Viscous Fan Clutch Replacement

[samiam44]

I do not think that's the proper way to do it.

If you have a new clutch, make sure it is engaging at 95-100F or send it back. If it is an older FC, I would suggest reading threads on Porsche FC's and adjusting the operation point. You can shorten the rod slightly( thousands make a difference) or carefully tweek the height of the bi-metallic strip. There is an art to it, and the down side to doing it wrong is losing a clutch and radiator =0(.

It will probably require R&R a few times to get it adjusted right. My OE one out of the box is in range, but may need to be adjusted to lower it a tad. Won't know till 100F weather hits again- maybe I can go visit Gerry and still do it!

Michael

 

[AMGTesTDriverNJ]

Re: 500E / E500 Parts Manufacturer Quality List

Who else makes a fan clutch besides ACM? Is it worth the extra scratch?

 

[gerryvz]

Re: 500E / E500 Parts Manufacturer Quality List

Who else makes a fan clutch besides ACM? Is it worth the extra scratch?

For the M119, you're basically limited to ACM, and OE MB, which is made by Sachs/Horton ($$$).

The two clutches are of different profile and although the ACM is a direct fit, it requires a shorter bolt, which must be the M10 x 50mm size.

I believe a few folks have been running the ACM clutches on their 119s with good results, so far. Given the price of the OE MB clutch, it seems from what folks are posting that an ACM would be a realistic alternative.

Installation is well documented on this site. It's a good opportunity to check out the condition of the serpentine belts and pulleys and change them out if needed.

Klink has posted a pretty well thought-out theory on the OE MB clutches, based on decades of observation and experience, that postulates that most if not all of the OE clutches that originally came on our cars were more or less defective right from the get-go, and never worked properly. And this is why nearly all of our cars have had hot running problems over the years, particularly in hot and humid climates such as the Southern USA, midwest and east coast in summertime. I am inclined to agree with him on this.

GSXR has tested the ACM and OE clutches, and they showed different engagement characteristics.

Cheers,
Gerry

 

[AMGTesTDriverNJ]

Re: 500E / E500 Parts Manufacturer Quality List

Thanks Gerry. I'm going to try out ACM clutch to start. What do you run in your car?

 

[gerryvz]

Re: 500E / E500 Parts Manufacturer Quality List

What do you run in your car?

I'm still running the original OE MB fan clutch that came on the car, but it's been worn out / not working for a number of years now. I have a spare OE MB M119 clutch (Sachs manufacture) with ~50K miles on it, that I am going to change into the car next spring when the weather heats back up here in Houston.

If that low-mileage factory clutch doesn't offer any improvement over my existing unit, I'll also probably order an ACM to see how it works.

The current price of a the factory Sachs/Horton units available today is so exorbitant, that economically it really only makes sense to buy an ACM if buying a new clutch. I am really interested to know, if anyone has purchased one of the factory clutches in the past couple of years, as to whether the design/effectiveness has been improved over the faulty "out of the box" design of the majority of the earlier clutches, so that the engines have the proper operating temperature characteristics.

A properly operating fan clutch makes a HUGE difference in engine temps. My G-wagen's stock clutch was bad, and it was regularly & routinely operating in the 105-120C range, even on moderately hot days. I replaced that M104 clutch with a new factory unit (thankfully it is reasonably priced due to being used on M103 and M104 engines, so higher sales volume) and I have only seen the engine temp rise over 100C one or two times all summer, even in humid, high-90s Houston temps with the A/C blazing.

Since we've had this cold snap here in Houston over the past few days, I had my E500 out yesterday and the ~50-55F ambient temps really allow the car to run much cooler, even with the defective clutch on my M119. That's why I never noticed the clutch was shot when I was living in Portland, OR (cooler temps year-round). Was only when I got to Houston that I saw how a bad clutch can affect operating temps....

Cheers,
Gerry

 

[samiam44]

Re: 500E / E500 Parts Manufacturer Quality List

It should be noted on the ACM, that it does not dissengage at the right rpm. Dave has documented this...


