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DYI: Mechanical Fan to Electric Fan Swap

245K views 467 replies 143 participants last post by  jasondotcom 
#1 ·
Let me just start off by saying I know this has been covered before, but no one has given a definitive answer, so I figured I'd make a thread for future reference.

I have an auto, and our cars come with a mechanical fan (engine driven) as well as an auxiliary fan to help with A/C and extra cooling power.

However, when I installed my supercharger, I had to remove the Aux fan to fit the intercooler. Because of that, the car would overheat when sitting at idle for too long, or if I ran the A/C (which wasn't even cold). I had to find a solution. I started looking at aftermarket fans, while also researching if I could swap an electric fan from a manual transmission E46.

I found a couple threads, but no real answers. I finally decided to PM the almighty and infinitely knowledgeable Mr. Nick G @ Technique Tuning, who informed me that it is a direct swap, and he performs this swap on his steptronic cars with no problems.

The mechanical fan and the aux fan have both been removed on my car, and replaced with a single OEM electric fan. So far so good. No wiring, no fitment issues, nada. Plops right in, plugs right in, and works.

Part # 17-11-7-561-757-M14
Cheapest place to buy: Pelican Parts - Click for direct link
Price: $253.00
Why?: Because a good aftermarket electric fan costs $150+. This is $100 more, and it's a direct plug-n-play.


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#418 ·
just an update for you peeps.

Having completed my first aussie summer since the install I can say that removing the AUX fan is of no concern. I live just out of Brisbane and we experienced a week of days over 40C and a coupe as high as 44. Add to that humidity in the range of 85percent with a temp of 35 for a week either side of it and I say that's pretty good

even with x5 e53 19s on the old girl and 265oookm on the clock she is now down to just 8.9L per hundred predominantly highway driving. Prior to this the car had been 9.2 since I got it at 200oookm
 
#420 ·
Part number is 17117561757 and it will fit

You can find more information in my thread below and at the end is a post with the best places to get the fan from

http://e46fanatics.com/forum/showthread.php?t=849735

Make sure that your transmission fluid has been replaced and that the auto trans thermostat in the expansion tank is good.
 
#421 ·
Part number is 17117561757 and it will fit

You can find more information in my thread below and at the end is a post with the best places to get the fan from

http://e46fanatics.com/forum/showthread.php?t=849735

Make sure that your transmission fluid has been replaced and that the auto trans thermostat in the expansion tank is good.
 
#429 ·
Living down in AZ, few weeks ago it was 115F ambient, and the single Behr Hella fan kept my car at 96C idle, 99C cruising. I'd say it's doing its job just fine :thumbsup:
 
#423 ·
I got the Behr fan when I didn't my Mechanical Fan delete. It was on the car for two years before I sold it. Worked great.
 
#431 · (Edited)
So this little box on the fan isn't connected how do I connect it in this conversion , I have a 1999 BMW 323i
With the auxiliary fan in front of the radiator removed, you'll use the same plug to power the new electric fan behind the radiator.

Edit: Or are you referring to the AUC sensor? AUC sensor has four wires (two brown, one blue, and one yellow) and is circled in red below:

 
#436 ·
I am in the process of this swap as well as some other repairs. One question I have that I did not see a clear answer to in the 44 pages of this thread. Do I put this shroud back on or not? I don't know if airflow through the radiator would be better with or without it.
 

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#440 ·
Sounds like it's out of balance.

I've seen some fans come with a little clip attached to one of the blades. Did you happen to remove that during installation by mistake?
 
#441 ·
Sounds like it's out of balance.



I've seen some fans come with a little clip attached to one of the blades. Did you happen to remove that during installation by mistake?

I was thinking out of balance as well.. Took the fan out today to check it and everything "looked" ok. Going to call ECS Tuning tomorrow.. Maybe they will help me out since it is only a couple months old..
 
#444 ·
wanting to do this, but first would like to know the pros and cons, thanks yall!!
Search is a useful function on this site. But off the top of my head, in no particular order ...
  • Removing the fan and fan clutch off the engine reduces weight that the engine has to spin around, and removes the fan clutch, which can fail
  • The engine mounted fan has been known to self destruct, sending blade(s) into the radiator, hood, sometimes due to bad engine mounts.
  • Removing the auxiliary front mounted fan opens up direct airflow to the radiator (recommend covering the front of the radiator with black aluminum screen door mesh, to keep bugs and crud from clogging the radiator fins)
  • Removal helps with access to the engine
  • The replacement electric fan uses the same connectors to the engine computer as the front mounted fan, so no other mods are needed for this to work
  • I have a Bosch fan, and another choice is Behr, also OEM. You don't have to buy BMW, however, I also wouldn't get the cheapest no-name I could find.
 
#445 ·
Thank you for all the info!!:thumbup: another quick question i have is does the electrical fan emit as much coolness(fan speed) and does it run right when you turn car on like the mechanical fan?(and stay on) is the aux fan the one closess to the bumper and when does that run? and its purpose?
 
#448 ·
There is only one ECU controlled fan in the e46. Either the one in front of the bumper on auto transmission or the one next to the engine with manual transmission. There are 4 inputs that determine when the electrical fan is turned on (I've posted those a few times). As solidjake said, this has been done many times, and I don't recall anyone, especially in Florida, Nevada, and Southern California reporting any issues due to the conversion.
 
#450 ·
... I dont want to remove aux fan how do i do the delete?
When you replace the mechanical fan with the electric fan, you unplug the aux fan in front of the bumper, in order to plug in the new electric fan behind the radiator. If you don't want to remove the aux fan, it will just stay there, blocking direct flow air to the radiator.
 
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