Viscous Fan Clutch Replacement

[gsxr]

Alright, I am ready to do my Viscous Clutch. I have read this whole thread, and I am more or less fine with buying the OEM one (even though it is more than 700 bucks!) if it is better or correct. I am also happy to run the ACM one. I see that some of those aren't as good now, etc etc.

What's the current belief? Is the OEM one better in some way? Or just a plain old waste of money?

Also, should I replace the fan blades as well? If so, what's the Part number there?

Or just reuse?

Dan, I believe the OEM Sachs/Horton is a better unit overall. The bearings seem to last almost forever and they rarely if ever leak fluid. There has been discussion in the past that even brand new ones from the dealer may not engage at the correct/desired temps; Klink mentioned having to go through a half-dozen new ones to get one that worked how they wanted (back when these cars were under warranty at the dealer, IIRC). The problem here is that testing a new clutch is not easy, you need a warm day and engine temps high enough to know the clutch should be engaged. If you don't have a reference point, it's hard to know if your new clutch is "good" or "bad" (more accurately, if it's engaging at the correct temp, or not). If the car is running under 100C and you can confirm the clutch is engaged at least some of the time, I'd leave it alone.

The Wiki should have more info, but for a quick check, run the AC on a warm day (90°F or higher, if possible) and get engine temps to at least 90°C (or higher). See if the fan roars as you slowly increase engine RPM (car parked, driver door open, or window down, so you can hear better). The roar stops when the clutch disengages. It is not a binary on/off thing; it can be partially engaged and decouple at (for example) 2000rpm. When fully engaged, it will decouple very obviously at 3500rpm, and not re-couple until revs drop significantly (i.e., down to 1000rpm or so). If you can confirm the clutch is engaged / coupled, definitely don't replace it.

My complaint with the ACM is that it engages at a LOWER temp than OE and runs almost all the time; and it doesn't decouple until 4500rpm. Neither issue the end of the world. You need a different/shorter bolt to install the ACM. One minor advantage to the ACM is that it's easier to R&R because it's so much thinner. If you don't have the special tools to remove the OE clutch, you will need to pull the radiator (not fun).

 

[Dbreid]

Alright, I went ACM. I briefly thought about buying both, but I am low on time for research. Also bought the bolt and the special tool, and a couple of 8MM allens to cut down. The thinner clutch should make it so I don't have to pull the radiator (which I am fine with, I just like it to be faster).

 

[gerryvz]

Dan, I believe the OEM Sachs/Horton is a better unit overall. The bearings seem to last almost forever and they rarely if ever leak fluid. There has been discussion in the past that even brand new ones from the dealer may not engage at the correct/desired temps; Klink mentioned having to go through a half-dozen new ones to get one that worked how they wanted (back when these cars were under warranty at the dealer, IIRC). The problem here is that testing a new clutch is not easy, you need a warm day and engine temps high enough to know the clutch should be engaged. If you don't have a reference point, it's hard to know if your new clutch is "good" or "bad" (more accurately, if it's engaging at the correct temp, or not). If the car is running under 100C and you can confirm the clutch is engaged at least some of the time, I'd leave it alone.

The Wiki should have more info, but for a quick check, run the AC on a warm day (90°F or higher, if possible) and get engine temps to at least 90°C (or higher). See if the fan roars as you slowly increase engine RPM (car parked, driver door open, or window down, so you can hear better). The roar stops when the clutch disengages. It is not a binary on/off thing; it can be partially engaged and decouple at (for example) 2000rpm. When fully engaged, it will decouple very obviously at 3500rpm, and not re-couple until revs drop significantly (i.e., down to 1000rpm or so). If you can confirm the clutch is engaged / coupled, definitely don't replace it.

My complaint with the ACM is that it engages at a LOWER temp than OE and runs almost all the time; and it doesn't decouple until 4500rpm. Neither issue the end of the world. You need a different/shorter bolt to install the ACM. One minor advantage to the ACM is that it's easier to R&R because it's so much thinner. If you don't have the special tools to remove the OE clutch, you will need to pull the radiator (not fun).

