radiator fans...not working???

Discussion in 'Technical Q&A' started by groovzilla, Feb 12, 2004.

  1. groovzilla

    groovzilla Karting

    Nov 28, 2003
    seattle, wa.
    Full Name:
    thanks to all who responded to my oil/coolant temp question...

    i am sure my water temperature guage is working acurately...i noticed today after taking a much longer drive(16 miles)that when i returned home to the city the temp guage was over 200 degrees...closer to the 250 mark..

    i was parked in my driveway and turned the car off and did not here(or have ever heard)the radiator fans come on...

    **is there a certain tempurature when the fans turn on??

    is there an idiot light for the fans??..

    my car was thoroughly checked out by ferrari specialist before i purchased in dec. but i know things fail...

    william ceriale sea, wa.
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  3. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    The thermo switch usually turns the fans on around 195 degrees, plus or minus a few. If you are not hearing them come on, you might just go ahead and replace it. It is a common one used on VW rabbits (two pole). When you buy it, ask for the cooler temp one (turns on around 180). Shouldn't cost more than $20 or so.
  4. groovzilla

    groovzilla Karting

    Nov 28, 2003
    seattle, wa.
    Full Name:
    dave thanks for the help again...i am sure you will be sick of me soon with all these questions but i am still shaking the car down and it is a little different than the '59 porsche's...

    could you tell me where the radiator fan switch is located??...i will replace it this week and see what comes of it...

  5. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    Right side of radiator, brass thingy with wires connected.
  6. ferrarifixer

    ferrarifixer F1 Veteran

    Jul 22, 2003
    Full Name:
    Phil Hughes
    The switch is right down the bottom of the radiator, but you can get your hands to it ususally. Before you replace it "willy nilly", just unplug and short it's two wires together. The fans should then come on (with ignition on) immediately.

    The right hand fan should work with the AC turned on.

    The thermo switch will have it's operating range stamped on it.

    When the fans do come on, observe that both are working, and also that they are turning the correct way.

    They should blow or pull air through the radiator from front to back, and NOT blow the air out the front of the car. Use a sheet of paper, or smoke, to check if not sure. I found yet another car last week with backwards fans........I can't believe how many there are.

    If they turn the wrong way, they have been wired backwards. Simply reverse the wires on the fans once the grille is off. (I'm assuming 308 here, 328 different, but similar principle).

    Do you know how to bleed the radiator.........search the archives or read your owners handbook, it's important, especially after maintenance.
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  8. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    Check your radiator. Is it hot when your gauge is reading 200? If not you have now thermostat in your system. This will cause coolant to bypass the rad. and therefore your fans won't come on. Test the switch easily by removing the two spade connectors and touch them together with the key on. Do the fans come on?
  9. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    You can have a car checked by a specialist and something go wrong the next day. You know inspections sometimes miss items.
  10. ChrisfromRI

    ChrisfromRI Karting

    Jan 28, 2003
    Foster, RI
    Full Name:
    Chris F
    Mine turn on at 195 F due to the thermo-switch that you see when you look down at the bottom of the radiator from the front passenger corner of the car with the front hood up. These thermo-switches unfortunately do fail fairly regularly.

    With the car running up to temperature and your fans not turning on then pull the two push-on spade connectors off of the thermo-switch and short them together and see if the fans turn on. They should turn on if the fuse, relay and fans are OK. The thermo-switch contact closes at temperature and is open below temperature. Watch out for your fingers and the two fans as they turn on.

    My thermo-switch has failed several times, so I have now wired a toggle switch under the dash in parallel with the two thermoswitch leads so I can bypass the thermo-switch and turn the fans on manually with the toggle switch in the event that my thermo-switch fails again.

    If/when you do replace your thermo-switch you should also buy an extra gasket with the new thermo-switch. Then you can pre-install the gasket on the thermo-switch to speed up the time it takes to unscrew the old one and screw in the new one, so that you only lose the minimum amount of coolant onto the under-pan and floor.

    BTW, my thermo-switch failed on the road twice and I just taped the two terminals together with electrical tape so that the fans would run continuously as I drove home. However, I do not believe the fans are rated for continuous duty so this would not be a good long-term solution.

    Kind Regards, Chris ***as
  11. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    Your fans are most likely Lucas. It's weird, but I had both of mine fail at the same time. So, if shorting the thermo switch doesn't do anything, check for voltage to the fan motors. If no voltage, it could be a relay or fuse/fusebox problem. If you have voltage, give the fan blades a little nudge. Often a shot motor will spin a bit if helped. This will tell you if you need a motor R&R.

    The Lucas fans usually fail because the brushes wear out. You can replace them yourself for $10 or so. Requires a soldering iron. Search the archives for "Pantera fan brushes" for a source. Lacking that, I can look it up when I get home, if it turns out that you need them.

    A more permanent solution (and, again, I'm going here on the supposition that the fan motors pooped out) is to buy the "QV" motors. They are much better in quality, and bolt right in. Requires some simple alteration to the wire connectors, tho.

    As ChrisfromRI suggested, a toggle switch to 'aid' the thermo switch isn't a bad idea. I have one and just leave the fans on all the time when driving in the city during the summer. Shouldn't be needed on the open road, tho.

    The fuseboxes on these cars are notorious for doing a meltdown. Check that the fuses are all tight and that everything looks OK. When you have time, you should pull the fusebox and solder all of the riveted connections as a preventative measure. Write back and/or do an archive search when you get ready to do this.
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  13. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    I would 1st check the fuse block and the fan relays. I had the same problem and when I shorted out the rad. temp switch nothing happened. Went to the fuse block and found that the relays didn't turn on. Went to the fuse and found a cracked fuse BLOCK which did not give me enough voltage to pick the relays. I did the NAPA fuse block conversion and fans work great.
  14. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    I too had intermittent fans that turned out to be caused by a bad(partially melted) fuse box.
  15. stevej33

    stevej33 Karting

    Feb 16, 2004
    Lincoln, UK
    Full Name:
    Steve Jollands
    ive just experienced the same fualt on my 84' mondial qv,
    but it would appear that the rad is not warming up and therefore i think
    i have a thermstat problem, as the fans work when shorted out...
    the car has been undergoing a 6 month renovation, and has not been used for some time, but was ok when last used!
    steve j (uk)

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