what are the hoses from the expansion tank to engine ? | FerrariChat
Buy

what are the hoses from the expansion tank to engine ?

Discussion in '308/328' started by [email protected], Aug 17, 2009.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. andy2175m4@yahoo.com

    [email protected] Formula Junior

    Dec 7, 2008
    473
    Los Angeles, CA
    Full Name:
    Andy Rein
    #1 [email protected], Aug 17, 2009
    On the 1982 308 GTSi, regarding the expansion tank, I see there are two hoses, a 1" heater hose that goes from the lower part of the ex. tank, to the radiator return pipe, right next to the airpump diverter valve, and that's clear, but there is also a 3/8" hose that goes from the upper section of the expansion tank to the coolant piping on top of the engine. What is the function of this smaller hose on the block return side of the cooling plumbing ?

    thanks

    Andy
     
  2. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,800
    Full Name:
    F683
    #2 eulk328, Aug 17, 2009
    Last edited: Aug 17, 2009
    It's not just an expansion tank but rather an expansion/recirculation tank. Coolant constantly comes into the tank via the small upper hose and leaves through the lower large hose.

    Because of this, the temperature of the coolant in the tank is, for all practical purposes, the same temperature as the coolant in the engine block. The Aux. air valve (cold idle valve) is mounted under this tank and starts to close down (let in less extra air) as the coolant tank it's attached to gets hotter (thus reducing your idle speed). Some of these aux. valves also get additional heating from a built-in heating element and certain models (and certain markets) have an additional thermal switch (for smog stuff or something) screwed into the coolant tank. This switch is activated by the heat of the coolant/coolant tank.

    So... as you can see it does more than just allow for expansion and you don't want it to be run very low (not to mention the possibility of introducing air into the system if it's low).

    If you don't have good or any coolant flow coming out of the small hose into the coolant tank you need to address the issue as this can cause an inaccurate coolant temp. representation in the tank. The metal nipple that feeds this hose (on the other end of the hose) can get severely blocked with gunk. It should be checked and cleaned whenever you have access to this area.


     

Share This Page