Whoops, slight error in my post - it should have read that I've replaced the fluid twice, not the actual clutch. That's my next job!

Duke2.6 and pberku's testing suggestions are correct but you definitely have the elder clutch - it has no electronic governing system as so will react as suggested.

Just a couple of points to correct some of the previous posts; the fan doesn't need to be cold but simply left standing for around 15minutes. This is usually long enough for the fluid to change from chamber 2 to 1 under gravity and it's in chamber 1 which the fluid grips the fan.

According to MB data the fan will rotate at half engine speed until 90-105degC (air exit temp) which translates to around 85-95degC water temp -due to losses, thermal relief in engine block etc.

I used to own the same exact car and yes it should 'roar'.

You will also note the design is such that it will also disengage at >=4500rpm for efficiency reasons - MB assume that there is plenty of air traveling through the rad at this high rpm and you're not still and simply just reving.

Your symptoms do seem to indicate that it is indeed cutting in when hot, but I wonder if you have lost fluid and so the fan isn't attaining the correct rpm. I have exactly this with my current 500SL and have to top up every 6 months as gradually the fan rpm slows (the clutch progressively slips) and engine temperature slowly increases.

Lea

__________________
'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

http://antron.pwp.blueyonder.co.uk/i...nature/Sig.jpg

. . different models but my vfc starts to cutin around 100C because that's where the bimetallic switch (bms) bends enough to allow the 'juice' to flow into the proper chamber.

If you look at MENU#21 where I tested the bms, you can see that it around 100C there is enough bending to engage the vfc. So you can see that to get 100C EXIT temp, the engine coolant has to be MORE than 100C, thus the complaint against the vfc operation. "AIR" is the coupling medium that causes the bms to bend. So for the bms to bend enough, the engine temp has risen way over 100C probably 110C+ to get 100C air temp. That's why the vfc mod described in MENU#20.

I tried to get some companies interested in making a lower temp version bms. But after some initial interest, nothing ever came of it. The target was 90 -95 coolant temperature.

The other point is the cut-out point is around 3000-3200 prm. That represents about 85 - 90 mph.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

I have to chirp in here about the suggestion one stick a towel or rubber hose in the fan while it is turning. I am a paramedic and attended to an incident a number of years ago where a mechanic was doing exactly that. I piece of the fan broke loose and struck him in the neck, taking out the carotid artery, internal and external jugulars. Needless to say, such an injury is not compatible with life. He bled out almost instantly.

The idea of heating the car up and shutting it down and testing if the fan has stiffened up seems way more sensible.

Play safe everyone

What kind of fluid can I use to replenish the clutch??

__________________
190e 2.6 1990. 300,000 KM
C230 K 2000, 130,000 KM

If your fan is not working properly,then before jumping ahead and adding fluid, take it apart and clean all of the accumulated dirt the bimetal spring.

Too much dirt jams the bimetal spring, preventing it from bending and activating the fan.

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

I cannot image the amount of dirt/grime that would need to stop the bi-metallic strip - have you ever removed one? The strips produce significant force!

Jim

I'm sorry, but I don't either understand your rational or our bi-metallic strips are quite different or that our coolant sensors are mounted differently.

The BMS will deflect at 100degC as your tests prove, but this is air exit temperature of the rad, so one assumes that the rad MUST be greater than 100degC - agreed. BUT, I mention water temperature. On the 500SL the coolant temp sensor is on the exit side of the rad and as soon as the fan engages the rad will almost instantly cool the water on exit. The key I think is the thermal mass surrounding the sensor, which is significant and so the displayed water temperature (in the R129 at least) never reacts quickly. Mine never gets above 85C as the fan cuts in at 82C. New temperature sensor in mine also.

My assumption is that the engine mass acts as a low pass filter and averages the temperature changes displayed. But this is based solely on my R129 and general understanding of physics.

I can only assume that your temp sensor is on the input side to the rad with no surrounding mass - that would explain why you see higher coolant temps on the S class before the fan cuts in?

Otherwise I don't understand why you see such high temperature. Car manufactures do not make such fundamental mistakes and engines are designed to run at 85-90DegC as this provides the optimum - which the R129 ('93) does fine.


Lea

__________________
'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

http://antron.pwp.blueyonder.co.uk/i...nature/Sig.jpg

See here for info on refilling:


Viscous Fan/Clutch

__________________
'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

http://antron.pwp.blueyonder.co.uk/i...nature/Sig.jpg

bannanas! I was only talking about the VFC and when it "engages". Maybe we do agree but based on a bms that 'opens' at 100C, then the radiator water temp MUST be significantly higher than 100C for the bms to open at 100C..

The reason, based on physics, is based on the transfer coefficient between the radiator's 'metal' (aluminum) and the transfer medium, "air". As you may know, stagnant air is one thing but moving air is a severe complication b/c the air is mixed with cool air and the rad's hot air in and around the surface.

Since there's a goodly amount of air moving through the rad's fins, the air 'landing' on the front of the VFC (and thus bms), is much cooler than the rad's internal temp. Since the BMS responds to the air temp, it not unreasonable for the temperature in the rad to be 110 - 120 degsC so that the bms "sees" 100C.

You say that portion of the MB system was 'properly' engineered but as you can see, it's practically useless. Only when the rad temp is at a 'dangerous' point is there a chance that the 100C bms will operate.

