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I never could understand how laying a fan clutch assembly on it's side instead of straight up would cause it to fail. Can anyone explain this?
It's the weight of the fluid on the seals in that position....it's designed to orient vertically at all times. It probably takes a long time in storage, laying down, for the adverse effect, but it does happen on occasion.

Kevin
 

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Out of interest what is the solution?
On the om603, 2 electric fans one pusher one puller driggered by a temperature switch at 82c. On the om606, I'm setting up dual puller fans from a Prius (the only fabs thin enough to fit in the space) triggered by a temp switch at 82c. On the m102 powered 190e one very powerful puller fan from a Volvo triggered by megasquit at 87c.
 

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I got scared once while stuck in traffic while driving the E320 cab, the temp gauge started flirting with the red zone. Fortunately the top was down and the AC was off.
I bought a device called a "cool harness" which is basically a resistor that goes in parallel with the coolant sender to bring the aux fans in at 95 Celsius.
It seems to work very well - no more scares.
 

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As Nobletruths stated earlier, IF you have a properly functioning cooling system there is never any worry about running hot or the need to mod the system.

Read my post from a few years back. I went through the Behr clutch fans (both Chinese and German versions), only to settle for the OE MB clutch made by Horton.

Since then, it never touches the 100C mark even on the hottest of days.
 

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I got scared once while stuck in traffic while driving the E320 cab, the temp gauge started flirting with the red zone. Fortunately the top was down and the AC was off.
I bought a device called a "cool harness" which is basically a resistor that goes in parallel with the coolant sender to bring the aux fans in at 95 Celsius.
It seems to work very well - no more scares.
That is a really good solution on the later w124s with dual aux fans. Those 2 pusher fans while not ideal are powerful enough to cool the engine on their own IF triggered early with the cool harness. On early w124s with the single aux fan you're shit out of luck. On the w210 MB did a cheap cheat and only used one fan motor while driving the second with a small belt off the first. It's a crap setup.
 

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It's the weight of the fluid on the seals in that position....it's designed to orient vertically at all times. It probably takes a long time in storage, laying down, for the adverse effect, but it does happen on occasion.

Kevin
Thanks for the explanation....but it still doesn't make sense how the miniscule weight of a fluid can affect a seal that is subjected to much greater extremes like heat, pressure, expansion, contraction....

But we as W124 owners have much bigger fish to fry than a pissy little fan clutch.....:devil
 

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On the om603, 2 electric fans one pusher one puller driggered by a temperature switch at 82c. On the om606, I'm setting up dual puller fans from a Prius (the only fabs thin enough to fit in the space) triggered by a temp switch at 82c. On the m102 powered 190e one very powerful puller fan from a Volvo triggered by megasquit at 87c.
It seems a very complex solution to avoid replacing a fan clutch.
 

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... I doubt they would cover and collateral damage from a bad fan clutch....
Yes I doubt it too but a failed fan clutch doesn't result in collateral damage. We have all been talking about situations where engine temp creeps up in hot weather not cars that have exploded fan clutch bearings.
 

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Thanks for the explanation....but it still doesn't make sense how the miniscule weight of a fluid can affect a seal that is subjected to much greater extremes like heat, pressure, expansion, contraction....

But we as W124 owners have much bigger fish to fry than a pissy little fan clutch.....:devil

It's a long term, storage shelf phenomenon. And some of these fans sit a long time until sold and not necessarily in climate controlled warehouses.

Kevin
 

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The fluid is not pressing on the front seal in a vertical or face up position. Its when the clutch is left on its face that the very thin fluid can slowly weep from the front seal.
They are to be stored vertical or horizontal, but facing up (front to the sky).
 

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It seems a very complex solution to avoid replacing a fan clutch.
When MB or anybody else builts a fan clutch for the inline 6 that can maintain the coolant temp under 90c while sitting in traffic on a 100f+ day, I'll buy it. Until then I'll stick with electric cooling.
 

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The fluid is not pressing on the front seal in a vertical or face up position. Its when the clutch is left on its face that the very thin fluid can slowly weep from the front seal.
They are to be stored vertical or horizontal, but facing up (front to the sky).
I don't see any "front seal" on the clutch; do you mean the seal on the pin under the bimetallic temp sensor?
 

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When MB or anybody else builts a fan clutch for the inline 6 that can maintain the coolant temp under 90c while sitting in traffic on a 100f+ day, I'll buy it. Until then I'll stick with electric cooling.
They may have already built the specific fan clutch you are looking for. Check "Electromagnetic Fan Clutch."
 

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As I mentioned many moons ago, the bad cooling system rap the 124 cars are getting here in this forum is absolutely bogus. Whether it's the 'best' possible system the Germans could have designed is absolutely irrelevant. Cooling system problems were a non-issue in any climate in NA when the cars were new. They were way long in the tooth when all this balderdash started about 'design flaws'. Just like condemning 'German electronics' after 20+yrs of service.

Now you have owners putting in inferior radiators, cheaper clutch fans and water pumps, along with residual corrosion inside the engine blocks, bad auxiliary fans, aftermarket stats etc. You get all this sorted out, use OE components and you won't have cooling 'problems'.

I had an electromagnetic clutch fan in a Peugeot wagon. It was a good system, but what you may not know is that every time that electromagnet pops that fan hub together with its base, some metal is shaved off the two surfaces(one surface spinning, the other stationary). Once or twice a season I'd have to go in there with feeler gauges and adjust that gap...too big a gap and it won't engage reliably. I can't see how that system design could get around that and I don't think it was reasonable to adjust the gap that often by the owner.

Kevin
 

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I don't see any "front seal" on the clutch; do you mean the seal on the pin under the bimetallic temp sensor?
Correct. No "rear seal" because its a cavity in the clutch.
It may have a gasketed seal in the rear like this one though, but I think its more reliable than the front one under bi-metallic strip.

https://youtu.be/N_GkuTgJr3w

Here's a vid of a guy refilling a Toyota one https://youtu.be/3ACx7GTCn7Y
 

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who made the *original* MBZ fan-clutches ?

Do we have any anecdotal or otherwise evidence that the current MBZ branded clutches are short-lived? Its *very* possible that the ones MBZ sells and the ones Behr sells themselves are different quality. Of course, its equally possible they aren't, hence my query for evidence either way.
so here is what showed up today from the dealer brand new in factory box with emblem and part number on part made by behr
 

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