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Installed an electric fan

33K views 37 replies 14 participants last post by  Djenka018 
#1 · (Edited)
I replaced my stuck fan clutch with an electric fan. The most difficult part (for me) was to take the old fan clutch out. I had to ask my mechanic to do it. The fan installation is pretty straight forward.

Pic 1: The battery is in the truck for my SLC, so I have to find a 12v source under the hood. With help from this forum, I found the 12V source near the passenger side. Also found the ignition switched 12V and ground nearby. The switched 12v turns the fan off when ignition is off.

Pic 2: Electric fan installed. Plenty of room now.

Pic 3: Bought this 16" fan from ebay. Brand new for $30. It claims to draw 12.4amp with a 2500 CFM rating. It fits perfectly to the SLC radiator.

Pic 4: Also bought a Derale adjustable temperature fan controller from the same seller for $45. Came with wiring harness, fuse and one page instruction manual. It was preset to turn on at 103 C. I adjusted it to roughly 95 C.

Result: Quiet. The car is much more quiet than the old stuck fan clutch. I also noticed some horsepower gain at high rpm. The new fan is more quiet than the auxiliary fan as well. With ambient temperature around 80F, the electric fan turns on at 95 C and coolant temperature stays at 100 C at slow traffic.
 

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#4 ·
Just want to give an update on this project after 1.5 years.

Good:
* I have no electrical problem after the installation. i.e. the r107 alternator has enough juice to power the electric fan.

Suggestions for new installers:
* Protect the Derale adjustable temperature fan controller: After a couple rainy days, the rain water somehow leaked under the hood and shorted the fan controller. :( I'll suggest putting the controller inside a small plastic box (like a small lunch box).

* The $30 ebay electric fan has some vibration after the engine warm up. I suspect the fan blades probably out of balance under high temperature. I suggest you either mount it very tight or get a better quality electric fan.
 
#6 · (Edited)
Good write-up. I have nominated it for EGv107.

Been thinking about this a bit...
If you don't mind, a few of questions: 1. How did you mount the fan?
2. How is the temp sensor mounted up (from where are you sensing temp)?
3. Did you use the clutch bolts to hold the water pump pulley on the water pump, or have to buy shorter bolts?

I have been investigating the S25/5 temp sensor for the aux fan on a 1988 560SL. It is 2 switches in one, designed to turn on the aux fan at 105C and turn Off the a/c compressor at 115C. If one was to use the 105 leg, and adjust the temp to 85-90C, I think the aux fan could substitute for the viscous clutch/fan, and quiet the engine bay down tremendously. If the aux fan is not large enough volume, then replacing it seems like a better option than having two electric fans. Besides, the wiring, etc is already in place on the aux fan...

Anybody else got any thoughts?
 

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#8 ·
If you don't mind, a few of questions: 1. How did you mount the fan?

2. How is the temp sensor mounted up (from where are you sensing temp)?

3. Did you use the clutch bolts to hold the water pump pulley on the water pump, or have to buy shorter bolts?

I have been investigating the S25/5 temp sensor for the aux fan on a 1988 560SL. It is 2 switches in one, designed to turn on the aux fan at 105C and turn Off the a/c compressor at 115C. If one was to use the 105 leg, and adjust the temp to 85-90C, I think the aux fan could substitute for the viscous clutch/fan, and quiet the engine bay down tremendously. If the aux fan is not large enough volume, then replacing it seems like a better option than having two electric fans. Besides, the wiring, etc is already in place on the aux fan...

Anybody else got any thoughts?

1) My electric fan came with mounting kit which is basically Plastic tie straps & holders along with rubber padding. You can get it from ebay for a few bucks.
The mount kit works fine as long as the fan don't vibrate. For my setup, the e-fan is supported by the bottom of the radiator. The mounting kit just hold it in place.



2) A thermostat stick came with the controller kit (see the last pic). I just push it into the radiator fin near the upper radiator hose.

3) I put washers in between. I read on the forum that some people just cut the bolts to shorter length.

In my experiment with r107 and w124, the aux fan is enough to cool the engine. The dual aux fan in w124 is very strong. I had ran both car without viscous clutch/fan for a few months. Yes, it works but the aux fan is a backup in case of the viscous clutch/fan fails. There is a risk running aux fan-only.
 
#7 · (Edited)
^ ^ ^ ^ ^

I think I read somewhere that there was a difference between drawn and pushed air in terms of cooling when there was a two radiators setup (one infront of the other).


EDIT:

Here is a basic redundant safety dual speed dual fan circuit I contemplate as a simple setup.
Both fans connected in series @ 95*C (before full on speed) would reduce startup current and would allow thermostat to play major temp control.

