Author Topic: Electric fan mod (Read 15172 times)

tjts1 · « **Reply #15 on:** December 02, 2007, 11:49:00 PM »

dude8383
From what I can tell from your pics, you have the fan running directly off the temp switch which isn't ideal and potentially dangerous. The temp switch on the side of the radiator should be used to activate a relay which activates the fan. Its hard to describe in words. My suggestion would be have someone look at the car that has some electrical experience.

Quote from: George77;38781

It's not that fan a bit bigger ?And olso eats to much power and it's also too heavy ,much heavyer then your thermal clutch.From what I Know the plug for the fan it in left side somewere under de hi beam and behind the plastic cover,I mean in engine bay,and the colour are:brown =negative,Blue with black first speed and the third one it second speed

http://www.m42club.com/forums/showpost.php?p=27468&postcount=84

Quote from: teamgtnfx01;38754

lets see come pictures of that valve cover and the manifold i wanna do taht how did u get the stripes was it hard

Are you drunk?
http://www.m42club.com/forums/showpost.php?p=27243&postcount=78

George77 · « **Reply #16 on:** December 03, 2007, 06:45:33 PM »

Now I see ,Why didn't you used the car's electrical functions,you have everything you need,Relay for both speeds and you used that volvo relay?.I know very well that fan because even if I am a 200% BMW guy where I work ,80% I'm repairing Volvo's.

George77 · « **Reply #17 on:** December 03, 2007, 06:57:43 PM »

Sorry ,now I read everything and I saw that you actually used the car's wires and relay.

tjts1 · « **Reply #18 on:** December 03, 2007, 07:05:11 PM »

The only reason I picked this fan is because I'm familiar with it. We have 3 Volvos (240 now dead, 850 and 960) in the family. I did the same swap to the 240. But there are many other fans out there that will work just as well. They probably even have the appropriate size shroud. As you mentioned, the existing BMW relays and wiring are already perfectly adapted for this electric fan conversion. Once you have an electric main fan, the aux fan becomes dead weight.

George77 · « **Reply #19 on:** December 03, 2007, 09:10:44 PM »

You're right,but that way I asked if it's not too heavy, to not become a inertia weight.

D. Clay · « **Reply #20 on:** December 03, 2007, 11:53:06 PM »

If you have A/C you need to leave the aux fan in there. It comes on with the A/C clutch. Without it, if the radiator fan isn't on, the A/C head pressure will build up. There's a high pressure shut off in the A/C system but it's still not good for it. It will gradually weaken the seals in the compressor and shorten it's life. If you don't have A/C - no problem. If you do it will not blow as cold as it should in addition to the possible damage. The A/c needs even more air than the OEM fan provides to achieve maximum cooling. As I mentioned, that's my reason for putting in an electric fan and modifying the aux fan to run on high with the A/C.

tjts1 · « **Reply #21 on:** December 04, 2007, 12:24:04 AM »

All your concerns about the AC system are legitimate but thats the beauty of this conversion. The new puller fan does the same job as the AUX fan. Because its running off the existing relays which are still connected to the AC system, the puller fan activates with the AC system as well as the temp sensor in the radiator.

gearheadE30 · « **Reply #22 on:** December 04, 2007, 04:08:10 PM »

The only problem is that the fan is not pulling (or in the case of stock, pushing) air directly through the condenser. The air will want to come in through the path of least resistance, which isn't through that radiator. Does it put too much strain on the system to wire the aux fan in parallel to the high-speed wiring of the electric main fan? If it is difficult to get the aux fan out, then might as well use it for something.

tjts1 · « **Reply #23 on:** December 04, 2007, 04:28:59 PM »

Quote from: gearheadE30;38900

The only problem is that the fan is not pulling (or in the case of stock, pushing) air directly through the condenser. The air will want to come in through the path of least resistance, which isn't through that radiator. Does it put too much strain on the system to wire the aux fan in parallel to the high-speed wiring of the electric main fan? If it is difficult to get the aux fan out, then might as well use it for something.

I don't know what other path the air would take other than through the condenser. Whether you push or pull the air, it doesn't matter. Having the aux fan in front of the radiator reduces the effective surface area of the condenser and radiator. I don't see any advantage to this.
The volvo fan uses a 30a peak on high speed. Not sure how much the aux fan uses but its probably in the are of 15-20a. So when you have both fans going on, you will need a 50a relay and fuse and probably replace all the wiring with something thicker. 12 or 10 gauge. I don't think its worth it. The electric puller fan more than does the job of both the aux fan and the clutch fan.
The aux fan is a pain in the ass to remove. The two options ar either remove the bumper or remove the radiator and condenser. I used some chain cutters to make minced meat out of it and remove it through the grill.

gearheadE30 · « **Reply #24 on:** December 23, 2007, 09:33:54 PM »

I finally got the swap done, took me all day to finish the shroud, wire it, and do some other assorted stuff. So far, it works great. After wiring everything to use the original connectors, I discovered that the fan was spinning backwards. took a half hour to discover that the plug can be installed 2 different ways. Spun the plug around, and it works great. There are no vibrations when it is running and you can't even hear it from inside the car. Havn't gotten the aux fan out yet, but I need to remove the valence to bend it back into shape and repaint it. Havn't driven it yet because my parents parked in front of the garage

. It looks pretty stock from the driver's side, but there is some sheet metal and bracketry on the passenger side that gives it away. Hopefully I'll be able to get pics and a driving impression up tommorrow.

tjts1 · « **Reply #25 on:** December 23, 2007, 10:02:09 PM »

Excellent! Did you use the E36 temp switch?
Removing the aux fan is a pain. Have fun.

gearheadE30 · « **Reply #26 on:** December 24, 2007, 09:07:41 AM »

Yes, I used the e36 switch. That was the easiest part of the whole project!

Anyway, here are some pics:

I just soldered the new wires onto the old plug to keep the factory wiring and locations:

Notice how close the fan is to the water pump shaft. Make sure you measure this before you put it all together. The engine doesn't really move forewards or backwareds, just side to side. I ended up having to offset the fan so the rear bearing carrier for the motor was above the pump shaft.

Heres the done deal. All of the wiring on the passenger side is coiled under the balck cover behind the headlights now, so it looks a bit nicer.

tjts1 · « **Reply #27 on:** December 24, 2007, 10:07:43 AM »

The 850 shroud looks to be a bit thicker than the 940/960.
http://farm3.static.flickr.com/2118/2133648058_3cce69077d_o.jpg
Your auxiliary fan looks completely different from my old one.

gearheadE30 · « **Reply #28 on:** December 24, 2007, 10:30:51 AM »

Yes, it is thicker. i got it for $10 though, so I figured I could always get the other shroud later if this one didn't work.

I think my aux fan is stock, although the plug has a little bit of damage from being removed at some point in the past. I guess it may have been changed. The car came from Cali, so the fan was probably running all the time.

tjts1 · « **Reply #29 on:** December 24, 2007, 11:36:34 AM »

Mine had 5 paddle like blades and a cast iron frame. This is how it looked after i removed it with chain cutters.
http://farm3.static.flickr.com/2012/2133051277_d78db60693_o.jpg
Urs looks like it came out of an E36. It might be valuable on Ebay or somewhere.