Viscous Fan Clutch Replacement

[gerryvz]

You don’t have to, if you shorten an Allen key end to insert into the fan clutch bolt to clear the radiator.

The problem is that there is often not enough leverage and space to fully insert the shortened Allen key end into the bolt, or if this is done, not enough leverage to loosen a very tight/stuck fan clutch bolt.

This bolt is HIGHLY prone to accidental strippage.

However it is strongly advised to remove the radiator, even if just to protect it from accidental damage. There is a HOW-TO on doing this, and it’s only a 20-30 minute job to remove. It also gives an opportunity to inspect and clean the radiator, if necessary, due to cloggage with dirt and stuff.

Removing the radiator allow you to get a straight shot to the fan clutch bolt to apply enough leverage to loosen it and help avoid stripping it.

Also, removing the radiator is great outlet in case your “lowmania” disease has flared up that day.

 

[gsxr]

Is it true that on our .036’s you have to remove the radiator to replace the fan clutch due to not enough space between the fan clutch and the radiator?

It's possible with special tools, if the bolt head is not stripped, and the bolt is not excessively tight. Otherwise, the radiator would need to come out.

See post #2 and #4 at the beginning of this thread for photos of the special tools. After it's been R&R'd once and all the fasteners cleaned up, it's possible to remove the fan+clutch in 5-10 minutes. Clearance to the radiator varies due to manufacturing tolerances, it goes faster on cars with a bit more space. Typical is about 24mm air gap from the radiator fins to the plastic cover on the face of the clutch, ±2mm or so.

 

[gerryvz]

I have used M119 and M104 (both E320 and G320) fan clutches close at hand. I will make some measurements on key things and dimensions and report back.

One difference right off the bat, is that the M103/M104 fan clutch has three bolts that hold it onto the fan, while the M119 fan clutch uses four bolts. Photos coming soon.

Cheers,
Gerry

 

[Kyiv]

How long does the job of replacing fan clutch takes with radiator in place and with out, assuming it's done by someone who know what he's doing?

 

[jhodg5ck]

How long does the job of replacing fan clutch takes with radiator in place and with out, assuming it's done by someone who know what he's doing?

Hour should be ample if you have the special tools allowing for time to clean things up some etc..

Now this is also assuming the fan shroud wants to cooperate/the front end hasn't been smacked.

Jono

Sent from my SM-G960U using Tapatalk

 

[mikeym]

You got me here! I didn't think about rotation at all... Maybe someone with M104 can chime in here? If I ever go that route I will definitely replace the whole set - fan + clutch. My current aftermarket clutch is skinny already, I have no idea what brand PO installed but I have no doubts it is a cheap Chinese knock off.

Saying "reasonable" I mean 2-3 times more than other aftermarket clutches. It costs pretty much the same ($130) as ACM in US.

Regarding M104 clutch, if you buy it from the dealer, it is a Behr brand made in China unit. So, might as well buy Behr aftermarket for 1/2 the price.
I was able to get Sachs Made in Germany clutch but it is the tropical version from a dealer in Abu Dabhi. AutohausAZ used to be able to source Sachs but not anymore.

 

[gerryvz]

Are you sure the Behr units from MB dealers are made in China? I recently ordered a new M104 fan clutch for my G320 (it's a slightly different part number than the regular M104s as used in the 124 models). It was a Sachs/Horton unit, and the label on the MB box said "Made in Germany."

I know the current factory clutches for the M119 are also Sachs/Horton and made in Germany.

 

[mikeym]

Are you sure the Behr units from MB dealers are made in China? I recently ordered a new M104 fan clutch for my G320 (it's a slightly different part number than the regular M104s as used in the 124 models). It was a Sachs/Horton unit, and the label on the MB box said "Made in Germany."

I know the current factory clutches for the M119 are also Sachs/Horton and made in Germany.

Yup, ordered one from the dealer and it was Chinese Behr. Returned it next day.

Below is the line item from the order that I had placed:
103 200 04 22 fan drive list $280.00ea cost $210.00ea new only

 

[Kyiv]

This is most likely useless info, but just in case:

ACM, made in China by NSK. From the latest batch




Once, original MB fan clutch that is 4 years old, but has only 7k miles on it, comes out, can it be recycled, "adjusted", reused in any way, or is it a loss?