+1. A new clutch is a once-every-15-years repair, and factory is best if one is serious about maintaining their car to a high standard. I believe, and this has been somewhat corroborated by Klink and GSXR, that most all original Sachs clutches for the .036 were defective from the get-go and have NEVER worked right. And I believe that the current Sachs/Horton factory MB clutches have been fixed and work much better, as originally intended.

I recently installed an original OE MB clutch from a 1992 500E that had 50,000 miles on the clutch/engine. And I've driven it all summer here in the Houston heat/humidity.

While the 50K mile original clutch performs somewhat better than my original clutch (i.e. I never see temps get above 105C in the nastiest heat, with the A/C blasting), it is my believe that a properly operating clutch would never EVER allow temps to get above 95-100C indicated unless sitting for a long long traffic light or otherwise not moving.

Original clutches that I've replaced on my M104 and M117 keep these engines at or below 95C temps even in the worst Houston summer heat.

Cheers,
Gerry

 

[gsxr]

+1. A new clutch is a once-every-15-years repair, and factory is best if one is serious about maintaining their car to a high standard. I believe, and this has been somewhat corroborated by Klink and GSXR, that most all original Sachs clutches for the .036 were defective from the get-go and have NEVER worked right. And I believe that the current Sachs/Horton factory MB clutches have been fixed and work much better, as originally intended.

To clarify... my experience has been that the original clutches generally were OK, but two new OEM Sachs were "bad" out of the box (meaning I had to tweak them to make them work right). Klink had a similar experience with new replacement clutches. I'm not sure what Klink's thoughts are on how many cars/engines were built with clutches that were "bad" (engaging at too high a temp). Klink?

 

[Dbreid]

Update. I will be slower than I thought replacing this thing, because the holding tool is gonna take 3-5 weeks to get here. I'll update when it arrives.

 

[samiam44]

To clarify,

Currently the Fan clutches are made by Horton. Horton makes all the big rig clutches, but their quality might be a bit varied. I put a new Horton clutch and OE rebuilt water pump on ?last year and my car is running much cooler.



Michael

 

[Klink]

To clarify... my experience has been that the original clutches generally were OK, but two new OEM Sachs were "bad" out of the box (meaning I had to tweak them to make them work right). Klink had a similar experience with new replacement clutches. I'm not sure what Klink's thoughts are on how many cars/engines were built with clutches that were "bad" (engaging at too high a temp). Klink?

My experience as a dealer technician in Central Florida during the entire time the cars with M119 engines were in production was that most of them had a fan clutch that for all practical purposes did not work at all. And when I say "did not work", I mean that they did not even engage before the auxiliary fans were switched on high-speed in a desperate effort to cool things off while that gigantic engine fan just sat there freewheeling. If I disabled the auxiliary fan as an experiment to see if they would engage it all, they did at around 105-110 degrees. This was also true, but mercifully on fewer vehicles for cars with the M120.

And yes, you could receive three or four new ones that were just as bad, but usually by the second replacement of the replacement we had one that worked acceptably. IIRC, they were all the F&S (Fichtel & Sachs) or Sachs brand. Note, that's the same brand, just later on they did the ole "Roebuck" on Fichtel...


Years later, it seemed that most of them were shipped correctly adjusted. I think Sachs saw what happened to Fichtel and cleaned up his act some.

My experience with all of the Horton branded dealer sourced clutches on all the models on which I have seen them installed has been excellent.

 

[Dbreid]

Update. I will be slower than I thought replacing this thing, because the holding tool is gonna take 3-5 weeks to get here. I'll update when it arrives.

Ok, I finally got around to doing this job last night. I bought the factory tool (that holds the pulley) and it was stellar. I cut down an 8 mm Allen and it went well. My only issue was that I couldn't get the stupid fan shroud out until I pulled the fan blades. The captive speed nut had "spun" and I couldn't get that bolt out.

So I pulled the shroud intact and replaced the bolts not he bench.

Then it was easy.

Hasn't been hot today, but the car seems to still run perfectly fine so far. Another report when I need AC on a hot day.

I saved the factory clutch if someone needs it for science.

 

[jhodg5ck]

Ok, I finally got around to doing this job last night. I bought the factory tool (that holds the pulley) and it was stellar. I cut down an 8 mm Allen and it went well. My only issue was that I couldn't get the stupid fan shroud out until I pulled the fan blades. The captive speed nut had "spun" and I couldn't get that bolt out.

