Electric Fan - Push or Pull?

[Guest Anonymous]

Next weekend I will be helping a guy I know delete the belt driven fan and stock radiator and install his new 3-row re-core with an aftermarket electric fan. We've worked out all the relays and wiring and plan to mock up everything this weekend. The only remaining question is should the electric fan be mounted as a pusher or puller? Does it really matter either way or is it just preference? Also when mounting these electric aux. fans what type of spacing do you use between the actual fan and the core fo the rad?

Thanks

[BLUNT]

typically space and a/c dictates push or pull. some may have a preference but both work well. im running a pusher on my e30 because of space. i dont like the attaching kits that use plastic ties that go thru the radiator. i fabricated stainless mounting brackets that keep the fan a few mm off the radiator. stuff the biggest fan you can fit in there. i drive mine hard on the track and never have a cooling problem

[JsnPpp]

Hi,

Mounting the electric fan in front of the radiator, you want the fan to push the air through the radiator - in other words the air direction should be from the front of the car to the rear of the car.

If the direction is opposite, it will offset the affect of the natural air movement through the radiator while driving and you will likely overheat.

Don't worry, after it is installed just plug it in and see what direction the air is moving, reverse polarity if it is blowing out the front of the car.

I mounted my fan right up against the radiator - make it firm so that it won't vibrate or dig into the radiator blades themselves - they are fragile. Others may have comments on alternate methods.

Hope this helps!

Jason

[Guest Anonymous]

Blunt,

We picked up some alluminum stock at Home Depot and are planning on building some type of contraption to brace and bracket the fan without using those stupid plastic things. I guess we'll stick with the puller option because it will be easiest to access and run the wires but that presents more of a challenge with mounting location. What types of things can we do to brace the fan up against the radiator? What we are trying to avoid is having the fan rattle and bend the fins or be spaced far enough away from the radiator that air comes from the sides and scoops in rather than thru the fins of the rad itself. Now I'm thinking that maybe a pusher setup would be best because we could setup the brakets in a way that they would utilize the stock radiator mounting holes.

Is there an easier way to do this? The car has no A/C, it's a 75 daily driver, no real prize but a solid car. We don't want to drill any new holes but then again I feel like we're trying to re-invent the wheel and it's just a simple electric fan.

[JsnPpp]

Hi,

I chose the same route. I didn't want to drill new holes so I used the existing radiator mounting holes and screws and simply added small iron supports (flat steel with a hole on each end) that bridged the gap between the four radiator holes and the front mounted fan.

The bracket by nature pulls the fan close into the radiator and so eliminates wobble. I understand the desire to mount it slightly away from the radiator, it makes sense to eliminate any rubbing against the radiator itself. I am sure there is a way to add a rubber spacer of sorts however I chose not to do this on this particular car.

I am sure there are several ways - keep searching and also someone else may comment.

Hope this helps,

Jason

[Guest Anonymous]

To be honest this isn't my car and because I'm going to be building an 02 down the road it's a wonderful opportunity for some trial and error on my part. I don't think that my friend would exactly look at it the same way though.

I have heard that it is very important to mount the fan as close as possible to the radiator, hence the crappy plastic ties that come with it. I would be worried about this too because if we mount it about 1/4 to 1/2" away from the radiator wouldn't we just be pushing the air out the sides and not exactly thru the radiator? It's a little bigger issue because we will be removing the belt driven fan so if it dosen't work we - or he will be screwed and have to turn off the motor.

Do you guys bolt the brackets just in line, one bolt at the radiator screw and then one at the fan or is there more of a structure built? Is it sortof suspended between four pieces of flat stock similar to a web type of a setup? Wouldn't that allow the fan to move quiet a bit?

[swiftt]

Many later '02s and 320s, that came with AC, have an electric Aux fan already. It's mounted between the grill and radiator with brackets that bolt to the supports behind the grill. If you can find one, that will solve your reluctance to drill holes. You can also build a shroud if you're concerned with the air bleeding off to the sides of the radiator. A 30.00 Chinese brake from Harbor freight and some sheet metal will have you on your way.

Just curious, if the car is not a prize, why are you so reluctant to drill holes? If drilling holes gets the job done right, I'd be for drilling them wherever needed. Who in the world is going to notice some holes drilled behind the grill? My car is from SoCal with no rust and the original paint is still really nice. Solid as it is, I had no problem cutting 1.5 inches from the rad surround and welding up some capture nuts to mount a 320 radiator. Heck, I also cut up and altered the 4spd stuff so I could fit a 5spd. With all due respect to purists, it's just a car. ...And it's my car so I have no problem modifying it however I see fit. Megasquirt next!

I have two Aux Bosch fans if interested. One is 320 and the other is from an '02. The differences are very subtle and either would work.

Good luck with the conversion and have fun.

[SteveJ]

Mount it in front of the car and push it through.

It helps the life of the fan motor as there is cooler air rushing over it. A little bit, but it does help.

I had installed a used 320i fan. When that failed in rush hour traffic going into SF, I went to my local car parts place and told them I wanted GOOD electric fan. I ended up with a 14" or 15" Hayden unit that I wired into a manual switch. The thing sounded like a damn turbine.

I did use the plastic mounts that came with it. While they are not as robust as metal and I probably wouldn't use them on a racecar, they were fine for my daily driver/autocross car. I never had one of them fail.

[Lars]

Pic says it all. Almost. The fan case sits the fan blade far enough away from the radiator that you don't need to worry about it.

Yes, I used the crappy plastic things that go through the otherwise perfect 320 radiator, stupid me.

The fan is a 12" Imperial, which I believe was sourced from Hayden since that is what is on the plastic mounts.

In order to make it a pusher I had to flip the blade over. I have it controlled by an adjustable thermoswitch which turns the fan on when the temp gauge gets half way. I usually only runs when I'm below 30 mph, ok, so I admit I can't hear it at the higher speeds because the exhaust is so loud.

In short, it works well and was only $70. (Did I pay my brother back for it)

[ingraham]

there isn't room for a puller between the radiator and the water pump. ... unless you're retrofitting an external electric water pump.

Your aversion to the plastic mounting ties is valid. The fan manufacturers supply those because they are an easy, cheap, universal solution to the problem. Since you are willing to fabricate brackets, there is no reason to use the plastic radiator spears. Think about a minimal strap or angle piece that runs the full width left to right. Don't worry about a small gap between the fan and the radiator.