I run mine above 4000 rpm all the time and hence replaced my clutch. My clutch was working, but it was damaged- the bi-metallic holder was bent. My car has yet to see 95+ F weather this year- but it has never gotten over 90 C since my work.
I did replace the fan shroud which was extremely helpful. I R&R'd it quite a few time with all the different things I was servicing. It was easier to remove the upper half to remove the clutch.

While my water pump was not gushing, the drain showed some corrosion like it was leaking. Rebuilt OE pump I attribute to alot of the cool running. I know they go a long ways before catastrophic failure, but I think they maybe a contributor in those having cooling problems. If you go to the WP effort, replace the front seal. Pull the whole harmonic balancer/hub, then you can remove the balancer from the hub on the bench to ease installation. It comes apart easily with a dead blow. Mine was friggin' tight- insanely tight. Even after cleaning on re-installation, the bolts were required to seat it.


Michael

 

[clarkz71]

Re: 500E / E500 Parts Manufacturer Quality List

It should be noted on the ACM,
that it does not dissengage at the right rpm.
Dave has documented this...


I run mine above 4000 rpm all the time and hence replaced my clutch. My clutch was working, but it was damaged- the bi-metallic holder was bent. My car has yet to see 95+ F weather this year- but it has never gotten over 90 C since my work.
. Michael

That depends on a few factors. I've documented correct operation with the ACM

Mine works & operates the same as a properly operating OE clutch.
It disengages between 3000 to 3500 rpm, for the last 3 years I've had it.

Mine was purchased in 2009, and installed in 2011.

So it depends on luck of the draw from what I've seen. I'm very satisfied with mine.

 

[gsxr]

It would be nice to have someone confirm the RPM of disengagement on a recent-production ACM.

Don't forget that to use the ACM clutch, you must either cut your old bolt, or order a new shorter bolt from the dealer... details are posted earlier in this thread somewhere.

 

[clarkz71]

Someone has to buy & install one, maybe take one for the team ?

I went to Ace hardware, they have nice stainless bolts. I counted the threads exposed on the OE clutch /bolt
and took the ACM with me and got a bolt with the same amount

 

[Glen]

I put an ACM in the high miler earlier this year. It's been working great.
I can try testing the disengagement point when I get the car back from the paint shop...

 

[8899]

I just installed an ACM fan clutch a couple weeks back. I'm pretty certain that, prior to installation, it had been several years that the fan clutch was not working at all. In fact, I was able to remove my cool harness as a result. I will also try to test disengagement point. At what RPM should it disengage? Do ambient temperatures have any impact on engagement/disengagement?

 

[gsxr]

I just installed an ACM fan clutch a couple weeks back. I'm pretty certain that, prior to installation, it had been several years that the fan clutch was not working at all. In fact, I was able to remove my cool harness as a result. I will also try to test disengagement point. At what RPM should it disengage? Do ambient temperatures have any impact on engagement/disengagement?

The clutch should disengage at 3500rpm. Yes, ambient temps can affect it, but if the clutch is engaged consistently at 3000rpm, it will probably remain engaged all the way to the decouple point (3500rpm or beyond).

 

[Klink]

From everything I have read here on 500Eboard, it sounds like the ACM is the way to go. It seems that they have a consistently correct cut-in temperature, and I have no reservations whatsoever about a higher cut off RPM as as long as the fan speed stops increasing by around 4500 or so crankshaft RPM. Seized 119 fan clutches do not explode the fan until above redline. Don't ask me how I know. I am convinced that only the bearing of the ACM clutch is "made in China" and not the entire unit. For that matter, that's where a lot of bearings are coming from nowadays.

I honestly cannot tell you for sure if brand new "genuine" 119 fan clutches are not still completely hit or miss for cut-in temperature. I haven't replaced an OEM Sachs clutch with a new unit in at least 13 years. They are almost always completely unworn and have not leaked out. They simply need tweaking until they actually operate, which is something they generally have not done since they were first installed on the vehicle. Don't ask me to tell you how to do it. You will destroy your radiator and blame me. And even if you manage to not destroy your radiator, you are going to have to take it in and out of the car and re-tweek it six times to get it just right. Since somebody is now making one of these things that actually works, muddling about with the Sachs unit just isn't worth the trouble, IMO. Maybe Horton has fixed them since acquiring the operation, but even then the price is ghastly. It looks like the thing to do for most people, is to just buy an ACM and be done with it...