So I pulled the shroud intact and replaced the bolts not he bench.

Then it was easy.

Hasn't been hot today, but the car seems to still run perfectly fine so far. Another report when I need AC on a hot day.

I saved the factory clutch if someone needs it for science.

I'm always looking for old spare clutches:-D

Sent from my XT1585 using Tapatalk

 

[Dbreid]

By the way (because I always love it when I read threads that have all the details), I bought this Allen key:

http://www.amazon.com/IceToolz-Alle...TF8&qid=1461609409&sr=8-1&keywords=8+mm+allen

And cut it down with a dremel tool with a cutoff attachment. One thing I would have changed would have been I would have made it much longer (the handle, not the part that I cut). But this was a very workable solution. I also liked that it had a little foam handle and stuff, because it saves the radiator from getting dented.

Overall worked well.

 

[gsxr]

Dan, just curious, was the original fan clutch not engaging when hot? Or was this just a proactive replacement?

Nice find on the long-handled 8mm Allen, btw! Might need to snag one of those for my 589 collection...

 

[gerryvz]

my 589 collection...

A lot of work to do, bolstering your 589 and 989 collections.

 

[tomer]

Hi, I need to do this job soon also!

To confirm, the factory tool to hold the pulley is used on the water pump pulley? Not on the fan clutch in any way?

Also, has anyone been able to use a bar/long screw driver to connect with two bolts on water pump pulley? Perhaps a small square bar?

thx
Tomer

 

[gerryvz]

The factory tool does not touch the fan clutch; it holds the water pump fan pulley.

See attached factory doc/diagram.

Although the "shortened" hex key is a nice short-cut, even with it, it's a VERY tight fit and working space. Removing the radiator, while a bit messy/PITA, is worth IMHO the extra 30 minutes of labour, and you won't ding up the backside of the radiator.

Note also that replacing the radiator also gives you the opportunity to replace about a gallon-plus of the engine's coolant, which is the amount that will leak out when you drain the radiator. That's about 35+% of the coolant capacity of the entire cooling system.

 

[gsxr]

Uh, actually, the water pump pulley is not the same as the fan/clutch pulley. The fan/clutch mounts on a separate bracket which routes coolant through the middle, but is completely separate from the water pump.

In photo below... water pump is directly above crank pulley. Fan clutch mounts to the left, next to the air/smog pump

 

[gerryvz]

You're right, my bad. It's the fan pulley not the water pump pulley. I was giving the factory diagram a quick look and didn't stop to think about the pulley positions.

Edited my post above.

 

[Dbreid]

Dan, just curious, was the original fan clutch not engaging when hot? Or was this just a proactive replacement?

Nice find on the long-handled 8mm Allen, btw! Might need to snag one of those for my 589 collection...

Well, to be honest, I am not really sure if it wasn't engaging. It doesn't usually get all that hot here where I live in CA, and I am not often sitting in traffic with the AC on. Last summer there was one hot day where that happened (hot, sitting on highway, AC blasting), and I noticed the car getting hotter (above 100). So I revved the engine, and it din't seem to kick on and ROAR. So I assumed it wasn't really working correctly. Then I just decided to replace it, so that this year, when there's those three freak days, it will stay cool.

 

[Dbreid]

I'm always looking for old spare clutches:-D

I mailed mine to you the other day. You should see it shortly.

 

[tomer]

Well, thanks to "Dan the Man" Dbreid, who loaned me his special tools, I managed to replace my fan clutch on Sunday... It was shaping up to be the best fathers day ever, as my 13 year old daughter was helping her Daddy... She held the tool on the fan pulley

Just my luck, the new fan clutch is clutchless too!!! Darn thing does NOT lock up... After calming down a little, I realize I need to really check the rad/AC coil for possible obstruction, but just can't believe this would be the case, and with the aux fans in place, will I be able to see?

This might be where Gerry jumps in and calls my laziness, perhaps I should R&R the rad then I can get a first hand view if there is any "crud" between the rad and AC condensor?

