Subaru Overheating Problem

Discussion in 'General Motoring' started by Howard M. Stark, Oct 11, 2003.

  1. Hi,

    Sorry to repost but thought that I should mention in the title that the
    car is a Subaru.

    I have a 1999 Subaru Outback with ~81000 miles. On a recent trip the
    engine temperature started to fluctuate between overheat (top of the
    gage) and normal every few minutes. I found the oil level down 2 quarts
    which I added and the coolant overflow tank almost empty; I added water.
    I then drove car about 20 miles before getting it towed to a Subaru
    dealer. They found oil in the coolant and feel that either the head
    gasket is gone or in addition the block needs replacement.

    They might be right, but I have some questions:

    1. If there is leakage between the cooling system and the oil why is
    there no water in the oil. I don't know the relative pressures.
    2. Why the oscillation in temp. This it seems to me might be caused by a
    bad thermostat.

    I need a second opinion.

    Thanks for help in advance.
     
    Howard M. Stark, Oct 11, 2003
    #1
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  2. Howard M. Stark

    Tony Hwang Guest

    Hi,
    Sounds like blown head gasket to me. Hope that's all, no warped
    head or cracked block.
    Good luck,
    Tony
     
    Tony Hwang, Oct 11, 2003
    #2
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  3. Howard M. Stark

    TG Guest

    Combustion pressure make things go wherever it wants to.
    Again, combustion gas is VERY hot and can quickly raise the temp. A blown
    head gasket can be somewhat intermittent but must be fixed or much more
    serious damage will result. TG
     
    TG, Oct 11, 2003
    #3
  4. Howard M. Stark

    Tony Hwang Guest

    Hi,
    Isn't there a chemical you can put in the radiator and detect exhaust
    gas?
    Tony
     
    Tony Hwang, Oct 12, 2003
    #4
  5. Howard M. Stark

    TG Guest

    There are actually some little test strips of paper but I can't seem to find
    them on the net right now.
    I think a "sniffer" for the tailpipe used in emission testing will work if
    held near but not submerged in the filler neck.
    You can also use a cooling system pressure tester at the filler neck and
    instead of pressurizing the system to look for leaks just start the engine
    and see if the gauge rises...it shouldn't. TG


     
    TG, Oct 12, 2003
    #5
  6. Howard M. Stark

    TG Guest

    You can also pinch off the overflow hose and then rubber band a plastic bag
    over the filler neck and see if it expands when the engine is running....I
    have found balloons that would fit. TG
     
    TG, Oct 12, 2003
    #6
  7. Howard M. Stark

    Bill Putney Guest


    I think someone reported on this ng a year or two ago that they
    successfully used carbon monoxide detectors (can't rememer if it was
    strips or the electronic gadgets) like you'd buy in Walmart, Lowes, etc.
    for home use to detect exhaust gas. Do a goolge search on this ng if
    interested on tbhe details.

    Bill Putney
    (to reply by e-mail, replace the last letter of the alphabet in my
    address with "x")
     
    Bill Putney, Oct 12, 2003
    #7
  8. Howard M. Stark

    Peter Berkey Guest

    I had similar trouble with my '97 OBW back in June. I made the mistake of
    going to a Subaru dealership that everyone recommended to me. The
    dealership (Carr Subaru in Beaverton, OR) was supposed to have had the
    "best" service dept. in the business in one the biggest Subaru regions US
    (the Pacific NW). Well, they charged me top dollar ($1600) and did very
    poor work.... they forgot to tighten various essential clamps when they
    reassembled the engine. So, I had to go through 2 major breakdowns stranded
    far away from home AFTER having to spend all that time & money for repairs.
    THEN spending much time and effort to get the car BACK to the dealership so
    they could fix what should have been fixed properly the first time. They
    never even said "sorry about that".

