to Flex-A-Lite:

Flex-A-Lite® Automotive Home page

Performance cooling products for the automotive market. Flex-a-lite invented the Flex Fan and holds the patent for the first electric fan for the automotive aftermarket. The full product line now includes the patented Flex-a-fit aluminum radiators, electric fans, belt-driven fans, oil coolers...

flex-a-lite.com

They have an adjustable speed controller, which doesn't mean it operates in variable speed mode. I haven't read the specs BTW.

 

[JC220]

The difference is that lets say when MB went to electronic engine cooling fan on a W211.

This is a very high powered electric fan possibly needing an alternator upgrade and heavy wiring feed.

Crucially, it is variable speed and controlled by the Engine ECU. I'm sure this monitors a variety of factors and it does speed up the fan gradually to control the engine temperature steadily.

These MB factory fitted electric fans also push ALOT of air - small aftermarket offerings would not compare at all.

And whereas where some aftermarket fans may have "variable adjustment" this still only relates to a sensor fitted which turns the fan on at a set / adjustable temperature point. On off control only. Which means that where the w211 MB fan is quiet in almost all conditions and maintains a perfect engine temperature, aftermarket electric fans on a w124 will only come on and roar when they are called for an off again. The result being a unhappy cooling system potentially as it is now also experiencing spikes in engine temperature by design of aftermarket control strategy.

 

[500AMM]

As for Stern Garage, here is another part they are making:

Lochkreisadapter für die Kardanwelle W201, W202, W203, W124, W210, C20

Hiermit bieten wir Ihnen spezielle Lochkreisadapter für den Antriebsstrang verschiedener Mercedes Modelle an. Wer sich schon einmal mit dem Umbau auf ein anderes Getriebe oder Differential z.B. im Rahmen eines Motor-Swaps oder Umbaus von Automatik auf manuelles Getriebe an seinem klassischen...

stern-garage-shop.com

I don't know anything about the durability, but it's something to be considered at some point.

 

[500AMM]

The difference is that lets say when MB went to electronic engine cooling fan on a W211.

This is a very high powered electric fan possibly needing an alternator upgrade and heavy wiring feed.

Crucially, it is variable speed and controlled by the Engine ECU. I'm sure this monitors a variety of factors and it does speed up the fan gradually to control the engine temperature steadily.

Whereas where some aftermarket fans may have "variable adjustment" this still only relates to a sensor fitted which turns the fan on at a set / adjustable temperature point. On off control only. Which means that where the w211 MB fan is quiet in almost all conditions and maintains a perfect engine temperature, aftermarket electric fans on a w124 will only come on and roar when they are called for an off again. The result being a unhappy cooling system potentially as it is now also experiencing spikes in engine temperature by design of aftermarket control strategy.

Thanks Joe - and I definitely agree about the automatic variable speed feature.

 

[alabbasi]

Which means that where the w211 MB fan is quiet in almost all conditions and maintains a perfect engine temperature, aftermarket electric fans on a w124 will only come on and roar when they are called for an off again

I think that there are controllers available that offer a little more sophistication then just a temp probe. The kid that does side work for me has something like that on his W124 wagon. I believe that it's wired to the factory temp sensor and a/c pressure switches.

 

[JC220]

I think that there are controllers available that offer a little more sophistication then just a temp probe. The kid that does side work for me has something like that on his W124 wagon. I believe that it's wired to the factory temp sensor and a/c pressure switches.

This is good to know and would be interested to hear more on his setup.

Whilst aftermarket controls may be available in that regard would be good to know what parameters are adjustable. Presumably duty cycle setpoint at a given engine temperature.

Even so, not to sound negative but this would still only be effective coupled with a powerful OEM MB Electric engine cooling fan IMO. Fans which push massive CFM.

MB would have extensively tested and setup those later cars electric fans and control strategy in extreme environments. Most likely a freezer but also in desert conditions under full load for long hours etc. They know they work and are fit for purpose. Sadly the same comfort is not possible on retrofit solutions. It will always be a test it and see scenario with variable results depending on the environmental conditions.

Eg what may work for me over here would fail spectacularly in CA heat.

 

[alabbasi]

Most likely a freezer but also in desert conditions under full load for long hours etc.

That's Texas in February and August. I'll get the info from him. We were looking at using a W211 fan on my Jensen as the factory electric fans from 1973 are truly rubbish. I remember him talking about what he had and what was available.

IIRC, PWM's from a W202 C class can also be used.

 

[Jlaa]

Good point. I will ask. For what it is worth, I also hate all the noise that the OE electric fans make on high.

This is what Stern Garage said to me. Just passing on the facts:

• A larger alternator is usually not required. The electrical fan is not intended to run permanently, only to cushion temperature peaks when they appear for example in stop and go traffic. In those short run times, the battery can easily act as a power buffer and recharge when the electrical fan is off.
• The CFM rating of this fan is around 2020
• The fan will run on fixed speed
• We don't have an actual manual as this kit is a pretty straight forward fit.

 

[500AMM]

That's Texas in February and August. I'll get the info from him. We were looking at using a W211 fan on my Jensen as the factory electric fans from 1973 are truly rubbish. I remember him talking about what he had and what was available.

IIRC, PWM's from a W202 C class can also be used.

@alabbasi, did you progress on using a W211 fan? If so, how is it connected?

