HOW-TO: Replacing M104 (W463) Fan Clutch

[gerryvz]

Recently, I had an issue by where my 1994 G-Wagen (M104 engine) ran between 110C and 120C, particularly during uphill climbs and at slow speeds. After some research, I diagnosed the issue as a defective fan clutch.

Thus, replacement of the fan clutch was in order.

The MB part number for the fan clutch (as found in the G320 with M104) is the same as the normal M103/M104 part seems to be specific to the G-wagen version of the M104 -- 103 200 11 22. The current MB list price (as of June, 2014) is $292.00. The unit I received from MB was manufactured in Germany by Horton.

As FYI, the fan clutch as used in the M104s found in US-spec sedans and such, is 103 200 04 22. I do not know if this is interchangeable with the G-wagen's M104 fan clutch, but the MB documentation DOES ONLY specify the 103 200 11 22 part mentioned above for the G-wagen (Chassis and subtype 463.231).

Here is a photo pictorial of the steps required to remove and replace the fan clutch in a 1995 G320 (M104 gas engine). I hope this is helpful to someone in the future.


Tools required are:

• a 90-degree hooked awl-type tool;
• a flat-blade screwdriver;
• a 7mm Allen key (long is better);
• and the special 7mm MB "stubby" socket for the fan clutch bolt (this is not required but makes the job a bit easier).

It's also a good idea, before starting the job, to insert a piece of cardboard on the backside of the radiator to protect the fins from any accidental bumping or gouging from the Allen key and socket used to remove the fan clutch center bolt.


Key steps:

Here's an overview of the fan clutch area.




Remove the fan shroud by releasing the top retainer.



Twist the smaller (rear) portion of the fan shroud and move it backward over the fan toward the cylinder head. Remove the two metal fan shroud retaining clips on the sides of the shroud. A small or medium flat-blade screwdriver makes this job a simple flick of the wrist.



Carefully lift the larger (front-most) portion of the fan shroud upward and lift it out of the engine compartment



Move the smaller portion of the fan shroud forward off of the fan, and lift it out of the engine compartment.



Using the 90-degree hooked tool, wedge the end of the tool through one of the holes in the base of the emergency pin piece and in between two of the aluminum fan clutch blades. Turn the fan slightly to solidly wedge the tool in place.



Carefully insert the short end of the Allen key into the center fan clutch bolt. Turn the Allen key counter-clockwise (as you face the radiator from the front of the vehicle) and loosen the center bolt, holding the handle of the hooked tool in the other hand to keep it securely wedged into place.



Remove the Allen key and insert the stubby MB socket into the center fan clutch bolt. Turn the socket with your fingers in a counter-clockwise direction to remove and then extract the bolt. If you don't have this socket, you can remove the bolt with more turns of the Allen key, until you can grip the head of the bolt with your fingers to remove it.



Remove the bolt and then CAREFULLY wiggle the fan/clutch assembly back and forth to loosen it from the pulley. DO NOT let the fan/clutch assembly touch the back of the radiator so as to avoid damage to the radiator and/or cardboard protecting the fins.



Once the fan/clutch assembly is removed, use a 5mm Allen key to loosen and remove the three bolts holding the clutch to the fan.



Use brake cleaner or other solvent to clean the fan assembly, as needed.



Re-install the clutch into the fan, and then the fan/clutch back onto the front of the motor, using the reverse of the previously outlined steps.




Cheers,
Gerry

 

[gerryvz]

I replaced the fan clutch again yesterday on the G320. It seems that the clutch that I installed back in 2014 has leaked out some of its fluid, and its effectiveness has been wanting for the past year or so.

Same part number and all ... the process only took 15 minutes to do, fortunately.

It seems that the "thin" fan clutches for various motors don't seem to be as reliable or as good at holding fluid as the "thick" fan clutches like the one used with the E500E.

I'm driving the 30 miles to Washington Reagan Airport now, and will test out the new clutch to see how effective it is at controlling coolant temps.

 

[Klink]

It seems that the "thin" fan clutches for various motors don't seem to be as reliable or as good at holding fluid as the "thick" fan clutches like the one used with the E500E.