 

[gsxr]

How odd... ACM label on a Borg-Warner box. Hmmm. Once you get it installed and finish testing the cooling/airflow performance, I'm curious if it will disengage at high RPM. Older ACM clutches would do so, at a higher RPM than stock, but would disengage. Vemo (the only other brand I tested) refused to disengage even at redline, making for noisy WOT runs.

The original clutch can be adjusted to work properly, but it's a very tedious trial & error process, with a high risk factor (i.e., if you mess it up, it can destroy the clutch + radiator).

In the meantime I can't wait to hear what happens when you get the ACM in there!

 

[MB V8]

I just put the same ACM fan clutch on my 400E. I remember looking it over pretty carefully, but don't recall seeing anything regarding being manuf. in China by NSK. Where did you get that info? Is it on one of the labels on the Borg Warner piece of cardboard?

 

[Kyiv]

Gsxr, yes, Borg Warner box, inside this part in cellophane with a sticker ACM Germany. BTW, going to junkyard in Baltimore in my 400E I, for the first in a very long time, was able to drive at 80 mph for stretches at a time, in light traffic, in sub 60f. Coolant temp stayed at 82-85C when I was moving fast and freely

MB V8, Zoom in on the orange circle by the center of clutch. You'll see NSK and China stamped. How do you like the result of the new clutch?

 

[Jlaa]

How odd... ACM label on a Borg-Warner box. Hmmm. Once you get it installed and finish testing the cooling/airflow performance, I'm curious if it will disengage at high RPM.

Gsxr, yes, Borg Warner box, inside this part in cellophane with a sticker ACM Germany.

I installed an ACM fan clutch almost exactly two years ago. It also came in a Borg Warner box. The bearings were marked NSK and made in China.
The ACM fan clutch I installed does indeed cut out at higher RPMs, although I never made a note to mark exactly at what RPM.
It has proven to be quite satisfactory in operation for me. That said, since I live in Northern California, the climate here is not exactly thermally challenging for the 500E.

 

[Kyiv]

So, ACM fan clutch resolved my running-warmer-then-proper issue. Good stuff

[Admin edit: Details in this post.]

 

[gerryvz]

Link to the G-wagen fan clutch replace thread is located here: https://www.500eboard.co/forums/index.php?threads/how-to-replacing-m104-w463-fan-clutch.5800/

 

[darek_u]

I installed the M104 clutch successfully in 500E so I can share some info. The clutch I used is original and German made Behr clutch:



Fan - due to different bolt pattern (M104 used 3 bolts vs. M119 clutch uses 4 bolts) fan needs to be replaced. I was thinking about fabricating some kind of adapter plate using CNC and keep using the original magnesium fan but gave up on that. My first attempt was fan from 2.1D Sprinter - these are widely available and supercheap in Europe. Part number is 1032000423 but it turned out that it is smaller in diameter, not much, maybe 5mm but I didn't like it. I also didn't like the colour but this is very minor... Next I turned my attention to V8 powered ML truck fan - bingo! Fan part number 11320000223 is a perfect match. I got it almost for free ($15) and in perfect condition - part is widely available here. It has identical diameter, same shape of fins and it's black instead of yellow:



Installation is almost P&P. If your car originally had OE (thick) clutch it is necessary either to shorten the original bolt or purchase the new bolt from the hardware store as new clutch is "skinny" type. In my case bolt was already shortened as PO installed crappy Meyle part - no wonder that the car sounded like taking off Jumbo Jet when accelerating;



If you decide to shorten the original bolt you will have to use a spacer (washer) between bolt and the clutch - the non-threaded part of the bolt is just little bit too long for the new clutch. In my case use of 2 washers was enough, they formed 3mm spacer. I found these in Porsche parts stash, perfect fit, no play at all, very tight, just like they would be made for this application See below the original bolt shortened and spacer (washer) next to it - smaller one, the big washer was not used.



After installation the new assembly sits 5mm closer to the engine than the original fan. I wanted to use another spacer (2mm thick) to move it away but decided it didn't matter and wasn't necessary. Fit is perfect with regards to fan shroud and other elements in front of the engine. I run the engine twice for some time and it behaves just like a proper clutch I think - car is still on Quick Jack so no road test yet. It's night and day compared to Meyle in terms of sound. Installed:

 

[JC220]

Has anyone ever used a NRF m119 viscous fan clutch?