Should series fan circuit fail, at 105*C main fan would kick in at full blast.
Otherwise, if insuficient airflow at hot temp with both fans at low speed, both fans would kick in at 105*C
 

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#10 ·
Why Not do it?

Why:
1. Positive engagement, more effective Cooling
2. Remove parasitic drain on engine from fan/clutch
3. Noise abatement when cooling not needed.
4. adjustable, tailorable to specific needs
5. because...
 
#21 ·
IMO, fan shroud is functional only at low fan speed and is a trade off.
At high vehicle speed it is an obstacle but it improves cooling when fan/engine is at idle or low rpm (like in traffic jams).
With new electric fan that either runs at full speed or it does not run a all, it would not make any benefit having original fan shroud. Actually, it would be quite opposite.
 
#25 ·
The fan is fixed to the shroud itself (see right of picture bolt head and bracket). The fan has 4 securing points for a 10mm bolt on the outer rim and a set of 4 "L" shape brackets can be sourced from your local hardware store:- 40mm longest side, 30mm short side X 15-20mm wide.

Took off the shroud and placed flat on a bench, centred the fan on the shroud and marked the points for drilling. Took 30 minutes.

I did not install the thermo-switch that came with the fan, (the one that goes inside the top hose) as I found it cumbersome and unsightly, instead I obtained a Mercedes 100C thermo-switch and installed it on top of the coolant pump (the red thermo-switch to the left of the oil dip-stick in the pic) by removing the original closing plug bolt that some 107s have installed for the optional auxiliary fan. The wiring for an additional auxiliary fan was already within the original MB wiring harness. I simply added the kit relay.

Initially I found the engine was running too hot as the constant viscofan cooling effect was no longer there. Subsequently I installed a negatively closed (positively opened) thermostat, part number: 000 589 74 6300 (no longer available, Mercedes used to supply this thermostat to hot countries) but an ordinary standard thermostat can be easily modified to became a negatively closed thermostat.

Since I installed the fan back in 2002 the engine runs beautifully and cool as a cucumber (around 80C city traffic or highway).

Benefits is noticed: better fuel consumption, (less pollution) a slightly increased HP and much quieter running. I never looked back to the cumbersome viscofan. You did well by installing an e-fan Bigwiki. :thumbsup:
 
#28 ·
One of the ideal models for the 107 is the SPAL
VA33-AP71/LL-65A Fan (16" HP)

Though mine is a Kenlowe 16”. If you do get one don’t forget the L-shaped brackets available for that fan from SPAL. I am no so sure about dual speed but the controller for the W220 cost more than the fan!! and is not really necessary, methinks.

 
#33 ·
Instead of dual thermo circuit, a delay circuit with a single low temp thermo switch could do the trick.

At say 85°C it would engage fan via resistor (for slow fan speed) for maybe 5 min after which it would blow the full blast until it resets.
It would reset only when thermo switch cuts out (meaning coolant temp is brought down).

This way, if slow fan speed provides enough cooling within first 5 min of cooling, thermo switch will cut out and delay timer is ready for new 5 min cycle.
Otherwise, after 5 min of attempted cooling at low fan speed, full fan blast would engage for as long as it is needed and, upon completed cooling cycle, it resets again.

If there is a general interest for this electronic circuit, I can provide PCB layout and schematic diagram for easy assembly with generally available components.
 
#34 ·
Doesn't even need to be that complicated. Use a dual speed fan, have low speed connected with key on and set the high speed to come on at whatever temp you choose via water temp sensor. Having the fan on all the time at low speed will clear your engine compartment of fumes and heat while idling in weather that won't make the high speed engage.
 
#35 ·
While not a bad idea in my opinion, this may prolong the engine getting to running temp. This is not a desirable situation... It would have to be a very slow speed, around 500-600rpm. This would mimic the viscous coupled fan, if I am remembering the specs correctly.
 
#36 ·
Wait -'not desirable'? This is how the OEM viscous coupled fan worked. It ran and moved air ALL THE TIME. It just forced air faster when warmed up to the point the coupler locked up. Remember that the engine is being warmed from the inside - out, not cooled from the outside - in. Heat moves to cold.
 
#37 ·
Re-read... What is not desirable is to have the engine warm-up prolonged, not that the fan moving air is not desirable. Notice the comma and period in the appropriate places :)

While not a bad idea in my opinion, this may prolong the engine getting to running temp. This is not a desirable situation... It would have to be a very slow speed, around 500-600rpm. This would mimic the viscous coupled fan, if I am remembering the specs correctly.
Also, I mentioned the viscous fan and said the electric would need to mimic it... providing a reference to the speed for the low setting.

OK... maybe air moving around the engine before the stat allows flow to the rad is irrelevant. I did not mean to step on any toes... Jeez...
While not a bad idea in my opinion,
 
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