348 oil cooler - 2 problems!! | FerrariChat

348 oil cooler - 2 problems!!

Discussion in '348/355' started by angelis, Aug 10, 2006.

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  1. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
    Full Name:
    Sy
    The oil cooler fan is'nt working, so the oil temp is always high and I can't figure out the problem.

    So far I've done the following;

    - Changed the oil fan relay - ok
    - Checked the fan conection - ok
    - Checked the fan itself - ok

    The problem seems to be with the wire from the oil cooler thermostat, which does'nt seem to be getting any power.

    The local mechanic said it was either a relay problem or a wiring fault.

    I've looked at the manual and can't seem to identify which relay/fuse it could be. Anyone know? Any other fix?

    The other major problem is that we can't remove the oil thermostat as it's frozen solid.

    Thanks
     
  2. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,966
    Milton, Wash.
    Full Name:
    Jeff B.
    #2 Miltonian, Aug 10, 2006
    Last edited by a moderator: Sep 7, 2017
    Here's what you do to test the oil cooler fan - very simple.

    Pull out fuse 15. It's the third one from the right in the lower row (20 amps). Make sure it isn't blown, and put it back in.

    Pull out relay "O". It's the center one in the bottom row in the footwell panel.

    There are five slots in the relay panel for the five terminals on relay "O". Take a jumper wire with two male spade terminals and jump the two positions shown in the picture (top center to bottom center, terminal 30 to terminal 87). It doesn't matter whether the ignition key is on or off.

    As soon as these terminals are connected, the oil cooler fan should come on. If it doesn't, then there is a problem either with the wiring, the fan, or the ground. If it DOES come on by jumping the terminals, but never comes on any other time, then we can look at some other possibilities.

    The thermoswitch for the oil cooler fan should close at 90 degrees C, turning on the fan, and open again at 80 degrees C, turning off the fan.

    There is normally no power running to the thermoswitch or to the fan motor, so don't check for power in the back. I can draw you a good diagram if you wish.
    Image Unavailable, Please Login
     
  3. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
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    Sy
    Thanks Jeff. I'll check it tomorrow.
     
  4. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
    Full Name:
    Sy
    I've replaced the 20A fuse.

    I've checked relay "O" with the jump wire and the fan does'nt switch on.

    I also checked the LH & RH fans with the jump wire and they both come on.

    I know the actual fan works as the mechanic gave it outside power and it worked fine.

    Looks like a wiring problem somewhere?

    I think its the wire that's attached to the oil thermoswitch as the mechnaic who checked said it had low power.

    How can I fix it? Or do I need to go to a specialist?



    By the way, everyone should have one of those jumper wire. I've never used one before and they are invaluable for testing relays. Fantastic tip :D
     
  5. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,966
    Milton, Wash.
    Full Name:
    Jeff B.
    OK, next thing to check. Do you have a 12 volt test light? You need to see if you are getting power to the bottom slot for relay "O" in the box. This should be battery power, not switched power. My test light isn't pointy enough to reach into the slot far enough to touch the contacts, so you may need to plug in your jumper wire, then check for voltage with the tester.

    When you jump the contacts as shown in the picture, you are bypassing the relay and the thermoswitch and sending 12 volt power directly to fuse 15. From there, it goes directly to the oil cooler fan, then to ground, so the fan should come on (it does on my car). I'm not sure where the ground is located, but I'll look and find out.

    For now, just check for power at the relay slot and report back.
     
  6. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
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    Sy
    Jeff, thanks for all your help.

    Got it fixed by someone. trned out it was dirty connection and the oil thermo sensor. The specialist (QV engineering) managed to remove the old one which was rusted solid and threaded a new one in. Not something I could have done to be honest.

    Thanks again. :D
     
  7. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
    Full Name:
    Sy
    And my oil fan has stopped working again!!!!
     
  8. angelis

    angelis F1 Veteran
    Owner

    Jun 18, 2004
    6,400
    London, England
    Full Name:
    Sy
    Checked everything and it looks like it's the thermo switch again.

    This time I'm going to buy the OEM. More expensive, but the last one lasted 12 plus years. The cheaper intermotor only 1.5 years.

    I'm also going to buy a new rad switch as well. only £9.
     

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