I want a new one to fit into my S500 since it is all apart anyway. It seems like it's not a budget brand and from what I have read online even the Behr for PN A1192000022 is made in China now....

 

[Seangbadee]

How odd... ACM label on a Borg-Warner box. Hmmm. Once you get it installed and finish testing the cooling/airflow performance, I'm curious if it will disengage at high RPM. Older ACM clutches would do so, at a higher RPM than stock, but would disengage. Vemo (the only other brand I tested) refused to disengage even at redline, making for noisy WOT runs.

The original clutch can be adjusted to work properly, but it's a very tedious trial & error process, with a high risk factor (i.e., if you mess it up, it can destroy the clutch + radiator).

In the meantime I can't wait to hear what happens when you get the ACM in there!

It was a beautiful 56 degrees in Atlanta, and I decided to do some work on my car. I felt it sounded a bit 'noisy'; it wasn't the valve train but sounded like it was coming from between the fan and the power steering pump.
Anyway curious as I always am, I decide to take a further look and discovered that only 1 of the 2 auxillary fans was working. I was surprised that the minute I touched the second one (passenger side) with my hand, It would start to work.
Without any hesitation I decided to remove the fans (quite a job), only to discover a mass of dried up leaves, pine needles etc in between the fans and the condenser. By the time I got the fans out and inspected them, the failing fan had so much debris inside the back. I used compressed air, got all the debris out, lubricated both fans, tested them and they are both working.
I removed the serpentine belt, and discovered the following:
The smog pump bearings are worn,
1 bolt on the fan was almost off completely from its attachment to the viscous body,
All bolts on the cooling fan pulley were loose
Bad idler pulley (cracked and noisy).
Tension pulley is very noisy
Power steering was okay.
No noise from alternator pulley.
AC compressor ~ need to check that.
I decided not to couple anything until I go over the car one more time.
I have no clue how to check if the viscous fan is okay but that will wait till another day.
In the meantime, I'm glad I went nosing around.

 

[Seangbadee]

Is this considered a good replacement!

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

www.fcpeuro.com

 

[gsxr]

Is this considered a good replacement!

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

www.fcpeuro.com

I'd only replace the fan clutch if the existing one isn't working (or, is a no-name of questionable quality). The clutch can be difficult to test unless ambient temps are warm, like 80-90F. The clutch needs hot air to engage.

The Mahle/Behr unit is probably made in China. Personally, I'd prefer OE/OEM Horton/Sachs. If the Behr is really made in Germany, that is a great deal. I have a feeling FCP's site may not be up to date.

 

[gsxr]

Dunno if this is for realz, but Napsterville is showing a "reman" OE M104 clutch for $107 delivered...

Remanufactured-Luefterantrieb 103-200-04-22-81 | MB OEM Parts

103-200-04-22-81 - Remanufactured-Luefterantrieb

www.mboemparts.com

 

[Seangbadee]

What I notice is that as the car gets hot, the fan seems to blow louder without engaging the auxillary fans.
Does this means that the clutch is good/engaging?
I wouldn't want to have to do this job twice, and would prefer just to put a new one in.

 

[gsxr]

What I notice is that as the car gets hot, the fan seems to blow louder without engaging the auxillary fans.
Does this means that the clutch is good/engaging?

Yes, that is how it works. The clutch lets the fan blade freewheel (spin slower than the engine pulley) until the air temp ahead of the clutch is high enough to engage it. When the clutch engages, the fan spins at pulley speed and will roar, which is louder than normal.

The electric fans run on low speed when refrigerant pressure exceeds 16 bar (the fans don't always run when the AC is on).
The electric fans run on high speed when engine temp exceeds 107°C.

The mechanical fan clutch generally engages with engine temps around 90-95C in warm ambients. Many variables can affect how & when the clutch engages, so don't take this as gospel. And, the fan clutch is an analog device - it can be partly engaged, and disengage above a certain RPM (which may be below the max RPM of the clutch where it always disengages regardless of temperature). Read some of the old threads on the forum discussing the fan clutch, just keep in mind your M104 clutch is constructed differently, and some of the M119 clutch complaints (mostly mis-calibrated new clutches) shouldn't apply to the M104.

