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I installed an electric fan and now it runs hotter!?!?

Discussion in 'The Hokey Ass Message Board' started by CadillacKid, May 21, 2013.

  1. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?

    Nope, as a matter of fact, if I HAD to run an electric fan I would look at OEM stuff. But they are ugly as sin!!! And, all the manufacturers went to electric fans BECAUSE they went away from the normal engine mounting standards to transverse mounting making a real fan and shroud impossible. At best it was a band aid to fix that mess. I'm just saying that if you expect a 200.00 aftermarket fan to last like an OEM electric fan, don't. It ain't gonna happen, it won't work as well as a mechnical in our applications because it can't.
  2. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?

    Sounds a bit self serving to agree with you on this, but yes!! A hood with a 100 or more louvers correctly placed and puched can easily add up to about 15-20 degrees off a temp gauge in the right circumstances.
  3. S_Mazza
    Joined: Apr 27, 2011
    Posts: 363


    I agree with you, mostly.

    One thing I don't get is that if you browse Summit or something like that, the universal kits cost about as much (if not significantly more) than an OEM electric fan. But the universal kits generally top out at about 2,400 CFM for a single fan. A stock Ford Taurus fan moves about 2,400 CFM ... on low. On high, it moves 4,000 - 5,000 CFM. That's some real airflow. The thing pulls like over 40 amps. And you can buy this thing new (Dorman aftermarket) for under $100, with its own shroud. Or in the junkyard (pure OEM) for $50.

    Transverse engines are sure to be responsible for some part of the swap. But even RWD cars have electric fans these days, when they could have mechanical ones.

    The plastic OEM shrouds look out of place on a traditional car, for sure. But you could fabricate your own from sheet metal if you wanted to.

    A good mechanical fan ... nothing wrong with that! But I like electrics too, as long as they are the right ones.

    My real point is that people are so quick to blame certain parts when they obviously work great ... in the right system. I think the overall vision of the system is lacking. Everything from the firewall forward plays some role in keeping the car cool. If it's designed well, you don't need monster parts to keep a car from overheating.
  4. falconsprint63
    Joined: May 17, 2007
    Posts: 2,359

    from Mayberry

    I feel your pain. I've got the same issues and they've worsened after swapping tranny's over the winter which stumps me (I'm running a mildly built 390 with t-5). I'm going to go back to your OP. what is "runs crappy" or however you worded it? Mine is doing the same thing. I have a mechanical fan and an electric pusher. but when it gets to 210 there's a definate change in how it runs and it tends to deisel when shutting it off. from what I understand these motors are notorious for running hot if the timing is off even just a little. I suspect based on all the symptoms this may be part of my problem, and it may well be part of yours too. food for thought. I'm watching this thread
  5. CadillacKid
    Joined: Oct 15, 2002
    Posts: 1,507


    I'm gonna probably try going to a 160 stat and switching back to the mechanical fan's a 6 blade flex fan with that hokey shroud I've got...we'll see if it makes a difference...
  6. Hoptup Jalop
    Joined: Sep 29, 2004
    Posts: 1,118

    Hoptup Jalop

    51 Chevy 350/350 stock rebuilt rad 6lb cap 185 stat 7 blade flex fan no shroud no hood.. Runs great! Put hood on and heats up real bad..... Made a custom fiberglass fan shroud and will hold a shop rag on the rad and get to about 210 on a real hot day.... Think my problem is solved....Airflow!!!!

    Posted from the TJJ App for iPhone & iPad
  7. DrJ
    Joined: Mar 3, 2001
    Posts: 9,418


    A 160º thermostat won't do shit because your problem is already hotter than that!
    Did you move your distributor vacuum advance to full manifold vacuum yet?
    Engines overheat if their timing is retarded.
    If you are ok on the temp at highway speed (high RPM) but overheat in traffic (LOW RPM) you need more advance at low RPM.
    Manifold vacuum gives you that, so DO IT!
  8. You stated it's a four core radiator. Remember the thicker radiator the more air you have to pull or push through it. About the louvers in the hood,if the engine compartment is cramped and the hot air coming through the radiator can't get out of engine compartment fast enough then the outside cool air can't get in.
  9. 340HilbornDuster
    Joined: Nov 14, 2011
    Posts: 1,950


    I Bought an electric fan for my Duster...needed a low profile motor to fit between the radiator and water pump.
    Started running Hot!

    Most electric fans pull around 1-2 Horse Power.
    The metal fans pull almost 10 HP at full flow...maybe they're not as efficient but they defenetly move more air.
    I Put the mechanical fan back without a shroud and no more cooling problems!

    My 10c
  10. did you have the stock fan on backwards?
  11. Brad54
    Joined: Apr 15, 2004
    Posts: 6,015

    from Atl Ga

    Most new pick-up trucks use electric fans, and I haven't seen too many of them with front wheel drive configurations.

    Look at cop cars--V8, RWD, and they sit and idle all day long in the summer. Electric fan, good shroud, aluminum radiator, and the fans don't fail.