Exactly my experience over the years. Then again, there were so many of the thick ones that were so poorly calibrated with many barely working at all...

 

[gerryvz]

A few fan clutch photos....

Here is the MB factory fan clutch that I replaced back in 2014, front and rear views:




Here is a comparison of the old and new production factory fan clutches, side by side. Obviously, the new clutch is on the right side of the photo.



Cheers,
Gerry

 

[Seangbadee]

Recently, I had an issue by where my 1994 G-Wagen (M104 engine) ran between 110C and 120C, particularly during uphill climbs and at slow speeds. After some research, I diagnosed the issue as a defective fan clutch.

Thus, replacement of the fan clutch was in order.

The MB part number for the fan clutch (as found in the G320 with M104) is the same as the normal M103/M104 part -- 103 200 11 22. The current MB list price (as of June, 2014) is $292.00. The unit I received from MB was manufactured in Germany by Horton.


Here is a photo pictorial of the steps required to remove and replace the fan clutch in a 1995 G320 (M104 gas engine). I hope this is helpful to someone in the future.


Tools required are:

• a 90-degree hooked awl-type tool;
• a flat-blade screwdriver;
• a 7mm Allen key (long is better);
• and the special 7mm MB "stubby" socket for the fan clutch bolt (this is not required but makes the job a bit easier).

It's also a good idea, before starting the job, to insert a piece of cardboard on the backside of the radiator to protect the fins from any accidental bumping or gouging from the Allen key and socket used to remove the fan clutch center bolt.


Key steps:

Here's an overview of the fan clutch area.
View attachment 27815



Remove the fan shroud by releasing the top retainer.
View attachment 27814 View attachment 27813


Twist the smaller (rear) portion of the fan shroud and move it backward over the fan toward the cylinder head. Remove the two metal fan shroud retaining clips on the sides of the shroud. A small or medium flat-blade screwdriver makes this job a simple flick of the wrist.
View attachment 27820


Carefully lift the larger (front-most) portion of the fan shroud upward and lift it out of the engine compartment
View attachment 27816 View attachment 27817


Move the smaller portion of the fan shroud forward off of the fan, and lift it out of the engine compartment.
View attachment 27818


Using the 90-degree hooked tool, wedge the end of the tool through one of the holes in the base of the emergency pin piece and in between two of the aluminum fan clutch blades. Turn the fan slightly to solidly wedge the tool in place.
View attachment 27819 View attachment 27821


Carefully insert the short end of the Allen key into the center fan clutch bolt. Turn the Allen key counter-clockwise (as you face the radiator from the front of the vehicle) and loosen the center bolt, holding the handle of the hooked tool in the other hand to keep it securely wedged into place.
View attachment 27822 View attachment 27823


Remove the Allen key and insert the stubby MB socket into the center fan clutch bolt. Turn the socket with your fingers in a counter-clockwise direction to remove and then extract the bolt. If you don't have this socket, you can remove the bolt with more turns of the Allen key, until you can grip the head of the bolt with your fingers to remove it.
View attachment 27824 View attachment 27825 View attachment 27826


Remove the bolt and then CAREFULLY wiggle the fan/clutch assembly back and forth to loosen it from the pulley. DO NOT let the fan/clutch assembly touch the back of the radiator so as to avoid damage to the radiator and/or cardboard protecting the fins.
View attachment 27827 View attachment 27828


Once the fan/clutch assembly is removed, use a 5mm Allen key to loosen and remove the three bolts holding the clutch to the fan.
View attachment 27829 View attachment 27830 View attachment 27831 View attachment 27832


Use brake cleaner or other solvent to clean the fan assembly, as needed.



Re-install the clutch into the fan, and then the fan/clutch back onto the front of the motor, using the reverse of the previously outlined steps.
View attachment 27833 View attachment 27834 View attachment 27835 View attachment 27836 View attachment 27837 View attachment 27838 View attachment 27839 View attachment 27840 View attachment 27841



Cheers,
Gerry

Gerry I'm planning to change out my viscous fan very soon, and I have been looking around at getting the 'tropical' version used in hot climates.
Going through the mboem catalog, I found the version for $$$, but there's a note that says it will not work in my 95 E320.
I'm not interested in the 'band-aid' cooling harness approach, but rather want to make sure I have everything set as stock as possible
I have attached the part numbers hoping you can shed some more light on this.
Thanks
Sean

 

[gerryvz]

DO NOT get the "tropical" version of said clutch. It is absolutely not needed, if everything is running correctly and to spec.