 

[clarkz71]

Considering the price difference, ACM is worth a shot.

.

 

[gsxr]

...It seems that they have a consistently correct cut-in temperature...

My ACM also had an incorrect cut-in temperature. They engage at a MUCH lower temperature, like, below 70C engine temp. So, it runs practically all the time unless there is snow in the air and ice on the roads. Some people may like this, as it will help with engine cooling in warm climates. Doesn't work for our particular needs, but I can count the number of folks who drag race their 036's on one hand. The factory clutch is generally not engaged until the engine is over 90C with the AC not running. (Running the AC increases the heat load present at the bimetal strip, and helps trigger the clutch sooner, regardless of engine temp).

...I honestly cannot tell you for sure if brand new "genuine" 119 fan clutches are not still completely hit or miss for cut-in temperature.

My experience confirms this as well. Are you feeling... lucky?

...Don't ask me to tell you how to do it. You will destroy your radiator and blame me. And even if you manage to not destroy your radiator, you are going to have to take it in and out of the car and re-tweek it six times to get it just right.

BT, DT, have a destroyed clutch and radiator to show for it. Don't try this at home if your name isn't Klink.

 

[Glen]

So, it's hit or miss with the OE clutch and possibly over cooling with the ACM. Hmm.

 

[gerryvz]

Several folks (Jelmer and Christian_K among them) have installed electric cooling solutions.

How's all that working out vs. a fan clutch?

 

[Klink]

Thanks, Gixxer. That definitely merits some thought, and perhaps I spoke too soon, as too low a cut-in temperature misses the whole point also. I'd be happy with anything between 85 and 95°C coolant temperature. For one to turn on at 70° means it's coming on pretty much the second any warm air hits it, and most people's first time tweak attempt on a Sachs yields them exactly that. For what it's worth, tweaking them to a higher cu-in temperature is easier and less risky than tweaking them to a lower temperature. I will look into this and study the ACM a little bit more when I get the chance.

 

[clarkz71]

Once again, my experience is the opposite.

I rarely hear my fan, only at cold start which is normal.

If I get into traffic for an extended amount of time, I may hear it over 90°C for a short time

It disengages in a short amount of time, or if I exceed 3000 rpm.

My coolant temperature is a steady 80-85°C 90% of the time.

 

[samiam44]

Similar to Dave's nightmare rear wheel bearing replacement. My clutch on the 500e had been WAY over tightened, I firmly had the allen seated and with lots of force, the bolt stripped out without a hint of loosening. It resulted in the use of the blue wrench which was almost impossible in the location. I could not get square on the head, but the aluminum housing of the cluch melted/broke. Once the preload was gone- it backed right now. Used lots of wet towels to prevent damage from splatter. WO, close because backup plan was to pull the motor *OR* remove the condenser!!!

That said- I have a NEW production Horton(OE) and it works very well and my other car has a ACM circa 2011 and it does not disengage at 3500 rpm. This last batch of Horton clutch - maybe they are better or I got lucky. Either way, I'm good. 420e rarely gets the same number of redline shifts as the 500e, so it is fine.

 

[gsxr]

...my other car has a ACM circa 2011 and it does not disengage at 3500 rpm.

Michael, did you ever test what the RPM is when the ACM disengages? Mine was consistently at ±4500rpm.

 

[gsxr]

...I have no reservations whatsoever about a higher cut off RPM as as long as the fan speed stops increasing by around 4500 or so crankshaft RPM. Seized 119 fan clutches do not explode the fan until above redline. Don't ask me how I know.

How do you know, Klink? (kidding!) If the the fan blade is safe to ~6000rpm, that is good news. And it probably explains how the fan survived when I briefly tried a Vemo clutch that never disengaged before redline. (!!)

 

[samiam44]

gsxr,

I did test mine and it disengaged around 4500 rpm. I did state that before b/c the number is from memory.
All parts are designed with a factory of safety. Magnesium has very little elongation, so I would guess 2.0 (guess). So your operating on margin with a cut-out failure. MB engineers may have designed 1.5X max load @ 6000 rpm and assume the cut-out fails.


