FYI: Mechanical Fan to Electric Fan Swap

This just happened to me on my Z3. While attempting to change the thermostat, I turned on the car, and the fan exploded. Luckily for me, the hood was up so a blade ended up taking out just a grill (and my radiator and belts :roll eye )

So now I'm looking for a conversion to a electric fan. I've seen people remove all the fan (aux and clutch) and run a powerful SPAL puller fan on the factory Aux harness.

Originally Posted by Iceman00

This just happened to me on my Z3. While attempting to change the thermostat, I turned on the car, and the fan exploded. Luckily for me, the hood was up so a blade ended up taking out just a grill (and my radiator and belts :roll eye )

So now I'm looking for a conversion to a electric fan. I've seen people remove all the fan (aux and clutch) and run a powerful SPAL puller fan on the factory Aux harness.

Did you even read what I wrote?

Nice write up. Another route is this guy, he makes good controllers for using "other" electric fans:

http://www.dccontrol.com/index.htm

$80 for controller and $40 for a used 3.8 Taurus fan. I've been researching this for a friend because I didn't think our fans were plug and play. Nice find.

I want to do this conversion, but have to take out the mechanical fan with the auto tranny - a PITA. Just wait for the next time when doing the cooling system work.

Originally Posted by jzwu

I want to do this conversion, but have to take out the mechanical fan with the auto tranny - a PITA. Just wait for the next time when doing the cooling system work.

Adjustable Wrench + Rubber Mallet = Comes right off.

Originally Posted by kpeng

Adjustable Wrench + Rubber Mallet = Comes right off.

Not for me

This is great news to me. Thank you. But can I just ask 2 things?

If you can just use an electric fan on an auto model, what was the point of them making a mechanical fan version? Just to sell more due to the consumers lack of knowledge?

Also what did you use to plug the hole up where the mechanical fan screwed into? Or you just left it open like that?

Originally Posted by EmFiftyFour

Not for me

This is great news to me. Thank you. But can I just ask 2 things?

If you can just use an electric fan on an auto model, what was the point of them making a mechanical fan version? Just to sell more due to the consumers lack of knowledge?

Also what did you use to plug the hole up where the mechanical fan screwed into? Or you just left it open like that?

1. Could not tell you. BMW gets rid of parts all the time. Some E36 M3s came with aluminum doors for no reason. Some non-lux package E36 M3s came with lux package seats on the M3 instead of vaders for no reason. They just get rid of crap.

2. I just left it open. Turner Motorsports sells a cap for it if you must.

Ok you need to clarify as I am in the process. Heres the issue, my car has BOTH aux fan and mechanical fan. Im taking out the mechanical fan just becuase the blades are broken and cost of replacment equals new electric fan.

Putting in the new electric fan is easy as pie, but where do you plug it into? I beleive the spot you plugged yours into is where the AUX fan used to plug into, well i still go minez. Or do you think im safe just taking out the mechanical fan and relaying on the AUX fan?



(Reason why I dont want to only use my AUX fan is becuase BMW put in a mechanical fan for a reason, extra cooling is clearly intended. If the aux fan could have handled it, they wouldnt have added the mechanical fan)



Sorry for the chicken scratch, but Im in a mess here.

Originally Posted by 323iINt.o

Ok you need to clarify as I am in the process. Heres the issue, my car has BOTH aux fan and mechanical fan. Im taking out the mechanical fan just becuase the blades are broken and cost of replacment equals new electric fan.

Putting in the new electric fan is easy as pie, but where do you plug it into? I beleive the spot you plugged yours into is where the AUX fan used to plug into, well i still go minez. Or do you think im safe just taking out the mechanical fan and relaying on the AUX fan?



(Reason why I dont want to only use my AUX fan is becuase BMW put in a mechanical fan for a reason, extra cooling is clearly intended. If the aux fan could have handled it, they wouldnt have added the mechanical fan)



Sorry for the chicken scratch, but Im in a mess here.

The Aux fan itself is not strong enough to cool the car. If you removed both and replaced it with the electric fan (like I did), it will be cool enough.

Originally Posted by kpeng

1. Could not tell you. BMW gets rid of parts all the time. Some E36 M3s came with aluminum doors for no reason. Some non-lux package E36 M3s came with lux package seats on the M3 instead of vaders for no reason. They just get rid of crap.

2. I just left it open. Turner Motorsports sells a cap for it if you must.

Good to know thanks. I can't believe they would make a mechanical fan if they didn't have to. Maybe cheaper for them to produce?

Originally Posted by EmFiftyFour

Good to know thanks. I can't believe they would make a mechanical fan if they didn't have to. Maybe cheaper for them to produce?

What you have to understand is cars are used in all kinds of different climates. They used a mechanical fan in autos because they probably thought that, although it was overkill for someone living in Wisconsin, it would barely keep up on a 120 degree day in the arizona desert. Also what needs to be taken into consideration is that fan isnt only helping cool your engine, its also cooling your auto tranny, which runs at higher temps... this is what is scary.

