electric fan blow air or suck

[paaw]

do the fan suppose to blow air through radiator or suck air got the dual fans off of a nissiam altima and trying to make sure hooked up right, mine are sucking air through radiator

[SactoJim]

Ideally they should pull air from the front of the truck towards the back. Fans mounted engine side of the radiator.

[shifty]

And stock fans vary from vehicle to vehicle - some pull, some push.

Sometimes you can simply reverse the flow of the air by reversing the + and - wires (reverse polarity). It all depends on whether the fan will operate that way - most fans you buy at Summit and Jegs are reversible.

[piecesparts]

If you go to ANY fan supplier's site and look there are both kinds. The most effieicent are the ones that PULL air through the radiator. Pusher fans are usually used as a supplemental cooling fan for vehicles that tend to overheat. I have dual fans on all of my vehicles and they are all pull type fans and are mounted behind the radiator in the engine compartment.

If you are blending a fan from another vehicle to a radiator that is stock and possibly an older style copper unit, then there may be a chance that you do not cool as well as you would like to. The majority of later model cars are using aluminum finned radiators to get the extra heat transfer that is available with that material.

[paaw]

well mine are sucking and I have a low and high speed on both fans so I think the will pull pretty good I think I can run both on low when drivin, and use high with the ac on, when I get it hooked back up, will test later on today

[mnunn454]

Suggest mounting on the outside [forward] of the radiator and wire them so they're "pushing" the air into the radiator toward the engine (front to back).

On the average they're about 10% or more, more efficient if set up this way.

[Sammy]

If you pushed the air into the rad would you still use a shroud behind the rad? I am not doing this but interested in this thread.

[paaw]

Fans worked great could feel them pulling the cool air in while it was idling in the yard, drove about 30 miles temp hand never made it half way. Didn't even have to turn on high, also installed headlight relay now I have to gptry them out tomorrow

[onetonk5]

If your trying to use a pusher fan a good portion of the blown air is deflected by the tubes and fins on the rad. My radiator guy always suggests a puller fan.

[GREASEMONKEY72]

nice to hear that your fans are working nicely

puller fans are better since you have the air being pulled through the rad and pushed over the engine, if needed for extra cooling on hot days or hauling a trailer or whatnot you can add a second fan centered on the front of the rad to flip on when/if needed to push extra air over the fins

[GREASEMONKEY72]

what year altima did you pull them out of? v6 or 4banger?

[piecesparts]

Everyone has an opinion and here is mine. I got it from the discussions that I had with first the "Flexilite" people and second the people from "Be-Cool". You meet some really great people on a Hotrod Power Tour. The pusher fans provide two downfalls--1st) they restrict air flow by being on the front of the radiator. 2nd) they are somewhat inefficient on the fact that in most cases they are up against the radiator and they push air in only the small area that they cover and a lot of that is diffused against the fins and dissapated on the outside of the radiaotr rather than going through it.
The puller fans if mounted right will move more air, give a better flow through the core fins, and provide a better movement of air in the engine compartment. Now comes the decision on what fan to get. There are a lot of them out there on the market and some move some great amounts of air and some are just there to take your money. If you are driving on the highway, then in most cases any fan will do, but if you are going to load up the truck and work in a hot city, then a better grade of fan is needed. I finally settled on the dual 11" fans from SPAL because each fan is rated to move around 2800 CFM of air against a dynamic load. (Dynamic is something such as an engine compartment that has other thnigs happening rather than just an open space). A lot of fans ar tested in a "Static" conditon which is to measure the air flow across from point 'A' to point 'B' which has no backpressure in it. The sales people will tell you that their fan is limited to certain levels of Horsepower With or without A/C on. SPAL dosen't do that. I am running my fans in two different trucks and I can run on a really hot day and have no problems with them. They sound like gas turbine engines up front, but it works well. My setups are designed to run one fan at slow speed, then speed up as the temp goes up, and finally the second fan starts if it is really hot or the A/C is on. I have not gotten to the second fan point yet. I recommend some phone calls to Be-Cool and Flexilite and then do comparisons before doing a lot of work and then just bolting something on. I have seen a lot of really nice Streetrods sitting on the side of the road with water boiling out of them. Imagine putting $5000 in a motor and putting a $19.95 fan on the radiator. NOT ME.

[paaw]

I think that they off a maxium instead about a 90-94 the box style the fans are in a one piece deal with four wires going to each fan a green, blue black and yellow, yellow and black are ground blue and green are hot. blue or green hooked up make it run on low both have to have hot to them to make it run on high, so I put two switches under my dash on for low, other for high

[nvrforgotten52]

if you have a pusher and its on when your driving down the road it seems like to me that it would counteract the air blowing in from the grille... i have electric fan set to pull... it just makes sense that way because it pulls the cool air from outside and not the warm air from your engine...

[piecesparts]

Originally Posted by nvrforgotten52

if you have a pusher and its on when your driving down the road it seems like to me that it would counteract the air blowing in from the grille... i have electric fan set to pull... it just makes sense that way because it pulls the cool air from outside and not the warm air from your engine...

Think about this a little different. If the fan is outside and running it would be pushing air into the radiator. It would not go against the air flow from in front of the grille but actually enhance the airflow into the engine compartment. The puller fan is pulling the air into the radiator from the back side of the radiator and then discharging it into the engine compartment, so that is your puller type fan. At no time do you pull air from inside the engine compartment and send it through the radiator and out towards the grille. There are some heavy construction equipment pieces that actually reverse the airflow for the winter, but that is a different story.

The pusher fan is usually less effective, because of where it mounts and the way it limits a full flow of air into the radiator core.