While I had a defective fan clutch, as indicated, some time after replacing it, long around early 2018, I started having hot-running issues again with the engine. I replaced the fan clutch YET AGAIN with a new factory model, and it didn't solve the problem. I purchased a new water pump, in anticipation of also having to replace it being original and defective. I had also replaced the original radiator with a new Nissens radiator, again in anticipation that the radiator was somehow clogged or plugged. This wasn't a bad thing to do proactively, as the original 25-year old radiator had 120+K miles on it and was probably nearing the end of its service life, anyway.

In the course of diagnosing things, I also found that I had a defective electric fan thermo-sensor, which was not turning on the low-speed of the electric fan (though the high speed at high temps did turn on). So for example, when I was running the A/C under most conditions, the low-speed fan would not be running.

The issue turned out to be a defective thermostat. Replacing that thermostat earlier this year ABSOLUTELY and DEFINITIVELY solved my cooling problems. I cannot make the temperature gauge climb above 90-95C AT ALL, under any conditions, since doing this. Even in summer heat/humidity, sitting for 5 minutes at a stoplight, it will get just to 100C, but NEVER over.

What's most important when diagnosing cooling problems, is to determine WHAT is happening under WHAT conditions. There is a different set of conditions that happen when the fan clutch is defective, as opposed to when the thermostat is defective and/or when the water pump is defective or when the radiator is defective.

Would be best to describe your situation and observations here, and then we can help diagnose it. I went through a LOT of parts, some of them expensive, diagnosing what turned out to be a bad thermostat.

Like I said though, I honestly NEVER have issues anymore with the cooling system in any conditions. It generally sits at 85-87C indiciated temp when the truck is running, and it's difficult to budge it off of that mark anymore. I suffered for a LONG time with a hot-running truck (105-115C running temps). Yesterday I was in Atlanta for the day (ATL up to Kennesaw, then back to ATL) and last night at 11 PM, all the 75 miles from Dulles Airport to Annapolis, the temp sat at 87C the full distance.

Also one more note, the G-wagen's M104 engine has a special part on it behind the fan that the regular ("pedestrian") E320 sedan/wagon/coupes don't have, which is the "star" plate that I hooked the tool into to hold the fan (no special fan holder tool needed). This is an addition for "field emergencies" with the G-wagen so in case the fan clutch fails, you can bend the prongs of the star plate to engage the fan 100% for cooling to get you home. Those Germans thought of everything for the military-wannabe/utilitarian early G-wagens !!!

For the E320 sedans/wagons, I have two examples of the special fan holding tool (basically a bent piece of thick metal wire) though I have also used a double-bent piece of coat hanger before I got the tool. That works in a pinch. The tool is available cheaply on the aftermarket or eBay, or from MB (it's even relatively cheap from MB).

 

[Seangbadee]

Wow, that's big "DO NOT" and your advice will be heeded. Right now I do not have any issues because the car is not on the road. From the day I purchased it, back in August, I drove it twice from Kennesaw to Smyrna, and then to Loganville. It has not moved from Loganville, where I am doing my repairs.
I was being proactive and I'm glad I brought up the subject. The fans go on low when you first switch the AC on, and as it gets hotter then run higher.
No issues with the cooling system, however I have zero maintenance records. The car however appears extremely well maintained.
I did a complete overhaul on my M103, and remember I always had to use a bent Allen key (self-fabricated) which I inserted into a hole behind the fan, to stop it from moving. Since I've never worked on an M104 until now; I wonder if it's the same method.
Once I have uncoupled and coupled the front suspension back, I hope I will be able to start driving the car. I have a whole lot of parts coming in from mboem, fcp and autohauz. Quite a bit of work still to be done, bit once done I will come back to this feed to let everyone know how the cooling system is performing.
I have a strong feeling however that I may need to change the fan because the previous owner had a replacement in the trunk from somewhere called hamburgworks (it looks like a knock off).
Not to worry I am going for OE from MB.