 

[alabbasi]

@alabbasi, did you progress on using a W211 fan? If so, how is it connected?

Bloody hell! We were standing in front of the Jensen yesterday and talking about it as i just got the block back. The company is called micro automations

 

[500AMM]

OK, a nice coincidence. So Micro Automations are looking into the el.fan transplant?

I guess the ECU gives the signal to the speed controller/unit sitting on the fan shroud, and it runs on 12V.

 

[Rouven036]

I have that setup on my W123 with the M117. 850W suction fan from SLS, works perfectly. Using 150A alternator.

 

[alabbasi]

OK, a nice coincidence. So Micro Automations are looking into the el.fan transplant?

I guess the ECU gives the signal to the speed controller/unit sitting on the fan shroud, and it runs on 12V.

look them up. They have a controller

 

[gsxr]

I have that setup on my W123 with the M117. 850W suction fan from SLS, works perfectly. Using 150A alternator.

Is it on/off, either full speed or nothing? Or do you have a variable speed controller?

 

[maw1124]

I think that there are controllers available that offer a little more sophistication then just a temp probe. The kid that does side work for me has something like that on his W124 wagon. I believe that it's wired to the factory temp sensor and a/c pressure switches.

I believe this is how the E46M crowd is running them as well. I’ll do some digging over there as I watch this.

maw

 

[Rouven036]

The micro automation controller does just that - perfectly. Connect engine temp sender (I used a output of the ecu and connected the unit there rather than directly onto the temp sender) ac aux fan switch, setup range/fan flow and there you go. Have a video I could share on WhatsApp from a function test with a heat gun

 

[500AMM]

Bloody hell! We were standing in front of the Jensen yesterday and talking about it as i just got the block back. The company is called micro automations

look them up. They have a controller

Micro Automations didn't lead anywhere, but Micro Autonomations did.
Fan Controller v3 + plug/harness + reset-able 50A fuse

 

[gsxr]

The video on their site is a great demo of why you don't want an electric fan switch on/off, either full speed or nothing. The noise is insane. This controller looks fantastic!

Anyone have dimensions for the compatible C-class fans? L x W x D? There is limited depth available on the W124 + M119 setups. I've walked past a bunch of these C-class in the junkyard in past years... d'oh...

Micro Autonomations

 

[alabbasi]

Micro Automations didn't lead anywhere, but Micro Autonomations did.
Fan Controller v3 + plug/harness + reset-able 50A fuse

View attachment 155186

Yeah that's what I said

 

[gsxr]

Related question: Why isn't SG using this setup? Factory fan + MA controller = hot setup.

 

[Rouven036]

They were somewhat hesitant. Talked to Raphael about that some year ago or so.
In hot country's the spal fans are certainly at the limit. Where of the brushless are absolutely sufficient. There is no other way than brushless. But you would need a capable setup like 850w or so and that fan costs around 700 dollar plus when I checked last time. Without controller, fitting shroud etc.

 

[yao500e]

This is what Stern Garage said to me. Just passing on the facts:

• A larger alternator is usually not required. The electrical fan is not intended to run permanently, only to cushion temperature peaks when they appear for example in stop and go traffic. In those short run times, the battery can easily act as a power buffer and recharge when the electrical fan is off.
• The CFM rating of this fan is around 2020
• The fan will run on fixed speed
• We don't have an actual manual as this kit is a pretty straight forward fit.

I am surprised Stern Garage didnt make this a PWM fan controller solution. A small PWM controller such as a Delta controller seems to work quite well.

 

[gsxr]

I am surprised Stern Garage didnt make this a PWM fan controller solution. A small PWM controller such as a Delta controller seems to work quite well.

Exactly. The Stern solution is, IMO, inadequate and sub-par. W124performance would never in a million years offer what Stern did/does.

 

[yao500e]

Exactly. The Stern solution is, IMO, inadequate and sub-par. W124performance would never in a million years offer what Stern did/does.

yes, i saw a youtube video, a guy with an early 1996 w202 benz, he took an Benz electric fan from facelifted 2nd gen w202 car, removed the clutch fan from his car, installed the benz electric fan right on the radiator, then installed a delta PWN device in the car and now he has a full modern electric fan solution with a Benz w202 fan. I would just keep the A/C front auxiliary fans too on top of this benz electric fan.

He got the benz w202 electric fan from a junk yard. The whole project probably took 5 hours and cost $150 USD total.

 

[Jlaa]

yes, i saw a youtube video, a guy with an early 1996 w202 benz, he took an Benz electric fan from facelifted 2nd gen w202 car, removed the clutch fan from his car, installed the benz electric fan right on the radiator, then installed a delta PWN device in the car and now he has a full modern electric fan solution with a Benz w202 fan. I would just keep the A/C front auxiliary fans too on top of this benz electric fan.

He got the benz w202 electric fan from a junk yard. The whole project probably took 5 hours and cost $150 USD total.

What is this Delta PWM device you speak of. Do you have a link? Thanks.

 

[yao500e]

What is this Delta PWM device you speak of. Do you have a link? Thanks.

The Delta current control.

http://www.dccontrol.com/constant_temperature_controllers.htm

And here is the w202 electric fan project.

Its 9 minutes and a good video. I think he could've just kept the front auxiliary fans stock set up.