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electric fan problems

4K views 43 replies 10 participants last post by  NEW INTERIORS 
#1 ·
I have installed a electric fan on my 327 with a new aluminum radiator, the fan has a temp probe installed in radiator to find temp, but I found when the fan comes on it is blowing air out from the engine bay instead of pulling air from the outside. Do I need to reverse some wires or something? I drove the car and it cools okay but common sense will tell you when operating the chevelle if fan is pushing and the car pulling the air in from the outside seems both would cancel each other out. It didn't say anything in the directions, do you guys have some insite with this problem? Thanks
 
#2 ·
If there are (2) wires going into the motor they can be swapped and the fan will run the other direction.
Some fans have only (1) wire. The housing is ground and wire is +. These cannot be changed electrically. Possibly the motor position can be flipped or the fan blade flipped to blow the opposite direction.

vicrod
 
#3 ·
electrical fan problems

Thanks for this insite, I do believe there is only two wires - & + from the fan and more from it's relay box, fan is mounted on the radiator so I guess I will try flipping the fan blade to change the air flow to pull instead of push. Not sure if this fan blade can be changed or not for reversal, I will check. I do believe fan has a plastic cap over it's shaft. I have only worked on the old water pump fans, this is all new to me. But I will have to get new disc zip ties to remount the fan. Others will have to be cut to release, I think they are a one time deal when used.
 
#4 ·
if the fan came as a "pusher" new, and you installed it as a "puller" (which is what you want) then you will need to flip the blade and reverse your polarity. this will then pull the air through the radiator. you really should build some brackets for your mounts and not use the zip ties.
 
#5 ·
Electrical fan problems

Thanks Dr.
I feel stupid now I bought a pusher new and needed a puller, I am such an idot. And those zip tie things came with this fan for mounting but I agree I need to figure out some other way to include a shroud and mounting brackets would be much better and more efficent.
 
#11 · (Edited)
DOCTOR DC said:
only reverse your polarity and see much air it moves. NONE
Man!!!! You have to be joking or something.. :D
Sorry but that is not true... :nono: I have been doing it for years... There is very little to no difference at all.. :D



Now I do have to say, there can be two answers for this... There is some fans you have to flip the blade,, But there is some that you can't flip the blades, But can run them in reverse..The ones I buy, all I ever had to do was reverse the polarity.. And I have done this on Hot big block chevy Motors.. AND DIDN'T RUN HOT...
 
#12 ·
Why wouldn't you run them on the front side? Many OEM cars run them that way..... Blockage of air? it has the same mass weather in front or rear, the only bad thing I can see is if you removed the stand off and mounted it right up against the fins and then it would be the same front or rear. I have run one in the front on two different vehicles with zero problems.

Reverseing the wire will in most cases cause the fan to run in the other direction.
 
#13 ·
EOD Guy said:
Why wouldn't you run them on the front side? Many OEM cars run them that way..... Blockage of air? it has the same mass weather in front or rear, the only bad thing I can see is if you removed the stand off and mounted it right up against the fins and then it would be the same front or rear. I have run one in the front on two different vehicles with zero problems.

Reverseing the wire will in most cases cause the fan to run in the other direction.



It will work in front, But it does restrict the air flow some.. If you run a really hot big block,, Mount it on the front, And then mount it on the back,, YOU WILL SEE THE DIFFERENCE.. ;)
 
#15 ·
It is easier for the fan to pull air acrossed the radiator fins than it is to push it acrossed. If you are pushing the limits of the cooling system size with high hp engine, mounting the fan in front will have less effect than mounting it behind the radiator. Common knowledge with the 20's-40's street rod crowd with their narrow front ends.

True of all fans, easier to pull air out a window creating a vacuum through a room than it is to try to push air in from a window. A house will cool a lot faster in the evening with a fan blowing out, pulling cool air in from open windows in the other end of the house. Works the same in cars
 
#17 ·
EOD Guy said:
sometimes you don't have room for it where it's supposed to go or as the OP stated .... he got the wrong fan etc.... and it works just fine pushing thru the radiator.

Well with all the years I have been doing cars, :drunk: I have to say: I have ''NEVER'' seen a chevelle That ''HAD'' to run a elec fan In front of the rad because of no room.. :mwink: Look I'm not gone to keep bumping head with you.. I do know the difference by now, what will work, AND WHAT WILL WORK BETTER.. Man!!!! some people just don't get it.. :drunk: :drunk: :drunk: Good night.. :welcome:
 
#19 · (Edited)
EOD Guy said:
as the OP stated .... he got the wrong fan etc.... and it works just fine pushing thru the radiator.

Thats the key word here,, It works just find,, :mwink: And I Posted a better way for it to work for him,, :D

chevyrally68 said:
I drove the car and it cools okay
And Here he said It cool's Okay... Not just find.. There is a difference Between okay and just find.. You should know that.. :mwink:

Sorry!!! but on a car that can be worth $20 or $30,000.. I don't think he want's just OKAY !!! :nono:

Or ''HE WOULDN'T BE ASKING FOR HELP''.. :D


EOD Guy said:
Then don't! Just because it's not your way, doesn't mean it's wrong! And with all your years of experience etc..... you should know that by now.

It has ''NOTHING'' to do with my way.. :mwink: And your right I do know.. :D

But I ''WILL'' let him know WHAT'S BEST !!! :mwink: He can do what he likes, Its his car.. But When you come here asking a question,, I will give him the Best answer I can...You try in have a good day now.. :welcome:
 
#23 ·
I haven't built as many cars as you all have but for what it's worth, my understanding is that if the fan has curved blades you need to flip it so the blade tips are trailing.
If your fan has straight blades it is less important to flip the blade, unless they have a definite airfoil shape, then the thicker edge should lead for optimum performance. If the blades are straight and flat, there is probably no advantage to flipping the blade over.

Hope this helps.... :thumbup:
 
#24 ·
Hey Fellas,
It is all good everyone has good advice and I appreciate all your opinions. I only have two wires coming from the fan itself one black(ground)
and one blue(positive) and more from the little box mounted on the fender. I am not sure if there is a way to reverse this dam fan to make it change polarity? But I am going to call the shop where I bought it to see if it only a pusher. Otherwise I guess I might have to start over with a new fan, maybe go with a twin puller fan set up. But I hate to wiring this darn thing again, wiring is not friend, I should of checked this before, dam it!
 
#25 ·
chevyrally68 said:
I only have two wires coming from the fan itself one black(ground)
and one blue(positive) and more from the little box mounted on the fender. I am not sure if there is a way to reverse this dam fan to make it change polarity?
All you need to do is reverse the two wires to the fan. Power to the black wire and ground the blue.
:thumbup:
 
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