Lastly, with the new OE Horton clutch, now when at operating temp, actually right between the 80 and 100 degree mark, when I rev the engine, I hear a distinct "click" which sounds like a relay, but of course I can't locate the source of the sound... Is the unit supposed to make a "click" sound when it engages (or tries to engage in my case) as I rev the engine?

For anyone doing this job with rad in place, I made the worlds cheapest tool to be able to loosen the bolt the last two turns, as at this point the cut down allen key is going to rub the fins on the radiator... I found a bolt with an 8mm head (what luck... I don't have many metric fasteners laying around) and bolted it to a (get ready for it....) Kelly Moore paint stir stick, then cut the bolt of the other side flush with the nut, and voila, a simple way to loosen the main bolt the last couple turns as your hand won't fit between the clutch and rad... Also works well to thread the bolt back in, far enough to where you can use the cut down allen key tool...

I also used a sheet of thin plastic up against the rad fins for the entire procedure, to prevent damage... I think what I used was a thin craft cutting pad that my son had for and exacto knife...

If it weren't for bad luck, I would have no luck at all!!!

Tomer

 

[tomer]

Hey, I got 2 likes... Perhaps in a small way I can claim I contributed versus always receiving from this awesome forum!!

I am happy to post a pic of my special tool - makes me laugh just thinking about it... I put the 8mm bolt right in the middle of the paint stir stick, so it is like a propeller when attached to the bolt, but very easy to spin that way...

Tomer

 

[gsxr]

Hi Tomer,

There should not be any particular "click" noise related to the viscous fan clutch. It should be a smooth transition between engagement and disenagement. If the AC was on, you may have been hearing the compressor clicking on/off.

Remember, the fan clutch does not engage based on engine coolant temp! It is based on air temp at the face of the clutch. Usually when engine temps are ~100C the clutch should be engaged, particularly if AC is on and in warm ambient temps (say, over 85-90F). If it's cool outside and/or the AC is off, the clutch may not engage. All of this is why fan clutch testing is a royal PITA, and it cannot be done at all in cool ambient temps.

As you noted, an important item is to check for obstruction of both radiator & condenser fins directly in front of the clutch; and also confirming the radiator is hot to the touch in front of the clutch (i.e., no flow issues internally).

If you aren't seeing engine temps over ~100C, I wouldn't lose too much sleep over it...

 

[nocfn]

There is no doubt audibly when the fan begins to run, sounds like a outboard motor just took off behind the radiator.


Best part of your story was your little helper....

 

[tomer]

I have a 99 BMW 528i, and I even tortured my kids explaining how a fan clutch was supposed to work, and how the electric fan is primarily back up for when engine is idling...

Although the requirements are no doubt different, yesterday with ambient temps around 85 degrees, and driving my beemer with AC on around town, there is no doubt that fan clutch was locked up and as noted, with hood open, standing and reaching in to rev engine just a couple thousand rpms, the air flow from that fan is like a small hurricane!! From my weird position with left foot on ground, right foot reaching in to push gas pedal, the air wafting thru the space between the open hood and windshield is very noticeable!!

Wish my E500 could have some of that action!!

 

[tomer]

Quick update on my saga... Stopped at my trusty mechanics shop last night after work... THey have been in business for 31 years, and they are trust worthy. For free they checked the temps of the radiator with their temp gun, and determined the temps across the rad were even and they do not suspect any internal flow issues from the rad... The upper radiator hose was hotter than the lower, and they said that is expected since coolant flows into the top of the rad and is pumped back into the engine at the bottom of rad...

The owner is not very suspicious that the new fan clutch is faulty... Although with ambient temp around 85 degrees F, and car idling with AC on, the fan clutch would not lock up, but the aux fans would come on to cool her down... Temp would not quite reach 100 before aux fans come on... Owner "suspects" that if temps were to go up near the red mark - say I was in 100 degree + temps, idling, AC on, etc... then the fan clutch would engage... He also while car was idling with aux fans running, held a rag in his hand and was able to easily stop the fan from rotating.... Of course he was careful to insert his rag/hand in the correct direction...

So, his conclusion is, if I am not seeing temps over 100, he would not worry about it... I believe gsxr says same thing... If I lived in area which gets 100 degree heat I would be able to easily run the temp up and see if fan clutch engages, and that might require some planning because if fan clutch does not engage, I would perhaps have to stop and turn car off and let her cool down before proceeding...