 

[gsxr]

That Hamburglar Tech clutch may be useful for testing purposes, as it may be fully engaged almost all the time. This should allow you to see how cool engine temps are with a clutch engaged constantly. But I wouldn't leave it installed long-term. Note the factory 6-cyl clutches tend to engage at higher temps than some people would like, but this isn't necessarily bad. It can make testing difficult in cooler temps though.

If you have no record of the thermostat being replaced, do that first, as GVZ mentioned. It's good preventive maintenance and cheap insurance. IMO the t-stat should be changed about every other coolant change (i.e., every 7-10 years). Remember to use Zerex G-05 (yellow/gold color) antifreeze, no green or orange stuff! If you have time, pull the radiator and clean out the debris between the condenser & radiator, and blow out both units with compressed air.

Disclaimer: The M119 clutches are a completely different design and separate discussion, covered in detail in old threads on the forum.

 

[Seangbadee]

I will make sure I change the thermostat today I believe I got a Wagner thermostat from FCP, I hope this is a good one.
The previous owner was using zerex go5, so I guess I'm good to continue with that

Thanks for all your help

Sean

 

[gerryvz]

ONLY use Behr or Wahler thermostats. No Wagner or other US domestic brands.

The M103 and M104 use the same fan hub holding tool, so your allen key setup should work OK.

That Hamburg Tech clutch should be tossed as far away (like a frisbee) as possible. Perhaps onto your neighbor's property, or into the woods, where it can rust and die in peace.

ONLY use Behr or MB OE fan clutches for the M103/M104. I would hold out for the MB clutch, but a German-made Behr would be OK too.

https://www.autohausaz.com/pn/1032000422

Search for '1032000422' | FCP Euro

parts online. Buy OEM & Genuine parts with a Lifetime Warranty, Free Shipping and Unlimited 365 Day Returns.

www.fcpeuro.com

Search Results | MB OEM Parts

www.mboemparts.com

 

[gsxr]

I think you mean Borg-Warner? They are claiming it's a reboxed Wahler, which should be fine. I think the OE unit is Behr but FCP does not carry that one in aftermarket form. You did the right thing by *not* buying Meyle.

https://www.fcpeuro.com/products?keywords=1102000515

AHAZ and RME both have the Behr (reboxed as Mahle). AHAZ generally doesn't have the brands I want, or they are priced too high, so I buy a lot from RME now that Importec closed:

https://www.rmeuropean.com/Make/PartNumberSearch.aspx?pnsearch=1102000515

https://www.autohausaz.com/pn/1102000515

 

[Seangbadee]

ONLY use Behr or Wahler thermostats. No Wagner or other US domestic brands.

The M103 and M104 use the same fan hub holding tool, so your allen key setup should work OK.

That Hamburg Tech clutch should be tossed as far away (like a frisbee) as possible. Perhaps onto your neighbor's property, or into the woods, where it can rust and die in peace.

ONLY use Behr or MB OE fan clutches for the M103/M104. I would hold out for the MB clutch, but a German-made Behr would be OK too.

https://www.autohausaz.com/pn/1032000422

Search for '1032000422' | FCP Euro

parts online. Buy OEM & Genuine parts with a Lifetime Warranty, Free Shipping and Unlimited 365 Day Returns.

www.fcpeuro.com

Search Results | MB OEM Parts

www.mboemparts.com

I think I made a mistake, the thermostat is Borg Warner and not "Wagner".
It's made in Germany, but if this is a "no-no" I'll return it to FCP
Thanks

 

[gsxr]

FCP says it's Wahler. It should be fine. Wahler is an OEM for some MB parts.

 

[Seangbadee]

Great. Thank you. The thermostat will be replaced and completed today.
One less job to do.
What are your thoughts on the BEHR radiators from South Africa?. I used one before (from FCP) in my 91 300E, with no issues at all before I eventually sold the car. The only thing was I "rigged" the temperature sensor with a 1.1Kohm resistor, and the fans would come on all the time. I'm not doing this with my E320.