Michael

 

[gsxr]

Thanks, Michael! That is two confirmed ACM clutches disengaging at 4500rpm. Good point about the built-in margin, too...

 

[clarkz71]

Hmmmm, I found an old image of my fan clutch.

It's marked KM Germany, a company that is actually German

Though it looks like they only make actual clutch parts for drivelines now.

I bought this in a Febi box in 2009

http://www.kmgermany.de/home.html?L=1

 

[gsxr]

Very interesting. The Febi unit appears to be very similar to ACM and Vemo. I've never heard of "KM" before.

 

[clarkz71]

Very interesting. The Febi unit appears to be very similar to ACM and Vemo. I've never heard of "KM" before.

It could be why it works perfectly.

It turns out it's not an ACM, I thought it was coming in a Febi box

It was 5 years ago when I bought it..........

.

 

[clarkz71]

Very interesting. The Febi unit appears to be very similar to ACM and Vemo.

I think you mean "Febi Boxed" unit. There is no Febi manufactured clutch.

 

[gerryvz]

I think you mean "Febi Boxed" unit. There is no Febi manufactured clutch.

+1

 

[gerryvz]

Just so folks know -- there is some good fan clutch information in the Wiki at this link.

For informational purposes, the MBUSA list price for the E500E fan clutch (119 200 01 22) has gone up to $870.

 

[8899]

I've been running my new ACM fan clutch for about a month now and have noticed that it disengages inconsistently between 3000rpm to 4000rpm. It seems that when I hold the transmission in 2nd gear and am at heavy throttle it will disengage later (right around 4000rpm) but if held in 3rd gear and am at light-to-medium throttle then it will disengage at around 3000rpm. I've never heard it disengage at 4500rpm. All said, engine temperatures are consistently lower at around 80* to 85* C.

 

[gsxr]

I've been running my new ACM fan clutch for about a month now and have noticed that it disengages inconsistently between 3000rpm to 4000rpm. It seems that when I hold the transmission in 2nd gear and am at heavy throttle it will disengage later (right around 4000rpm) but if held in 3rd gear and am at light-to-medium throttle then it will disengage at around 3000rpm. I've never heard it disengage at 4500rpm. All said, engine temperatures are consistently lower at around 80* to 85* C.

Greg, with the engine hot and clutch engaged, you can rev the engine slowly while in Park and determine the exact cut-out point. After it cuts out, let the engine return to idle for 5-10 seconds, this should allow it to re-engage. You can repeat the test a few times and generally determine the decouple point within ±100 RPM.

Remember that if the ambient temp is cool, it may disengage at a lower RPM than the "max RPM cutout". The fan clutch is an analog device, not digital. It can be "partially" engaged and decouple at, say, 2000rpm. That's why you need fairly warm temps for concrete testing.

 

[Trae]

Greg, I think your clutch may be OK.

Here is the test:

How to check:

The mechanical fan clutch should be fully engaged with the engine temp at least 90C and in high ambient temperatures (>90°F). If it's not engaged by 90-95°C on a hot day with the AC running, the clutch may be defective. With the car in park and engine temp at 90C or higher, pop the hood, and rev the engine slowly. The fan should roar loudly up to 3500rpm. With the OE/Sachs clutch, you will hear it disengage by approx 4000rpm, then let the revs drop slowly and the fan should audibly re-engage by ~3000rpm. If yours doesn't do this, either (1) the clutch is bad, (2) there is not enough ambient heat to trigger the bimetal strip, or (3) there is a blockage directly ahead of the clutch restricting the airflow needed to trigger the bimetal strip.

Note: Some aftermarket clutches (i.e., Vemo) may not disengage before the ~5000rpm limit of the EZL with the engine in park/neutral, this is not good. The ACM clutch will disengage at a higher RPM than OE/Sachs, usually by approx 4500rpm; and may not re-engage until the revs drop below 3000.