Would appreciate opinions on what I should do... Should I get another clutch from MBZ and try it? Or, just roll as I am...waiting for some opportunity where temps are higher and perhaps I am going up some big hills, then temps will go up and I can do a more thorough test...

Frustrating... I like the fact that my clutch fan on my bmw e39 will engage when temps are hot and AC is on...

Tomer..

 

[gsxr]

This is a tough subject because the word "hot" means different things to different people. Some folks expect (or at least want) their engine to run right around 85C all the time. Others are happy as long as temps remain between 80-100C. At the other extreme, I was personally told by a dealership in the late 90's that since the needle wasn't in the red, the 115C engine temps I was experiencing on my 87 300D were 'normal' and nothing to be concerned about. I've heard similar reports from other dealers. (On my 300D, a new radiator fixed the problem, and proved the dealer wrong.)

Anyway - the 124.036 E500E (and 124.034, 400E/E420) should be in the 80-100C range most of the time. If fully warmed up and still below 80C, either the t-stat is bad or the gauge is inaccurate. Above 100C things get complicated. If conditions are extreme enough, temps at 110-115C for brief periods may be normal. But we're talking Death Valley or climbing insane grades in brutal heat with 4 occupants and luggage with AC full blast, not idling around San Francisco in springtime. In general, if temps go above 105C, there is a good chance something is wrong. The electric fans trigger on high speed at ~107C.

As Klink has mentioned previously, the OEM Sachs/Horton clutches seem to be very hit or miss on engagement temps, even brand new. I have absolutely no explanation for this. Remember these are analog devices, not digital. They can be partially engaged, in which case the clutch will be coupled but will disengage at a lower RPM than the max-speed cutoff (3500 engine rpm). So, if the fan roars to say 1500 or 2000rpm, then goes quiet above that point, it was partially engaged. If it roars to 3500rpm, it is fully enagaged.

Does the mechanical fan NEED to be engaged at 90-100C? Probably not, but a 'good' clutch may enagage around those engine temps, depending on ambient air temp and AC condenser heat levels. I don't mind if the fan isn't engaged at 90-95C because there is less noise, more power, better MPG, and minimal advantage to having it engaged. I personally like to see it fully engaged at or above 100C in summer.


Tomer, sorry for the long ramble, but if I'm reading your post correctly, your engine is not exceeding 100C. If that is the case, I wouldn't worry about it. Chances are pretty high that another new OE clutch may act the same as your current one. You could always make a day trip to Sacramento area and see how it behaves up there in 110F ambients. Keep in mind the "partial engagement" thing. Stick to the audible roar test, don't insert rag/hand into the fan at any speed - this isn't a viable test of anything besides how well your fingers remain attached to your hand.

 

[nocfn]

Oh my on the rag test. May seem silly to ask, but what is the condition of the resistor and associated wiring at the left headlight area? Fans come on so it must be working, but worth changing out.

 

[tomer]

Thanks so much for the prospective Dave!!!

I agree with all your points!! As soon as I get a chance to drive in some hills with ambient tem[s ~ 90, with AC on, I will do so...

The part that bugs me most is the new clutch DOES NOT produce the audible roar when cold and on start up... Most agree it should produce the roar on cold start up for a couple seconds... Mine will not...

Being a sucker for punishment, I will try another clutch from MBZ, and advise the team!!

Tomer

 

[tomer]

I will inspect this, but yes, the fans do work just fine, which is what keeps her cool... Right now, with no apparent lock up of the clutch fan, it serves no purpose (not withstanding the fact that I may not have yet experienced high enough air temps to engage it... But I am betting $20 that it is defective!!!

Oh my on the rag test. May seem silly to ask, but what is the condition of the resistor and associated wiring at the left headlight area? Fans come on so it must be working, but worth changing out.

 

[nocfn]

I replaced my fan on the c126 and all my dreams can true

 

[gsxr]

I replaced my fan on the c126 and all my dreams can true

LOL. You need to dream bigger!

 

[nocfn]

Hehehehehe

 

[8899]

Although with ambient temp around 85 degrees F, and car idling with AC on, the fan clutch would not lock up, but the aux fans would come on to cool her down...