 

[Seangbadee]

ONLY use Behr or Wahler thermostats. No Wagner or other US domestic brands.

The M103 and M104 use the same fan hub holding tool, so your allen key setup should work OK.

That Hamburg Tech clutch should be tossed as far away (like a frisbee) as possible. Perhaps onto your neighbor's property, or into the woods, where it can rust and die in peace.

ONLY use Behr or MB OE fan clutches for the M103/M104. I would hold out for the MB clutch, but a German-made Behr would be OK too.

https://www.autohausaz.com/pn/1032000422

Search for '1032000422' | FCP Euro

parts online. Buy OEM & Genuine parts with a Lifetime Warranty, Free Shipping and Unlimited 365 Day Returns.

www.fcpeuro.com

Search Results | MB OEM Parts

www.mboemparts.com

I promise to discard the HamTech as soon as yesterday. My neighbours are good, so there'll be no frisbee throwing.
Thanks again.

 

[gsxr]

Behr radiators from South Africa are the good ones... same as you'd get from the MB dealership.

Behr radiators from China are the ones to be concerned about. If radiator shopping and you see two Behrs offered at the same vendor with different pricing, the cheaper one is from China. On my W210, I gambled on the cheap Chinese unit, so far it hasn't failed... but it's only been a year or two.

Running the electric fans all the time on high is not a good idea, and not necessary if the cooling system is working normally. This is usually a band-aid to cover up some other problem, OR to pacify owners with unreasonable expectations of how cool the engine should run. Lots of discussion on this in the past.

 

[gerryvz]

Behr radiators (as @gsxr said, non-China) and Nissens (made in Denmark) are both good bets, generally.

I am running Nissens radiators in my G320 and for some years now in my E500 with zero issues. The Nissens radiator for the E500E takes a very slight modification, as I detailed in my HOW-TO. I don't think the Behr requires any mods. In any case, it's a 10-minute mod, so no big deal.

 

[Glen]

Out of curiosity, I searched Autohausaz for radiators and they currently have a sale for a Behr unit for $119.96. Seems too good to be true...is this the Chinese version?

Mahle Behr 1245001402, 70826327 Radiator - Mercedes | 1245000302 376712271 376712273 376712274

Find Mahle Behr, 70826327 Radiator 1245001402 at discount prices in our extensive Mercedes auto parts catalog. AutohausAZ offers a large selection of Mahle Behr parts online. 1 per car. Fits Mercedes E500, E420, 400E, 500E. 1245000302 376712271 376712273 376712274 70826327 CR283000S W0133-1598786

www.autohausaz.com

 

[gsxr]

$120 is almost certainly Chinese. Note this is for the 400E radiator, 124-500-14-02.

RM European has the Behr for $250 which is much more likely to be of SA origin:
https://www.rmeuropean.com/Make/PartNumberSearch.aspx?pnsearch=1245001402

The OE/dealer unit is $510 list / $375 discount, ouch.
https://www.mboemparts.com/oem-parts/mercedes-benz-radiator-1245001402


The 500E radiator is a different p/n, 124-500-03-02, which is cheaper from the dealer: $354 list, $265 discount. I was never able to determine the difference between them.

 

[Seangbadee]

$120 is almost certainly Chinese. Note this is for the 400E radiator, 124-500-14-02.

RM European has the Behr for $250 which is much more likely to be of SA origin:
https://www.rmeuropean.com/Make/PartNumberSearch.aspx?pnsearch=1245001402

The OE/dealer unit is $510 list / $375 discount, ouch.
https://www.mboemparts.com/oem-parts/mercedes-benz-radiator-1245001402


The 500E radiator is a different p/n, 124-500-03-02, which is cheaper from the dealer: $354 list, $265 discount. I was never able to determine the difference between them.