    My advice? Take the time to make sure you know and understand fully what the
    problem is with your vehicle.... then choose the shop very, very carefully.
    Try to meet the person who is actually going to do the work and make sure
    you feel comfortable with that person tearing apart your engine and then
    reassembling it. If he shows any signs of drug & alcohol use, refuse to
    have him do the work. You cannot be too careful about this, especially when
    it comes to this sorta stuff. Sounds like you may have some reservations
    about this particular Subaru dealership. You may want to get the car
    diagnosed at an independent shop, especially if it's a possible blown head
    gasket. Hope this helps.


    -- Pete
     
    Peter Berkey, Oct 12, 2003
    #8
  9.  
    Howard M. Stark, Oct 12, 2003
    #9
  10. Howard M. Stark

    Seth_thedude Guest

    They might be right, but I have some questions:

    1. If there is leakage between the cooling system and the oil why is
    there no water in the oil. I don't know the relative pressures.

    Oil pressure is higher than coolant pressure therfore oil only in coolant.
    Oil could have leaked past the head gasket.

    2. Why the oscillation in temp. This it seems to me might be caused by a
    bad thermostat.

    When a temp sensor gets an air bubble around it, it can behave erratically.
    If you have air bubbles in your cooling system it sounds like a head gasket or cracked head.
     
    Seth_thedude, Oct 13, 2003
    #10
  11. Howard M. Stark

    Pete D Guest

    They might be right, but I have some questions:

    1. If there is leakage between the cooling system and the oil why is
    there no water in the oil. I don't know the relative pressures.

    Oil pressure is higher than coolant pressure therfore oil only in coolant.
    Oil could have leaked past the head gasket.

    2. Why the oscillation in temp. This it seems to me might be caused by a
    bad thermostat.

    When a temp sensor gets an air bubble around it, it can behave erratically.
    If you have air bubbles in your cooling system it sounds like a head gasket
    or cracked head.

    All exactly correct, I had a small leak in one of the head gaskets and it
    did exactly that. Unlikely to be a thermostat.
     
    Pete D, Oct 13, 2003
    #11
  12. Water may very well be getting into the oil. But those temps are high
    enough to keep it boiled off. Not so with oil in the cooling system.

    In the old days, you'd get 'chocolate mousse' collecting under the
    filler cap. I would be surprised if his PCV valve and hoses weren't
    clogged with emulsified oil and coolant.

    Also, as has been mentioend before in oyher threads. When the coolant
    system is near its at its boiling point in some areas of the engine,
    but still below that point elsewhere, odd things begin to happen. Like
    geysers. The heat up, deep down its hotter than at the surface, a small
    bubble forms, moves up where less pressure lets it expand some, maybe it
    cools off enough to collapse, maybe not, it cause some 'burping out' of
    water in the water column, now there is less pressure in the system,
    larger bubbles explode forcing a lot of water out, repeat but with
    different dynamics in the car 'cause there is no replenishment of water
    as in a geyser.

    Throw in old gummed up radiator caps, questionable radiators, sticking
    thermosatats, broken fans, highway followed by stop&go driving, etc.


    Carl
    1 Lucky Texan
     
    Carl 1 Lucky Texan, Oct 13, 2003
    #12
  13. Thank you all for your insights and help.
    Howie
     
    Howard M. Stark, Oct 13, 2003
    #13
  14. Howie, It is possible to have water in oil or vice versa but NOT
    necessarily both together - it just depends upon what is cracked and where.

    With any luck you just have a head gasket problem and it will go away after
    replacement. You should expect to get the heads pressure tested with the
    valves out to be sure of no cracks.

    Ref. the gauge fluctuation, not many people realise that the sender for the
    temp gauge neds to be immersed in coolant to operate correctly and if the
    fluid leaks or boils away the gauge either will not register at all or will
    vary wildly.

    We build Subaru engines all day every day and apart from 2.5 Dohc's in the
    UK I have NEVER seen a cracked or porous cylinder block on a Subaru.

    Good luck David API Engines Ltd England www.apiengines.com
     
    API Subaru Impreza, Oct 14, 2003
    #14
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