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Cooling system full of oil

Discussion in '1994-2004 V6 Mustang Tech' started by Jason131, Aug 24, 2019.

  1. Jason131

    Jason131 New Member

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    I have a 99 3.8L and recently discovered the cooling system is full of oil. It doesn’t appear to have any coolant in it at all. Is it possible that it just has a blown head gasket or is it a cracked block? I’m not the best mechanic but I can do what I have to do when I have to do it. I’m trying to decide if I should try to tackle this myself at home or take the car to a mechanic. About 5 years ago I had a mechanic take the heads off and fix some leaking valves causing the car to smoke. He charged me $700 and this is the first trouble we have had with the car since. I need any advice or help that can be provided.
     
  2. Pete fender

    Pete fender Pete Fender

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    The head gasket would be the number one suspect, but the 3.8 has a tenancy to have lower intake manifold gasket problems.
    Water coming from the coolant crossover in the lower manifold can leak into the valley area between the heads.
    Do a compression test, and inspect your plugs for oil, to rule out the head gaskets.
     
  3. Jason131

    Jason131 New Member

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    Thank you for your reply. I did forget to mention that the car overheated a few months back. I got it pulled over as quickly as I could but I was stuck in traffic with no way to pull over for almost 10 minutes.
     
  4. Jason131

    Jason131 New Member

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    Also when I say it’s full of oil even the coolant reservoir is full half way to the top with oil. I’m sorry I keep thinking of details that I missed in my initial post.
     
  5. Pete fender

    Pete fender Pete Fender

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    The manifold gasket most likely was damaged when you overheated.
    Eventually, the silicon ring or seal around the coolant crossover got pushed in.
    I may still have one I replaced, if I do I'll take pictures of it, you'll see what to look for.
     
  6. Pete fender

    Pete fender Pete Fender

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    100_0707.JPG

    You can see the silicone seal hanging down.
    The gasket is plastic, and a piece had broken off.

    EDIT: By the way, this is a 252,000+ mile gasket, no other major problems.
     
    Last edited: Aug 25, 2019
  7. Jason131

    Jason131 New Member

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    Thank you. That would great if I didn’t have to pull the heads and have them resurfaced. Replacing that gasket and flushing the cooling system would be a whole lot less time consuming.
     
  8. Pete fender

    Pete fender Pete Fender

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    On a v6 0r v8, there are two of these gaskets.

    Everyone will laugh at me for this, but it works.
    When checking for aluminum head warpage, use a straight edge.
    If you have .002 or more spaces, try this.
    Find an old tempered glass table top, and with spray glue, attach two sheets of 80 grit sand paper end to end to the glass. Tempered glass has that greenish tint to it.
    Put the head on the 80 grit, and without pressure, slide the head back and forth over the sandpaper.
    A little each time, and eventually, you will be removing the high spots, resulting in a flat head.
    Keep checking with the straight edge.
    You can save a lot of money this way.
    I have even done manifolds and engine decks this way, with other flat surfaced tools and sandpaper.
     
  9. Jason131

    Jason131 New Member

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    It sounds like it will work if you can get the sandpaper to stick well enough to the glass. What is the significance of the glass? Could you use another flat surface? I will definitely try it. I’m hoping I don’t have to.
     
  10. Pete fender

    Pete fender Pete Fender

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    I just use the thick tempered glass because it was available.
    Some people use large planers and circular saw tables.
    I have see old machine shops use large, flat slabs of steel, called lapping tables, and they us lapping compound.
    But, nothing beats a Bridgeport Mill.
     
  11. Pete fender

    Pete fender Pete Fender

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    I found a video of how I've been doing it for years.
    I discovered this method from an older gentleman when I was in high school.

     
  12. 08'MustangDude

    08'MustangDude Profile Violation

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    It is best to use tempered glass because? Almost all the other surfaces
    can already be bent or warped; metal, wood, plastic, are all susceptible to
    bending, or warping with heat and pressure applied. A solid piece of tempered
    glass won't bend or warp, with time, or with the weight of the head running
    across it. You're guaranteed a 100% flat surface.
     
  13. Pete fender

    Pete fender Pete Fender

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    Just make sure it is on as flat a surface that you can find.
    The thicker, the better.
    I piece I have been using is almost 3/8" thick, it was a tabletop.
    Don't push down, just slide the head under it's own weight.
     
  14. Jason131

    Jason131 New Member

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    Is it a waste of time to try some of that Bar’s Leak head gasket repair?
     
  15. Jason131

    Jason131 New Member

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    I know that’s a dumb question but I had to ask it.
     
  16. Pete fender

    Pete fender Pete Fender

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    Barr's used to come in cars right from the factory, but if it is as bad as you say, I think you have a bigger problem.
    If something caused a solid gasket problem, it's doubtful a chemical will fix it.
     
  17. 08'MustangDude

    08'MustangDude Profile Violation

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    It all depends how bad the leak is, how bad the gasket tear or break is. They
    have really fine tuned the product, but they only last 6-months to a year, if that.
    I mean, it's always worth the TRY, but you have to follow the procedure TO THE
    LETTER! I can tell you, not relevant to you, but they DO NOT work right with
    mazda rotary engines. It actually blocks water passages and ruins the motor...

    The decent thing about the 3.8 V6 you have, is it's a PUSHROD V6, so the
    head repair, gasket or replacements are so much easier. You can basically
    just lift the loaded head off, and put a loaded head back on without doing any
    timing, or placing piston #1 at TDC on the compression stroke; like you need
    to do with an over-head cam motor. There is more to it than THAT, yes,
    but easier than OHC heads...

    As far as CAUSED the failure? Other than a faulty gasket, it's age, or misuse.
    If you've over heated the motor, and warped the heads, the gasket blows in
    that area easy. If you use too thick an oil and race the car around, that can
    break at any weak spot. There is no bigger problem with a simple head gasket,
    that alone is a big problem. BIGGER would be if you overheated it, and warped
    the head(s). That's now a HEAD problem, not a gasket problem, the gasket is
    failure is a collateral damage due to physical damage to the head.
     
  18. Pete fender

    Pete fender Pete Fender

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    A chemical can not replace a solid.
    A temporary fix will fail.
    I have seen the results of incorrect repairs over the 30+years I have been a mechanic.
    It only gets worse until correctly repaired.
    The only sensible thing to do is at least remove the manifold and heads.
    You could also pressure test the cooling system.
    But it's your car, I can only advise you from experience.

    If stop leak would fix it, nobody would be selling gaskets and seals.

    A most valuable tool anyone that repairs a car should have.
    It also can be borrowed from most auto parts stores....
    How to Pressure Test a Cooling System in Under 10 Minutes
     
  19. 08'MustangDude

    08'MustangDude Profile Violation

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    Redundant as usual...
     
  20. Pete fender

    Pete fender Pete Fender

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    The only good repair is a permanent repair, with proper parts.