I found the BEHR (South Africa) at FCP. I'll buy this one. I've heard good things about Nissens as well from one of the forum members, but I'll go with BEHR.
Thanks everyone

 

[yao500e]

Recently, I had an issue by where my 1994 G-Wagen (M104 engine) ran between 110C and 120C, particularly during uphill climbs and at slow speeds. After some research, I diagnosed the issue as a defective fan clutch.

Thus, replacement of the fan clutch was in order.

The MB part number for the fan clutch (as found in the G320 with M104) is the same as the normal M103/M104 part seems to be specific to the G-wagen version of the M104 -- 103 200 11 22. The current MB list price (as of June, 2014) is $292.00. The unit I received from MB was manufactured in Germany by Horton.

As FYI, the fan clutch as used in the M104s found in US-spec sedans and such, is 103 200 04 22. I do not know if this is interchangeable with the G-wagen's M104 fan clutch, but the MB documentation DOES ONLY specify the 103 200 11 22 part mentioned above for the G-wagen (Chassis and subtype 463.231).

Here is a photo pictorial of the steps required to remove and replace the fan clutch in a 1995 G320 (M104 gas engine). I hope this is helpful to someone in the future.


Tools required are:

• a 90-degree hooked awl-type tool;
• a flat-blade screwdriver;
• a 7mm Allen key (long is better);
• and the special 7mm MB "stubby" socket for the fan clutch bolt (this is not required but makes the job a bit easier).

It's also a good idea, before starting the job, to insert a piece of cardboard on the backside of the radiator to protect the fins from any accidental bumping or gouging from the Allen key and socket used to remove the fan clutch center bolt.


Key steps:

Here's an overview of the fan clutch area.
View attachment 27815



Remove the fan shroud by releasing the top retainer.
View attachment 27814 View attachment 27813


Twist the smaller (rear) portion of the fan shroud and move it backward over the fan toward the cylinder head. Remove the two metal fan shroud retaining clips on the sides of the shroud. A small or medium flat-blade screwdriver makes this job a simple flick of the wrist.
View attachment 27820


Carefully lift the larger (front-most) portion of the fan shroud upward and lift it out of the engine compartment
View attachment 27816 View attachment 27817


Move the smaller portion of the fan shroud forward off of the fan, and lift it out of the engine compartment.
View attachment 27818


Using the 90-degree hooked tool, wedge the end of the tool through one of the holes in the base of the emergency pin piece and in between two of the aluminum fan clutch blades. Turn the fan slightly to solidly wedge the tool in place.
View attachment 27819 View attachment 27821


Carefully insert the short end of the Allen key into the center fan clutch bolt. Turn the Allen key counter-clockwise (as you face the radiator from the front of the vehicle) and loosen the center bolt, holding the handle of the hooked tool in the other hand to keep it securely wedged into place.
View attachment 27822 View attachment 27823


Remove the Allen key and insert the stubby MB socket into the center fan clutch bolt. Turn the socket with your fingers in a counter-clockwise direction to remove and then extract the bolt. If you don't have this socket, you can remove the bolt with more turns of the Allen key, until you can grip the head of the bolt with your fingers to remove it.
View attachment 27824 View attachment 27825 View attachment 27826


Remove the bolt and then CAREFULLY wiggle the fan/clutch assembly back and forth to loosen it from the pulley. DO NOT let the fan/clutch assembly touch the back of the radiator so as to avoid damage to the radiator and/or cardboard protecting the fins.
View attachment 27827 View attachment 27828


Once the fan/clutch assembly is removed, use a 5mm Allen key to loosen and remove the three bolts holding the clutch to the fan.
View attachment 27829 View attachment 27830 View attachment 27831 View attachment 27832


Use brake cleaner or other solvent to clean the fan assembly, as needed.



Re-install the clutch into the fan, and then the fan/clutch back onto the front of the motor, using the reverse of the previously outlined steps.
View attachment 27833 View attachment 27834 View attachment 27835 View attachment 27836 View attachment 27837 View attachment 27838 View attachment 27839 View attachment 27840 View attachment 27841



Cheers,
Gerry

very informative and helpful. My buddy changed his m104 e320 to an electric fan. I'm thinking of doing the same with my C36 M104 and while im at it, might install a Ross Harmonic damper too.