    They help meet the MPG standards, whilw a mechanical fan, even a good-working clutch fan, is still a draw on the engine.

    If I was going to go with an electric fan, it'd be an OE piece--they don't fail, and they move enough air to let the thing idle on a hot summer day, for hours on end. When is the last time you saw a new Corvette overheat in a traffic jam? If there's a tighter engine compartment, I haven't seen it. Hell, they're even sealed around the perimeter and have a big plastic engine cover on them to hold in the heat!

    Personally, I'd NEVER use an aftermarket electric fan: The OEs have a lot riding on those electric fans, and they've spent the money to make a nearly bulletproof component. Aftermarket companies don't have the resources or the budget. They didn't send their components through torture testing in Death Valley to find the weak links--the OEs do.

  12. plymouth52
    Joined: Sep 16, 2006
    Posts: 53


    Make sure that the Thermostat is not stuck, if it is sticking electric fan would multiply this issue. It will only cool the fluid in the radiator, and not the Fluid in the engine
  13. choptvan
    Joined: Mar 19, 2010
    Posts: 2,161


    So. other alternatives. Intake leak? Carb base gasket leak? Vaccum line leak? Running lean will cause it to overheat as well. NO fan in the world can help that out when it starts. Easy way to find out. Either spray carb cleaner around slowly and wait for the idle to change wehn you fins a leak. Or, if she has pretty paint, use water. It will essentially drown it. You will notice.

    Timing? If it is wrong, that will cause it as well. Just like how it was explained to make sure you have the CORRECT vaccum ot the distributor. That will effect the timing.

    As for th electric fan needing a shroud. For sure. Mechanical, electric whichever. THe air needs direction. Otherwise as stated, it is just pulling from all over. Not where you want it to pull from.
  14. flyin-t
    Joined: Dec 29, 2004
    Posts: 1,372


    That's what i was going to ask. I got a bad thermostat years ago and always check a new one now in a pot of water on the stove and a cooking thermometer just to make sure they're working right.
  15. bobby_Socks
    Joined: Apr 12, 2006
    Posts: 938

    from ǑǃƕǑ

    This happens more times than others want to admit. If it is it will be an easy fix.
  16. 68vette
    Joined: Jul 28, 2009
    Posts: 306


    I just had a sheet metal shop make me a shroud for my 49 chevy with 283. I measured the steel mech fan and it stuck out 3 inches from the rad. I ordered a flat piece of 16ga sheet metal 2 and 3/8 inches wide and 40 in long...cost me 11.00. I will buy a piece of rubber hose and slit it all the way and put it up against the rad. NO AIR LEAK that will cool the car without any problems at any is 2/3 in the shrould but does not have to be completey round and it needs to be about an inch or so from the tips of the fan.

    Do that and you will have no problem if the rest of your cooling system is good.
  17. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,026


    I don't see if the OP said he had his vac advance hooked up? This may be important..
  18. mike in tucson
    Joined: Aug 11, 2005
    Posts: 502

    mike in tucson
    from Tucson

    as 68vette said, the shroud is important. Here are some tips/bullets:
    1. You gotta have a shroud if you have a fan. A shroud directs the air from thru your radiator to your fan. The fan doesnt care where the air comes from so you have to force the issue.
    Fans move air by pulling from the LEAST resistance area...thru your radiator may not be the least resistance IF pulling from the sides is lesser resistance.
    2. A shrould should not have gaps between the shroud and the radiator. It should fit closely (1/4"max gap or less). Foam weatherstripping is a good seal.
    3. An electric or mechanical fan can be TOO close to the radiator. The center of a fan doesnt pull air. Think of the fan as a donut. Put it close to the radiator and the effective radiator area is a donut.
    4. The 2/3 of the blade tip inside the shroud is good, leave clearance for your engine to move relative to the shroud (motor mount twist)
    5. When going at highway speed, the fan is an inpediment to the air flow
    6. Air has to escape from under the hood...cooling fans are not good at pressurizing the underhood area
    7. A fan shroud should cover the entire radiator finned surface if possible. If it doesnt, you are reducing the radiator area.
    8. The shroud shouldnt be any closer than 3 inches to the radiator surface, air has to come thru the radiator cleanly....if the shroud is too close, the air cant flow freely.
    Resistance (or lack of resistance) is all-important to the air flow.
  19. Let me preface by saying I don't like electric fans!