In that scenario I would fully the expect the fan clutch to be engaged. With a properly functioning fan clutch, you should only rarely have the aux fans turn on...when temps are at around 100*C.

 

[8899]

The part that bugs me most is the new clutch DOES NOT produce the audible roar when cold and on start up... Most agree it should produce the roar on cold start up for a couple seconds... Mine will not...

Yes, that is problematic.

 

[gsxr]

Keep in mind the auxiliary fans trigger on low speed based on refrigerant pressure: on at 16 bar, off at 12 bar. At lower ambient temps, the refrigerant pressure may not be high enough to engage the electric fans. At higher ambients, they typically turn on within ~10 seconds of the compressor engaging. 85F is kinda in the middle; hard to say if/when the fans would run on low speed (also varies with charge level, if a bit low they are less likely to turn on).

But anyway - yes, 100C engine temps at 85F ambients with A/C running, I'd expect the mechanical clutch to at least be partially engaged (i.e., engaged at idle and lower RPM, although it may disengage somewhere between 1k-2k rpm). It helps that I have five different cars with the same engine/clutch setup to compare - and I've experimented with different clutches as well!

Side note: I am not positive if there is always a "cold startup roar". I will try to monitor that. Klink? Where art thou?

 

[vatc5637]

Just a quick note, was shopping today for fan clutches, ACM @ AutohausAZ - $84.37 (was $140 4 years ago when I bought one for the E420); MB OEM Sachs @ mboemparts.com - $654.90. A/C resistor (pn 0001583245) $23.04. For those of us who are "overheated".

 

[TerryA]

I just bought the ACM clutch from AZAutohaus. Not installed yet. Maybe this weekend.

 

[gsxr]

Don't forget you need a shorter bolt for the ACM clutch! Should be documented earlier in this thread. If you don't want the old OE clutch, drop me a line...

 

[JC220]

Re: Vicous Fan Clutch Replacement

Did anyone have any experience with the BERU unit - I want to get one as a spare and BERU is a pretty good Company; they make all the ignition system parts we use on a day to day basis........
Paul

Just for those curious about the Beru Fan clutch – here are pics of a new one I just bought. I think my original viscous clutch was kaput (Stuck full on) although I did not test it before removing.
Still waiting on this new Beru item to turn up so I can take a closer look on where it was made etc. Seller says Germany but he might just be reading the Beru Box.

Some of you will know I have converted my 500E to electric fans. This is a backup plan to have on the garage shelf should I decide to convert back in the future for whatever reason. I did do the electric fan install so it can be removed without any trace in about 15 minutes. I am still getting used to the fan switch kicking in & out so the jury’s out if I am 100% convinced I like the electric fan setup. Both fan systems have their pro’s & cons really-

Viscous Coupling –
High amount of CFM Air flow
Saps HP since it’s mechanically driven
Engaged whilst moving until high RPMS – where it may not otherwise be needed.
Following both points above - Increased Fuel Consumption
Fan Noise at highway speed is quite high

Electric Fans -
No mechanical drag on the engine – maybe saves 5 – 8hp?
Fans run about 70 - 100% of the time at idle depending on ambient temps
Not engaged at all when the car is moving – fuel savings
When the fans are active they cannot be heard inside the car – but they are noticeable outside
Noticeable decrease in overall noise when driving the car at highway speeds.

This is the spec + X Ref numbers for the Beru clutch-

https://www.123spareparts.co.uk/car...!!g!!&ef_id=VOi0RAAABV9a1iOq:20161103185928:s
This spare fan clutch was my fleabay bargain find of the year. £25 inc shipping (From a private seller who had it spare / surplus)

For storing this viscous clutch long term should I keep it in a vertical orientation? I have read that oil can weap out of the seals if left lying on it's flat.

 

[gsxr]

Beru and Borg-Warner do not make these clutches. It appears to be a reboxed ACM or Vemo (hard to say which). Remember that it needs a shorter bolt than the OE clutch, as described on the first page of this thread. Interesting to note there is no country of origin marked on the clutch, box, or label...