This is not just my opinion but many learned people share the same opinion. But MB DID recognise the failure of this system and there is a vfc unit that is designed for the tropics that does operate at 85 - 90C (bms is 'bent' fully at 90C) or so. The discussion is an interesting thread here on the MSF.

I don't care where the temp sensors (B10/8) are on the car, since that has NOTHING to do with the operation of a vfc.

If the aux fans system is 'thrown' into the mix, then it certainly operates MUCH earlier than the vfc. For a "S" class car, the aux fans are set to fire off at 100C for the first stage (low speed).

As you can see, that dampens the operaion of the vfc since the aux fans 'cool' the air down further preventing the vfc operation.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Don't get me wrong, I agree that for the bimetallic strip to operate the water temperature in the rad must be greater than the operational point of the strip, however, the coolant temperature monitored by the sensor may not be the same! It's the temperature surrounding the combustion chamber that's critical to efficiency and power output - not the rad temperature! Just because the rad input is at 110C doesn't mean the engine is.

I am the first to admit that I may have missed the obvious, so if someone can explain why the M119.067 engine runs perfectly within the 85C-90C, as designed, and seen on my water temperature needle, then please do....

Lea


Edit...

Maybe I should mention that my reference to 'fan cut in' temperature is always the coolent gauge within the car. Maybe I'll mount a thermocouple to the rad this weekend and monitor the rad temp direct?

But, who cares for rad temperature? It's block temperature surely that's the main reason for cooling in the first place.

__________________
'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

http://antron.pwp.blueyonder.co.uk/i...nature/Sig.jpg

cooking! Ok, so the rad temp MUST be higher (quite a bit higher) for the bms to operate. We agree.

But we still don't agree on eng temp vs rad temp. How can I say this?? I'll bet you a "dollar" that your eng temp as measured on the front aluminum header, is HIGHER than the rad temp. To prove this, get a infrared or laser temp sensor, and simply point it at the rad and engine. Move it around and take some readings.

And I believe that you'll find that your temp gauge is on the low side. The M119 engine gets nice and hot especially if you idle it on a nice hot day. Easily gets to 100C. Remember that your eng is in smaller enclosure (like the 500E / E500) than my car, so it's get's even hotter.

Be interested to see what you read.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

LOL...

Jim, I'm just trying to understand why our machines are soooo different and of course applying what limited knowledge I have - however that isn't particularly based on experience or expert opinion!

A dollar - that's 50 pence to me ....LOL... OK you're on. I know when loosing isn't gonna hurt me much..

Thinking again, the heat MUST come from the block in the first place so maybe I agree..... If the source of heat is the block, then maybe it is hotter than the rad (as you say) and therefore a bi-metallic strip rated at 90-105C is a poor choice considering the electric fans engage at 110C.

So why does my sensor say 85C and never move - no electric fans, just viscous coupling at a reading of 82C-85C! CONFUSED!!!!

edit....

Who designed the poor electronic sensing system in the 129 then? Let me at them! If the coolent sensor is reading as Jim mentions (and maybe it is) then my gauge is simply completely out.

Assuming it's out by 15DegC matching yours - how can MB design such a poor system? Especially after the level of testing all cars undertake!

Time to get the thermocouples out - and of course the laser meters... I'll let you know....

__________________
'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

http://antron.pwp.blueyonder.co.uk/i...nature/Sig.jpg

that in the newer MBs they have purposely damped the temp gauge so that, as I was told, it stays in a plateau portion and doesn't move. The movement of the temp gauge over 100C and beyond is one of the most 'dreaded' things for an MB owner. Thus the damped/flattened mid portion. Personally, I've not seen one.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

52p according to my morning paper.

Us statsers have to stick together.

If I get my hands on some Sachs clutches I'll let you know

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Although your "Physics" may be sound, some of your assumptions are not.
When Mercedes specifies an activation temperature of 100C it already took into account that the air temperature is cooler than the coolant temperature. So the Fan was designed to come on when the air temperature is approximately 90C-95C which roughly corresponds to a coolant temperature of 95C-100C. Exceeding that temperature should cause the Auxiliary fans to come on.

If the VFC would have indeed only been triggered at an equivalent coolant temperature of 110-120C as suggested, than it will always come on AFTER the auxiliary fans have already kicked in at their lower set temperature of 100-105. This is not the case. The VFC normally activates BEFORE the auxiliary fans do.

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

can get another $1.00! You are not even close, sorry! Before you hang yourself any further, check my web page, MENU#21. You will see bms just starting to bend at 100C. Actually, both bms sat in there (boiling water) and really didn't bend until the water really vigorously boiled. So until the bms bends, no vfc. Now there's proof that you are not correct. Since the transfer coeficient from alum to air is definitely less than unity, the rad coolant MUST around 110C or higher.

No, in fact, the vfc is a LAST ditch system that was designed to operate at higher (much higher) than normal temperatures to protect the engine. It is NOT like the aux fans, which were designed to come on at 100C.

The VFC NEVER activates before the fans. As I pointed out, there are some newer versions of the vfc that activate earlier. This means the bms bends at a lower temperature. These units are being sold in the tropics. But for the years that Lea and I are talking about, 92 - 96 or so, the bms is a last device to kick in. The proof is in the pictures!

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page