 

[Klink]

I've been running my new ACM fan clutch for about a month now and have noticed that it disengages inconsistently between 3000rpm to 4000rpm. It seems that when I hold the transmission in 2nd gear and am at heavy throttle it will disengage later (right around 4000rpm) but if held in 3rd gear and am at light-to-medium throttle then it will disengage at around 3000rpm. I've never heard it disengage at 4500rpm. All said, engine temperatures are consistently lower at around 80* to 85* C.

Those cut out RPM ranges in and of themselves are no problem whatsoever. Always remember that the function of these things is to bring in cooling air at relatively low vehicle speeds. Your car is always moving fast enough to cool adequately at by engine speeds of about 2000 RPM. That is another reason that the rpm dependent cutout exists.

It is also possible that those times where you noticed a lower cutout speed you were simply seeing a thermal switch off taking effect. When engaged, the fan really cools things off fast. If the bi-metal strip cools enough as the RPM increases, the fan will disengage before the RPM dependent cutout takes place...

 

[gerryvz]

Indeed, he's back to my favorite avatar.

 

[Klink]

Yeah, The Colonel avatar is back!

Never could figure out the Smart car thing.

Of course, the sweet girl polishing the STAR was hit for some reason. . .

I'm sure the hood star detailer girl will make a return one of these days as well. She was last seen with this guy: She always did perk up at the mention of "ole one eye".

I'm sure she'll come back when the money runs out. They always do...

 

[whitehawk]

Anyone have the special pulley holding tool (or a fabricated similar tool) that I can borrow for a couple of weekends? I can send a Fedex label for the shipping and will promptly return.

 

[gerryvz]

Anyone have the special pulley holding tool (or a fabricated similar tool) that I can borrow for a couple of weekends? I can send a Fedex label for the shipping and will promptly return.

I think a couple of folks here (Glen?) have made them on their own. Buying one is around $50 online if you look around .. purpose-made tool.

 

[Glen]

I made one, here's a picture:

I certainly don't mind sending it to you, its only about $8 in steel. If you have access to a welder you can build one in about 30 minutes. If a welder isn't available, you could probably bolt one together. Either way, PM me if you want me to send it out.

 

[clarkz71]

I think a couple of folks here (Glen?) have made them on their own. Buying one is around $50 online if you look around .. purpose-made tool.

More like $100 to $120 for factory tool

I'll post a pic later. But it is nice

 

[gerryvz]

The factory style 65mm fan clutch wrench can be had online for under USD $20, new.

Here's an example, on eBay.

http://www.ebay.com/itm/Bergen-65mm...0614196785&pt=Motors_Automotive_Tools&vxp=mtr

ADMIN EDIT: This tool does not work on the 119.97x engines, see post #299 for details.

 

[clarkz71]

That' not the factory style tool.

I'll go down to my garage and grab the MB tool

 

[gerryvz]

Clark's in major 589 mode today.....LOL !!

 

[clarkz71]

Clark's in major 589 mode today.....

No, I'm in correct information mode. Price has come down though. P/N: 603-589-00-40-00

MSRP....... $87 from MB

Samstag sales gets $99




.

 

[gerryvz]

I'm very familiar with that tool, and yes you are 100% correct that it is the factory tool.

I just prefer the Glen-style one that grips the bolt-square on the pulley. And note that I said "factory style" ...not FACTORY. It is a professional tool and quite a number of firms make these 65mm fan clutch pulley wrenches.

 

[clarkz71]

Only problem with the "spanner" style wrench is they can slip.

The original style tool has a good purchase on the pulley, no way that will slip.

And ooops, hit the radiator.

 

[whitehawk]

Thanks Gerry, I'll get this one from eBay UK. Least expensive route even though I'll have to wait a few weeks for it to arrive.

 

[whitehawk]

The factory style 65mm fan clutch wrench can be had online for under USD $20, new.

Here's an example, on eBay.

http://www.ebay.com/itm/Bergen-65mm...0614196785&pt=Motors_Automotive_Tools&vxp=mtr

That tool doesn't work for this application. I received it from the UK this past week and here are the results. Too thick!

 

[Dbreid]

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?

 

[8899]

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

I have had the ACM clutch installed since last year and think it works well. I say that from the perspective of never experiencing how a good OE clutch works in comparison to the ACM. However, in terms of keeping the engine cool, my ACM clutch does a great job at that.