 

[Seangbadee]

In that case, I will put the one I have back in, because it's obviously working..
If it isn't broken.......
Thanks for the input

 

[Kyiv]

Is this considered a good replacement!

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

Mercedes Cooling Fan Clutch - Mahle Behr 1032000422

www.fcpeuro.com

Per FCP, under description, says this unit is made in Germany. I wish there was a German made fan clutch for W124 V8 models for $90

 

[gsxr]

Per FCP, under description, says this unit is made in Germany. I wish there was a German made fan clutch for W124 V8 models for $90

I'm pretty sure that is an error on FCP's website. All the Behr clutches I've seen in the past 5+ years have been made in China.

But yeah, we don't have any cheap options for the M119.

 

[Seangbadee]

I have more noisy bearings here on my 95 E320. One on the tensioner, and another on the cooling fan assembly. Not only is the latter noisy, it has some clearance and is slightly wobbly.
Do I change out these bearings, or just replace the parts?

 

[gsxr]

If the bearing in the fan support bracket is bad, replace the entire assembly... besides, yours is damaged, the edge of the notch for the lock tool is broken off. Only buy the OE/dealer bracket. Photos here:
http://www.w124performance.com/images/M104_stuff/fan_bracket_OE_104-200-13-28/

Note one of the the bolts require using anaerobic sealant on the threads, or you will have an oil leak. I used sealant on all the bolts just to be safe. This is often missed in the FSM procedure:
http://www.w124-zone.com/downloads/MB CD/W124/w124CD1/Program/Engine/104/20-3140.pdf

Here's my sob story from summer 2014 on this particular job. Photos of the failed bracket are at this link. Febi is now very high on my naughty list, btw.

Febi is rapidly moving up my naughty list. ​

​

My new-to-me S124 wagon had a record of the M104 fan bearing bracket being replaced by a shop a few years ago. The receipt shows the shop charged the previous owner full MB dealer retail at the time for the bracket ($278)... but they installed a Febi bracket instead. The Febi bracket failed in 4 years / 38kmi, the bearing was loose in the casting and allowed the pulley to move forward/aft 2-3mm. ​

​

The Febi bracket was made in Germany, btw... no Chinese stuff here. Apparently Febi can't even make quality stuff in Germany! It is also sad that a shop would charge a customer dealer retail, and then install a part which they probably paid 1/3 as much for. As a bonus, the shop did not install it correctly, they did not use anaerobic sealant on the bolts during installation as specified in the FSM. This caused an oil leak. *sigh*​

​

On a side note, the Febi bracket would not allow the pulley locking tool (round rod) to insert properly, the casting was not lined up with the hole in the flange. Since there are no name-brand brackets available via aftermarket, I shelled out for the OE bracket from the dealer. On the OE bracket, the pulley lock tool fits perfectly! After cleaning everything and installing with the proper sealant on the bolts, the leak is gone.​

​

Anyway - long story short - beware Febi parts, unless they are reboxing OEM stuff (like their reboxed SGF flex discs, which are fine).​

 

[Seangbadee]

If the bearing in the fan support bracket is bad, replace the entire assembly... besides, yours is damaged, the edge of the notch for the lock tool is broken off. Only buy the OE/dealer bracket. Photos here:
http://www.w124performance.com/images/M104_stuff/fan_bracket_OE_104-200-13-28/

Note one of the the bolts require using anaerobic sealant on the threads, or you will have an oil leak. I used sealant on all the bolts just to be safe. This is often missed in the FSM procedure:
http://www.w124-zone.com/downloads/MB CD/W124/w124CD1/Program/Engine/104/20-3140.pdf

Here's my sob story from summer 2014 on this particular job. Photos of the failed bracket are at this link. Febi is now very high on my naughty list, btw.