    I believe a good engine driven fan is your best bet,,but your wimpy 4 blade fan ain't gonna do the job,,I have the 6 bladed steel,,non flexible wide blade fans on all 3 of my hot rods ,,,I think if you will try one on your car and use the shroud(Incidentally,I don't use one) your problems with over heating may possibly be cured. HRP

  20. creepjohnny
    Joined: Dec 1, 2007
    Posts: 878

    from Sunland,CA

    I disagree with the 160 thermostat.
    Most engines are designed to run around 180-190 hot. Naturally that motor will heat up to 160 by just sitting in your driveway. And it may run cool around the block but once it's at 160 or hotter that thermostat will stay open and keep flowing, this not allowing cooling time for the water in your radiator. It especially won't work if its 85 or hotter outside. Keep your 180 or 190, or whatever factory spec is for your thermostat.
    My 65 bonneville 389 w/ 4bbl. Guy I bought it from changed the 180 to a 160. He never drove it anywhere except work and bobs big boy, less than a couple miles from his house. I bought it, drove it away at 165 degrees, quickly got to 205-210. Had to pull over twice to let it cool down. It was 85-88 degrees outside. And moderate traffic.
    Switched the thermostat to 180 and no more troubles.
    All these guys make good points. Start simple, then spend $$.
    If it were me;
    Radiator size- 3 or 4 row. Mix coolant properly, add water wetter, burp system, 13-15 lb rad cap. Check timing, make sure not too advanced. Switch to 7 blade fan, I usually mount within 1-2 inches from radiator. Fan clutch is ugly but useful! Make sure air
    Coming into engine bay can escape. Header wrap. Electric fans, can be useful in traffic, always make electric fans switch operated, better you control it when you want to.
    avoid traffic and hot days.
  21. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,260


    Spal fans are OEM on Ferrari's. They are used as after market fans on Hot Rods because they work.
  22. BrandonB
    Joined: Feb 24, 2006
    Posts: 3,228

    from nor cal

    LISTEN to what he said!!^^^^^^^^^^^^^^^
  23. CadillacKid
    Joined: Oct 15, 2002
    Posts: 1,507


    The distributor vacuum advance was and still is on the driver side front port of the carb...this should be full manifold vacuum...I switched it to a 160 stat yesterday, and it stays around 180 to 190 in only heats up now when you sit at stop lights for a long time, and lights here in Austin are thing that I forgot about was we just lowered the idle on the engine before all of this started happening...the water pump pulley is huge...running 1 to 1 off of the I just picked up a smaller one and we'll see if that helps too! :) There's plenty of airflow coming through the pulls in a rag from about 5 inches away...and the electric fan is a 16 inch curve blade mounted in the middle of the 24 inch wide radiator...
  24. Pats55
    Joined: Apr 29, 2013
    Posts: 517

    from NJ

    I went through all of this with a avanti a direct drive fan in the end worked the best.I was a three pack a day I had a slight heart attack got a couple stints and after the third day I had it beat. I smoked for 47 years, every picture of me had a cigarette my hand. You don't need electric cigarette just don't fire up anymore and in three days you won't need them. Good luck. Sorry for the sermon
  25. CadillacKid
    Joined: Oct 15, 2002
    Posts: 1,507


    Thanks Pat...I know everybody means well about the smoking...I actually welcome the "sermons" these days...they help strengthen my conviction to quit :)
  26. CadillacKid
    Joined: Oct 15, 2002
    Posts: 1,507


    And I must say, after all of the time away, it sure feels good to be back on the HAMB :)
  27. mustang6147
    Joined: Feb 26, 2010
    Posts: 1,847

    from Kent, Ohio

    SO is Castrol, but people still use Valvoline?

    I want to mention 1 other thing.... When putting the shroud on, its pretty important, that the air moving blows out at a 45 degree angle..... It doesn't have to be perfect, but not blowing straight back is ideal. Some always will though.

    The theory behind this, is, people put fans on their engines, and it blows straight back against the firewall, causing pressure in the engine compartment, and over heating. But when you take the hood off, problem goes away...

    The 45 degree angle is also directly related to the fan placement in the shroud, to far in, no air circulation, to far out, blows straight back..... I deal is approx. half to 2/3rds in.....

    As stated before, I went through all this, and read for months on theory and engineering. While getting input...
    Last edited: May 25, 2013
  28. As soon as me and my buddy can line our schedules up, I'm swapping to a Dodge cross-ref radiator I bought and a mechanical fan setup. My current small mystery radiator plus slim profile Spal fan don't quite get it done but it's more the radiator's fault.

    Good luck OP.

    I don't like having engines running over 190, I get nervous in sitting traffic... 190 becomes 200... 205.. 210... start hearing some puking from the overflow...
  29. wheels1950
    Joined: Jun 13, 2001
    Posts: 550

    from PA. USA

    Maybe its not the fans at all! .
    Didn't see anything about a new or used water pump
    Saw the fins eatin away and slow the flow down at speed.
    Just sayin might not be the fan!!
  30. eppster
    Joined: Jan 26, 2011
    Posts: 223


    In the last six months I've had two friends come to me with supposed heating problems , one was a bad dash ground and the other was a bad guage. Get a laser temp. gun and point it right at your thermostat housing, that reading is your true engine temperature. 205 degrees sitting at a stoplight in 95 degree weather to me is not hot, hot is spitting water. Is it optimum, probably not but new engines run those type of temps all the time in similiar conditions.

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