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Tell you what, Mr. 7 posts.

Do a citric acid flush, and replace the thermostat, fan clutch (genuine new MB unit only), radiator and see if you still think the aux fans are part of the cooling system.

The aux fans primary function is to cool the condenser, and only as a EMERGENCY push additional air into the engine bay.

The clutch fan is the primary cooling device.

FWIW, I've had these motors drop up to 20F just by doing the acid flush.
 

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I may have 7 posts but have the same W140 S500 for 23 years - the electric fans switch on at low speed in stop start traffic conditions in hot weather even if the cooling system is in good condition! (The fans are inaudible inside the cabin)
 

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get the discussion back on topic guys. we're not discussing electric fans or w140s.
 

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Discussion Starter #64
I think that's okay since W140 came as one of possible replacements (related to the topic of the thread) sometime in this thread. I could use some info if by a very micro slim chance W140 gets to be it.

I need to know. Has any one lived long enough in a cold area (max 35c in summer) and in a really hot area (up to ~50c in summer) with a W140 to experience and feel (almost) everything of how it fares in the two climates?
 

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Let's just put it this way. My W140s, both with the notoriously hot running V12s, never touch or exceed the 100C mark not even on the hottest of days which is between 35C-40C here. Normally, the gauge stays between 80C-90C

The only way to make the gauge move beyond the 100C mark and trigger the electric aux fans would be by leaving the car idling for around 90 minutes and only during such hot days.

Anybody who believes splicing in resistors is "the cure" needs to face reality and fix their cooling system properly. If you believe that your temp gauge should never move, splice in the proper resistor on the back of the instrument cluster and it will read whatever you want it to be, even if your engine is about to go Chernobyl.
 

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Start a w140 specific topic or use the w140 forum for that.
 

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Discussion Starter #67
This won't take long, I think I got my answer up there. This is gonna be the last reply for aux. fans from my side ;)
(this is W140 exclusive)

The only way to make the gauge move beyond the 100C mark and trigger the electric aux fans would be by leaving the car idling for around 90 minutes and only during such hot days.
I think that's it. such conditions (and others that could be even worse actually, like stop and go traffic and tunning the engine off and on under compulsive conditions) do exist and take place even if one thinks they never do. Sometimes I'm forced to stop and go for more than three hours! That's worse than 90 minutes idling.

Daily drivers can tell as much, and I am one. It's a big world with different people with difference circumstances.

Coolant Temp. would still be within specs and safe even then, we know, but users just don't want it due to personal reasons like not wanted the A/C to lose cooling and to protect A/C parts further (compressors do die faster because of heat, that's a fact). Or simply because they don't want it, easy.

Those hacks then (for such conditions, not with real problems) would simply give a peace of mind. Plus, they don't hurt if done within reason like reducing high fan starting point from 107c to 100c. It will just run earlier once then never again. If there's a problem, never resort to such hacks. Fix the problem first.

However, if the climate is never extremely hot (less than 40c) I personally would never resort to such hacks and I'm completely against it. Keeping your car stock is better.

Okay, aux. fan talk is over now. Please back to topic (I'm the thread starter).

This thread can be locked now, if admins see fit. I have similar questions in the W212 section and it seems members started to notice them and give answers.

Cheers!
 
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