Febi is rapidly moving up my naughty list. View attachment 94232​

​

My new-to-me S124 wagon had a record of the M104 fan bearing bracket being replaced by a shop a few years ago. The receipt shows the shop charged the previous owner full MB dealer retail at the time for the bracket ($278)... but they installed a Febi bracket instead. The Febi bracket failed in 4 years / 38kmi, the bearing was loose in the casting and allowed the pulley to move forward/aft 2-3mm. View attachment 94233​

​

The Febi bracket was made in Germany, btw... no Chinese stuff here. Apparently Febi can't even make quality stuff in Germany! It is also sad that a shop would charge a customer dealer retail, and then install a part which they probably paid 1/3 as much for. As a bonus, the shop did not install it correctly, they did not use anaerobic sealant on the bolts during installation as specified in the FSM. This caused an oil leak. *sigh*​

​

On a side note, the Febi bracket would not allow the pulley locking tool (round rod) to insert properly, the casting was not lined up with the hole in the flange. Since there are no name-brand brackets available via aftermarket, I shelled out for the OE bracket from the dealer. On the OE bracket, the pulley lock tool fits perfectly! After cleaning everything and installing with the proper sealant on the bolts, the leak is gone.​

​

Anyway - long story short - beware Febi parts, unless they are reboxing OEM stuff (like their reboxed SGF flex discs, which are fine).​

View attachment 94231

Well, thanks for sharing that information about febi parts. I was under the impression that they would be heads and shoulders above Uro, but it seems they ride in the same boat.
I just noticed the crack in the slot for the locking tool.
I'll have to shell out about 200 for the part. Phew!!!
Which anaerobic sealant would you recommend?
Thanks for the heads up on that. I missed it on my 1991 300E which started leaking oil from one of the bolts , after I coupled the bracket back.

 

[gsxr]

Which anaerobic sealant would you recommend?

Any anaerobic sealant should be fine. The MB stuff is expensive. There's an Elring equivalent that costs less. Might be something from your FLAPS/McParts in another brand like Permatex if you need it quicker.

 

[notPatrick]

Not to sound too desperate, but would anyone be willing to sell me their homemade 8mm socket and spinner? My fan shroud was incorrectly installed (just barely) causing the fan to scrape and then promptly one of the fan blades snapped. Now Im stuck in the desert heat of Phoenix, AZ with no car (or garage) and no real tools to fabricate myself a kit...

Will pay with money... or my soul...

 

[gsxr]

notPatrick, in your photo it appears the face of the clutch (plastic portion) is closer to the radiator than normal. Might be an optical illusion, hard to tell. Can you measure the air gap? If it's less than ~20mm, it will be almost impossible to get any tools in there, and you will have to pull the radiator to get access to the clutch. Normal air gap is in the 22-26mm range.

Why would yours be lower, you ask? Because the 400E/E420 has a different lower radiator support than E500E, and the .034 lower support bar has almost always kissed a concrete parking curb, pushing the bottom of the radiator inward. As Klink would say, I've seen it a million times...

EDIT: See the photos in post #2 of this thread. I use the 8mm cut-down Allen wrench to remove the bolt. There is no room for any sockets with the radiator in place. You have to remove the upper shroud (or push it back towards the engine), get the Allen wench in the bolt, then use ChannelLock type pliers on the end of the Allen wrench. And then hope the last guy didn't gorilla the bolt in place.

 

[darek_u]

So long my Hella Behr visco clutch... Made in Germany... Top quality... Reputable brand... After 8 months it is gone. It lost all oil or at least enough to prevent from engaging. Bimetal strip works as expected, it is just the oil that I found all over the clutch and fan. Anyway, I was lucky to buy reboxed BorgWarner clutch (ACM in US?) for around $60, in FEBI box, brand new, sale item. I put it in place and everything works as expected again. A little comparison - M119 BorgWarner clutch is louder than Hella M104, in general M104 Hella clutch and ML plastic fan are quieter and "softer" than OEM combo.

 

[LWB250]

Did you consider refilling it? Granted, there must be some reason it leaked out, but you can refill the clutches.

Dan

 

[gsxr]

Refilling OE/OEM may be worth a try in some cases, but the silicone may keep leaking... depends how bad the leak is.

Not sure the ROI is there for refilling aftermarket, and/or if the leak is significant (i.e., seal blowout vs slow small leak).

That's one thing I like about large OE M119 (Sachs/Horton) clutches used on all W140, R129, and W124. They do not leak silicone if kept vertical. Totally different design than the skinny clutches.

