installing thermo switch on '79 308GTS | FerrariChat

installing thermo switch on '79 308GTS

Discussion in 'Technical Q&A' started by groovzilla, Feb 21, 2004.

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  1. groovzilla

    groovzilla Karting

    Nov 28, 2003
    seattle, wa.
    Full Name:

    again as always i appreciate everyone's help in my locating and troubleshooting the thermo switch which operates the radiator fans...

    it turns out that when shorted out, the radiator fans DO work correctly so it is the thermo switch...

    as recomended, the low temp, 2 pole(180 degree)22mm vw rabbit switch available at a local parts store for $12.99...not bad...i am planning on installing it tomorrow..

    **my question is when installing the switch is there any way to prevent the entire contents of coolant from escaping...
    **also how is the system bled to insure no airblocks..

    regards to all the crew...

    william ceriale seattle, wa.
  2. ChrisfromRI

    ChrisfromRI Karting

    Jan 28, 2003
    Foster, RI
    Full Name:
    Chris F
    It's not too bad if you're quick!

    I take the new thermo-switch and put a new gasket on it in advance. Then I lay the new thermo-switch right next to the old one and get everything else like loose wires well out of the way so I have a clear area to work.

    Make sure that the expansion tank is capped and everything is tight to keep a vacuum in the cooling system. Then loosen the old thermo-switch with your wrench, and put the wrench down. Now, as quickly as possible unscrew the old one and screw in the new one. You should be able to do this in under three glugs (glug, glug, glug) of coolant.

    OK, tighten the new thermo switch as appropriate and reinstall the wires.

    Before doing anything else loosen the bleeder screw at the top of the radiator and bleed out as much air as possible. Once coolant starts coming out re-tighten the bleeder screw. Go around to the expansion tank and remove the pressure cap and top up the coolant to the seam that is about two inches down from the top of the neck. Re-install the pressure cap.

    Start the engine and turn both heaters on. With the engine running, both heaters on, and the system sealed it is time to open the bleeder screw at the top of the radiator and bleed out any air until coolant comes out. Once you are sure you have the system bled shut it down and let it cool down. Later, after it is cool, open the pressure cap and check the coolant level. Add to the seam. You should be done!

    Kind Regards, Chris

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