I've got an auto and I've ran no mechanical fan with no electric fan (just the puller fan in front of the car) in the Texas summer on 105 degree+ days, and have had no engine overheating for almost a year now without my mech. fan. Whether it be stop and go, highway, or idle, I never had a problem... I'm not worried about my engine, its my tranny that I'm worried about. The reason kpeng had a prob is because he's boooosted.

But I'm so glad someone fiiiinally decided to just hook up an oem electric fan to see if it worked, I cant believe it took us this long to figure it out! lol

Originally Posted by kpeng

The Aux fan itself is not strong enough to cool the car. If you removed both and replaced it with the electric fan (like I did), it will be cool enough.

OK SOO, you did plug the electric fan into where the AUX fan used to plugged into?

Originally Posted by 323iINt.o

OK SOO, you did plug the electric fan into where the AUX fan used to plugged into?

Yes

I wonder why bmw did just put electric fan on all cars. Nice write up kpeng, im sure its gonna help a lot of people who are thinking about doing this.

Originally Posted by kpeng

Did you even read what I wrote?

Did you read the post before mine?

Hmm, intruiging. Don't mean to sound like a noob, but how would it cool the tranny better then an electric one?

Originally Posted by alibusoul

What you have to understand is cars are used in all kinds of different climates. They used a mechanical fan in autos because they probably thought that, although it was overkill for someone living in Wisconsin, it would barely keep up on a 120 degree day in the arizona desert. Also what needs to be taken into consideration is that fan isnt only helping cool your engine, its also cooling your auto tranny, which runs at higher temps... this is what is scary.

I've got an auto and I've ran no mechanical fan with no electric fan (just the puller fan in front of the car) in the Texas summer on 105 degree+ days, and have had no engine overheating for almost a year now without my mech. fan. Whether it be stop and go, highway, or idle, I never had a problem... I'm not worried about my engine, its my tranny that I'm worried about. The reason kpeng had a prob is because he's boooosted.

But I'm so glad someone fiiiinally decided to just hook up an oem electric fan to see if it worked, I cant believe it took us this long to figure it out! lol

Although the OP post is somewhat interesting it is severely flawed and frankly ill advised.

1) Removing the AUX fan just so he can install the intercooler is a mistake at the expense of his tranny. The AUX fan on the automatic transmission is design to kick in when the clutch fan is insufficient at keeping the engine in the normal operating temperature.
When your engine temperature is in the middle it reads between 167°-235.4° F. There is about a 68 degree variation between what is normal. Anyhow, when the OP engine was overheating, he was overstressing both his engine and transmission because it means that the temperature was above 235.4F. Since the automatic transmission used the engine coolant to cool down (via the tranny heat exchanger), this means that the OP's tranny was being over stressed. Any temperature above 200F will decrease the tranny lifespan and I am sure the OP just decreased his tranny life. His tranny is going to die soon.

2) The reason why BMW only install a clutch fan (ie mechanical fan) on its automatic cars is because they want to keep the tranny in its optimum operating temperature. The clutch fan is working to keep the coolant below 200 degrees so that the auto tranny doesn't get overheated. Manual transmission doesn't have a cooler and does not rely on the engine coolant to cool itself so therefore they don't require a clutch fan.

am i correct in thinking that you guys are putting in an electric fan because the cost of a mechnical fan is expensive?

My fan was broke to bits... a replacement was £21......

??

Originally Posted by ///Flash

Although the OP post is somewhat interesting it is severely flawed and frankly ill advised.

1) Removing the AUX fan just so he can install the intercooler is a mistake at the expense of his tranny. The AUX fan on the automatic transmission is design to kick in when the clutch fan is insufficient at keeping the engine in the normal operating temperature.
When your engine temperature is in the middle it reads between 167°-235.4° F. There is about a 68 degree variation between what is normal. Anyhow, when the OP engine was overheating, he was overstressing both his engine and transmission because it means that the temperature was above 235.4F. Since the automatic transmission used the engine coolant to cool down (via the tranny heat exchanger), this means that the OP's tranny was being over stressed. Any temperature above 200F will decrease the tranny lifespan and I am sure the OP just decreased his tranny life. His tranny is going to die soon.

2) The reason why BMW only install a clutch fan (ie mechanical fan) on its automatic cars is because they want to keep the tranny in its optimum operating temperature. The clutch fan is working to keep the coolant below 200 degrees so that the auto tranny doesn't get overheated. Manual transmission doesn't have a cooler and does not rely on the engine coolant to cool itself so therefore they don't require a clutch fan.

This is the main reason, why I'm worried about going to a electric fan. Everything he posted there makes sense to me.

I don't wanna shorten the life of my slushbox even more

The coolent temp is the same no matter what type of fan you use to pull air accross the rad. the car was over heating. now its not. there is an intercooler. clutch fans are for fags. the end.