 

[darek_u]

Did you consider refilling it? Granted, there must be some reason it leaked out, but you can refill the clutches.

I do consider refilling, I think it is worth a try. It didn't develop a massive leak, at least I cannot see any obvious damages etc. It just slowly lost the oil, not sure where from, the whole thing was covered with thin oil film. I read that people used a Toyota silicone oil with success, I'll try to source a bottle.

 

[LWB250]

I do consider refilling, I think it is worth a try. It didn't develop a massive leak, at least I cannot see any obvious damages etc. It just slowly lost the oil, not sure where from, the whole thing was covered with thin oil film. I read that people used a Toyota silicone oil with success, I'll try to source a bottle.

The oil, despite it being like 10,000 weight, can still slip by the pin under the bimetallic strip if the bore isn't tight. I have successfully refilled fan clutches for other models using oil for radio controlled truck differentials like this:

OFNA 10235, 10,000wt Silicone Differential Oil - NitroHouse.com

It takes a little while to do it, but it works. For the time and $USD 5 I'll give it a try.

Dan

 

[Jlaa]

The oil, despite it being like 10,000 weight, .......

OFNA 10235, 10,000wt Silicone Differential Oil - NitroHouse.com

That 10,000 wt isn't a joke or hyperbole ..... it is really a thing!!!!
That means that the legendary 10000SEL MUST. BE. REAL.

 

[LWB250]

That 10,000 wt isn't a joke or hyperbole ..... it is really a thing!!!!
That means that the legendary 10000SEL MUST. BE. REAL.

Yup. Got a partial bottle of it on the shelf in the garage. Knock it over tonight and maybe by tomorrow some might start dripping out. Maybe.

Dan

 

[gsxr]

It's been ~15 years since I did this (on an M103, or OM603 clutch) but I recall it being time-intensive. Like a couple of hours. AND, be careful not to over-fill. If you put too much in, clutch may be "always engaged", which isn't great either.

YMMV, etc.

 

[LWB250]

It's been ~15 years since I did this (on an M103, or OM603 clutch) but I recall it being time-intensive. Like a couple of hours. AND, be careful not to over-fill. If you put too much in, clutch may be "always engaged", which isn't great either.

YMMV, etc.

True. I've done it in the past as more of a challenge than a repair.

Dan

 

[darek_u]

Dan did you drill a new filling hole or remove the bimetallic strip and use the pin (piston?) hole for refilling?

 

[LWB250]

Dan did you drill a new filling hole or remove the bimetallic strip and use the pin (piston?) hole for refilling?

I used the pin/piston hole for refilling. The pin lifts right out once the bimetallic spring is removed.

Dan

 

[darek_u]

I had a quick look and I can easily purchase a silicone oil weight 10000cSt. Is it the same as 10000wt? Any ideas?

 

[gsxr]

There are a few different weights available. I think you can probably source between 6,000 and 12,000 cSt. 10,000 cSt should be fine.

Found some of my old notes from 2006:

My 300E has been running too hot in summertime, especially in slow​

stop & go conditions. I verified that the electric fan was working​

properly, and yes, it kicks on high speed when coolant temps exceed​

105°C, as it should (thanks to a new switch - the old one wasn't​

kicking the fan on.) But, the electric fan isn't enough to cool the​

engine by itself, it's only there to help the main fan. With the​

engine temps at 110°C, I killed the engine, and the fan kept spinning​

for several seconds... it was definitely not coupled. Radiator fins​

are clean and there was no cold spot in front of the clutch. Looked​

like a good candidate for the silicone refill theory.​

​

​

The Surgery:​

I pulled out that half-liter bottle of 12,000 cst silicone fluid which​

I purchased a while back (from someone who bought a gallon of the​

stuff, and was re-selling smaller quantities.) The bi-metallic strip​

(BMS) is simple to pop out on the M103 clutch, it's more glued in​

place than mechanically locked in, believe it or not (unlike the OM60x​

clutches I've seen.) With that out, I used the previously mentioned​

method of heating the clutch, and slowly dripping in the fluid as the​

clutch cooled. I'm not sure how much I ended up putting in, as I​

didn't measure the quantity. I lightly clamped the back side of the​

bearing in a vise, so I could spin the fan. Before I started it spun​

easily with no resistance. I stopped filling when I noticed a decent​

increase in resistance. I glued the BMS back in place with a dab of​

RTV at each end, same as it was originally.​

​

​

Results:​

Well... good & bad, I suppose. First the bad. When cold, the clutch is​

fully coupled, and doesn't appear to de-couple after a few seconds (as​

a normal clutch would). The good news is, when warmed up (after a​

20-minute test drive), the clutch does de-couple, and appears to​

operate normally. I let the car idle (in 100F ambients, with the AC on​

max) long enough to get the engine temp to about 100C, and around that​

point, the clutch coupled as you would expect (due to the BMS​

expanding). Now, I couldn't find anything in the M103 service manual​

about temperatures or engine RPM's, but when hot & coupled, the clutch​

stayed coupled up to at least 4000rpm... it finally appeared to back​

off above that speed (I think the OM603 clutch is supposed to stay​

coupled up to 3500rpm when the BMS is triggered.) Hot or cold, the fan​

now stops very quickly when the engine is shut off. It's not instant,​

but I'd say it stops within a half-turn. Oh yeah - so how does it​

cool? MUCH better... so far, I haven't seen the temps over 100°C yet.​

I'll keep an eye on that though. Remember, this was compared to an​

old, shot clutch that was probably just floating along at idle speed​

all the time. I was trying to avoid plunking down ~$175 for a new fan​

& clutch.​

 

[darek_u]

Great info! Thank you Dave.

 

[nic520]

Yesterday while standing in a traffic, the original visco decided to kill the radiator. The bimetal came off, I guess. I do not know why.

So long my Hella Behr [M104] visco clutch... Made in Germany... Top quality... Reputable brand... After 8 months it is gone. It lost all oil or at least enough to prevent from engaging. Bimetal strip works as expected, it is just the oil that I found all over the clutch and fan. Anyway, I was lucky to buy reboxed BorgWarner clutch (ACM in US?) for around $60, in FEBI box, brand new, sale item. I put it in place and everything works as expected again. A little comparison - M119 BorgWarner clutch is louder than Hella M104, in general M104 Hella clutch and ML plastic fan are quieter and "softer" than OEM combo.

Sorry to hear the M104 clutch did not last - that was my solution for now…
Nic

 

[gsxr]

Yesterday while standing in a traffic, the original visco decided to kill the radiator. The bimetal came off, I guess. I do not know why.

That is scary. I don't think I've seen a Sachs clutch where the spring has popped out unprovoked. It can happen if the bracket has been tweaked or bent outward, which usually wouldn't occur unless someone was trying to adjust the engagement point and over-corrected. Really bizarre.

Sorry to hear the M104 clutch did not last - that was my solution for now…
Nic

All the 4/5/6 cylinder "thin" clutches, Behr or Sachs, are known for losing silicone fluid over time. But it's generally many years, not 8 months. They can be re-filled if the bearing is good, but it's a PITA as described in post #445 above. It's depressing that a Behr Germany failed in a short time. I don't know if Sachs Germany would be any better or not. On the M10x and OM60x engines, these thin clutches need replacement far more frequently than they should, due to the fluid leaking.

By comparison, the M119 OE Sachs/Horton clutches almost never, ever leak fluid OR have bearing failures. It's a very robust design. The main issue is they are mis-calibrated, even brand new from the factory, as discussed earlier in this thread.

 

[nic520]

While searching for alternatives, I have come around two stories of this happening to E420/E500 with original clutch in Germany. Mayby it is a matter of time at higher rpm, which lets the old holding arm bend outwards by centrifugal force. The rest of the clutch is ok and could be reused…

 

[gsxr]

While searching for alternatives, I have come around two stories of this happening to E420/E500 with original clutch in Germany. Mayby it is a matter of time at higher rpm, which lets the old holding arm bend outwards by centrifugal force. The rest of the clutch is ok and could be reused…

The holding arm shouldn't move, but I can't think of any other explanation. With the bimetal spring removed, the clutch would be fully engaged at all times. However you'd need to find a way to hold the pin in place so it cannot fall out, as it would allow the fluid to leak if the pin is removed. AFAIK it's not possible to repair or replace the bracket, swapping from a different (140/129) clutch for example.