Coolant overflow tank? | FerrariChat

Coolant overflow tank?

Discussion in '308/328' started by Perfusion, May 15, 2006.

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  1. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
    Full Name:
    Aaron
    I met a fellow FChatter today with a '75 308GT4, and I noticed that his car had a coolant overflow tank mounted in the engine bay where my gas vapor canister is located. My car has been steadily losing coolant over time, yet I have no idea where it's going! I've put about 2 full bottles of coolant (mixed 50/50 with distilled water, of course), so that's ~4 gallons since February. The kicker is, I *never* have a drop on the garage floor. It's definitely going somewhere, though, and I think it may just be going out the "blow-off" (or whatever it's called) tube near the neck of the coolant reservoir and down onto the road as I drive.

    Just wondering if anybody else has rigged up a similar setup - it seems like it could really help. Thanks in advance -

    Aaron
     
  2. DavidDriver

    DavidDriver F1 Rookie

    May 9, 2006
    4,424
    Grass Valley, CA
    Full Name:
    David Driver
    Mine is located in the right rear, whilst [I love sounding British] standing behind the vehicle. My canister has been removed.

    I would suspect that your assumption is true, as you are losing it so slowly. But then again, perhaps because you are mixing water with the antifreeze, the water (alone) is simply evaporating? If you're mixing water with your antifreeze, it "will" evaporate at some point. Especially if you run a little hot. The hotter, the quicker.

    PS: Cannibalized a hose from Pep Boys with a pair of tin-snips and added 2 new clamps. Total cost: $28.10. Plus 2hrs labor (incl. the trip to Pep Boys).

    Back on the road again... Yippiee!!!
     
  3. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
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    THE Birdman
    If you are overfilling the expansion tank, you will lose coolant because the tank should only be about half full when the car is cold. As the coolant expands at higher operating temps, the overflow tank collects the coolant. If it's full when cold, the coolant will overflow as the car heats up.

    The other possibility is a bad head gasket and the car is actually eating the coolant. If that's the case, it's bad. You can check this by looking at the coolant in the expansion tank and see if there is any oil in it.

    Birdman
     
  4. 330gt

    330gt Formula 3

    Nov 12, 2004
    2,097
    Seattle, WA
    Full Name:
    Kerry Chesbro
    The other possibility is a leaking water pump. These usually only leak when the engine is running. Drips out of the weep hole in the bottom don't make it to the floor as they evaporate on the hot surfaces they hit. A careful look at the bottom of the pump may show antifreeze traces. Or run the engine in place a while (don't get it too hot) and then feel on the bottom for any antifreeze.

    Regards, Kerry
     
  5. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
    Full Name:
    Aaron
    I didn't want to hear that....but perhaps I need to. I will say that, looking down into my coolant reservoir with a flashlight, it doesn't look like pristine mountain spring water. Then again, it doesn't look like an oil & vinegear salad dressing, either, so I don't know what to think... Maybe I'll take a picture if I can get the digi cam to focus on the surface of the coolant.
     
  6. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
    Full Name:
    Aaron
    A leaking WP was definitely something I'd considered. The WP on my Corvette leaked once, but fortunately for me, the orientation of the serpentine belt was such that it flung the coolant up onto the underside of the hood, leaving a very tell-tale "stripe." Sounds like this isn't the case on the Ferrari. I'll try running the car in place and see what happens.

    ********

    Now...my impression of the "proper" coolant depth in the expansion tank (lemme make sure I'm talking about the same thing as you guys - a black tank at the right-rear corner of the engine bay with a metal cap) is this -- according to the owner's manual, the coolant should be 6cm from the top of the neck when cold. That distance corresponds fairly well with the "Max" line that is stamped into the tank, visible on the outside. Six cm. from the top doesn't leave much room for expansion. But even if I *were* losing coolant from the little blowoff hose as the volume expands, I would assume that it would only continue to happen until enough coolant was lost so that, during future runs, no coolant would overflow. However, my car seems willing to run itself dry (if I let it get that far, which I don't). That seems pretty conclusive that it's disappearing from somewhere else. I just have to find out where...

    Crap.
     
  7. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,104
    Cowboy Capitol of the World
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    Brian Crall
    Don't get too caught up in the books description for coolant level. As said the tank should be about 1/2 full when cold. If it continues to lose coolant to the point it regularly looks as though there is nothing in it and it has a Ferrari cap, throw the cap over the nearest hedge and buy a Stant Lever vent cap at about a 13 lb rating. Do that no matter what. The Italian caps are trash and only work for about a year. Their only real use is for show.
     
  8. Rival

    Rival Formula Junior

    May 12, 2005
    399
    Misipi
    WTF??????
     
  9. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
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    Aaron
    I'll definitely do that... I never even considered the cap. Care to elaborate a little more on the mechanics of how the cap plays into things specific to my "symptoms"?
     
  10. Rival

    Rival Formula Junior

    May 12, 2005
    399
    Misipi
    Your cap could be old enough to allow coolant to bypass it. The springs and/or seals can get old, and when pressure builds up, rather than staying in the tank, it can leak out. That's why when doing a leak-down test to find coolant leaks, a shop will pressurize both the tank and the cap.......it has to be leaking from either the cap or the tank - or further downline from the tank in a hose, headgasket, etc.

    By the way, though a bad headgasket leak could possibly displace oil into your expansion tank, it's unlikely it would be visible. Accordingly, there are tests that can be run on coolant from the tank that can detect the presence of combustion byproducts. Any presence of these will indicate a head gasket issue....
     
  11. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
    79,380
    Houston, Texas
    Full Name:
    Bubba
    Ditto.....they replaced my cap with an uprated one as well.......

    When they get weak it lets it blow by out the overflow, I suspect...I know I exercised that last time my water pump seized and melted the belt off!
     
  12. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
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    Aaron
    Hmmm....good info, all. Thanks very much. You think that cap is available locally, or is that an internet special only?
     
  13. don_xvi

    don_xvi F1 Rookie

    Nov 1, 2003
    2,934
    Outside Detroit
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    Don the 16th
    You can get one locally, check the 308 cross-reference thread for the number. I don't like the way mine fit, it's hard to get on & off. :|
     
  14. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
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    THE Birdman
    Interesting. We had an old Honda that had a bad head gasket and the oil in the coolant (and coolant smell in the exhaust) was impossible to miss. Black goo on top of the coolant in the reservoir.

    Birdman
     
  15. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
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    THE Birdman
    Aaron,
    I will bet that your problem is much simpler. Replace the cap and if that doesn't fix it, check the waterpump and any hose fittings that can drip on anything hot.

    Coolant leaks can be a pain to find for sure, but you will find it.

    Birdman
     
  16. Ken

    Ken F1 World Champ

    Oct 19, 2001
    16,078
    Arlington Heights IL
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    Kenneth
    LOL, that was my reaction too. I have an open cooling system (no overflow tank; just a hose that pees on the rear tire) and I don't lose anything (unless the car overheats, which it doesn't do).

    Ken
     
  17. Perfusion

    Perfusion F1 Rookie

    Oct 16, 2004
    4,151
    Marietta, GA
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    Aaron
    Hmm...okay, so then an open system *can* work properly.

    Step 1) New cap. Seems like a good idea, anyway.
     

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