 

[JC220]

Beru and Borg-Warner do not make these clutches. It appears to be a reboxed ACM or Vemo (hard to say which). Remember that it needs a shorter bolt than the OE clutch, as described on the first page of this thread. Interesting to note there is no country of origin marked on the clutch, box, or label...

Yes it's strange that it doesnt say 'made in ....' anywhere. I'll take acloser look when it turns up. Yes I agree from the pics it looks like ACM or Vemo

 

[Klink]

Keep in mind the auxiliary fans trigger on low speed based on refrigerant pressure: on at 16 bar, off at 12 bar. At lower ambient temps, the refrigerant pressure may not be high enough to engage the electric fans. At higher ambients, they typically turn on within ~10 seconds of the compressor engaging. 85F is kinda in the middle; hard to say if/when the fans would run on low speed (also varies with charge level, if a bit low they are less likely to turn on).

But anyway - yes, 100C engine temps at 85F ambients with A/C running, I'd expect the mechanical clutch to at least be partially engaged (i.e., engaged at idle and lower RPM, although it may disengage somewhere between 1k-2k rpm). It helps that I have five different cars with the same engine/clutch setup to compare - and I've experimented with different clutches as well!

Side note: I am not positive if there is always a "cold startup roar". I will try to monitor that. Klink? Where art thou?

Oh, man. Busy as balls. Yes, start up roar is very common, and usually at least indicates that the clutch has a nice full charge of silicone oil. The centrifugal force spins the oil out of the work chamber shortly after start up. Opening of the valve via the bimetallic strip allows the fluid to migrate back into the work chamber and engage the clutch. That is not to say that a clutch that has no start up roar is definitely defective. Not every clutch experiences oil creep back into the work chamber when it is shut off...

 

[8899]

Re: Vicous Fan Clutch Replacement

High amount of CFM Air flow

I know, silly question, but what does CFM stand for?

 

[JC220]

Re: Vicous Fan Clutch Replacement

I know, silly question, but what does CFM stand for?

Cubic Feet per Minute. It's a measure of air flow. The Viscous fan moves a lot of Air but it's impossible to measure how much. Whereas electric fans are rated with CFM figures which determines their performance

 

[tomer]

gsxr, if you would like my old OE clutch please drop me a PM... I tried to send you a PM just now but was not allowed... Tomer

 

[gsxr]

Thanks, Thomas! I just sent you a PM (should be fixed now).

Any update on your new clutch, btw?

 

[JC220]

The 'Beru' fan clutch arrived today. Looking at it closely it matches Daves pics of the ACM clutches. Inc the made in China Orange seal on the rear. For £25 shipped it's still a great deal. But don't be fooled folks- Beru clutches list for 3 - 4x times the price of ACM clutches. Beru are a re-boxer it seems.

 

[500ESpain]

After confirming almost 100% that my brand new Sachs clutch is defective, I've finally found the time to replace it. The reason I think it's defective is that I've never heard it engaging and I also can move it easily with one finger with the engine temperature over 100C. When it was installed I didn't hear it but I thought it was normal but I had the chance to drive a friend's E500 and it was definitely audible.

I've read this whole thread and I think I'll go for the ACM. I will fabricate the hex tool but for the pulley holder I don't have the welding equipment/skills to make it so I want to buy the tool. My problem is that when I do the search for the "M119 pulley holder" on ebay, I get too many options and I'm not sure which one will work for the 500E. So I'd appreciate if you could tell me exactly which one will do the job.

Thanks in advance.

 

[gsxr]

I will fabricate the hex tool but for the pulley holder I don't have the welding equipment/skills to make it so I want to buy the tool. My problem is that when I do the search for the "M119 pulley holder" on ebay, I get too many options and I'm not sure which one will work for the 500E. So I'd appreciate if you could tell me exactly which one will do the job.

See posts 230, 231, 295, and 299 earlier in this thread for info on the pulley holding tools.

 

[500ESpain]

Thanks! So I understand none of the spanner type work because they're too thick. Most of the search results show you the spanner like ones but I guess it's for later M119s.

 

[gsxr]

Thanks! So I understand none of the spanner type work because they're too thick. Most of the search results show you the spanner like ones but I guess it's for later M119s.

Exactly. The spanner types are for the M119.985 engines with the different fan clutch (as seen in post #99), or the M112/M113/etc.