Oil Blow - Flame Trap Clogged? B230FT (940 Turbo)

Discussion in 'Volvo 940' started by NCMan, Dec 2, 2004.

  1. NCMan

    NCMan Guest

    I looked at my wife's engine (B230FT - USA 1994 940 Turbo) today and noticed
    quite a bit of oil around the oil fill cap, and the trail of it running down
    the valve cover and off the back end of the engine. Since I had the oil
    changed a few days ago I figured it could be from a messy oil refill. I
    wiped up the oil that I could reach, then sprayed engine degreaser and
    sprayed it off.

    After driving for ~30 miles I popped the hood and looked at the valve cover.
    Once again oil was leaking around the oil filler cap and runnnig down the
    valve cover and off the back of the engine.

    Thinking there may be too much oil in the engine I checked the oil level and
    there is the correct amount - the oil level is right in the middle of the
    XXXXXXX part of the oil dipstick.

    So I went online and saw the SwedishBricks information on oil leaks and how
    a clogged flame trap can cause it.

    What I need to know is this:
    1) Does it sound like a clogged crankcase breather system?
    1) Does the B230FT (USA 1994 940) have a flame trap? I have seen that they
    have it and also that they do not.
    2) How do I access it? Do I need to remove the intake manifold? Or any other
    parts? Step-by-step instructions with visual aids (diagrams or photos) would
    be helpful.

    NCMan, Dec 2, 2004
  2. NCMan

    James Sweet Guest

    Yes, it sounds like a clogged crankcase vent, no your turbo motor
    *shouldn't* have a flame trap but that's not to say nobody put one in there.
    You should be able to access it without removing the manifold, though the
    oil separated box bolted to the block may be plugged in which case you'll
    have to take off the intake, not particularly hard to do though.
    James Sweet, Dec 2, 2004
  3. NCMan

    Stuart Gray Guest

    More likely the oil separator box has clogged up, does this on high mileage
    turbo and non turbo engines. I changed mine and what a difference.

    Stuart Gray, Dec 2, 2004
  4. That's my prime suspect, too. The box can be removed and reinstalled with a
    modest amount of work (two 10 mm bolts and some twisting and grunting), but
    you will probably need to replace the o-rings on the bottom once it is

    A new one is definitely the way to go. It can be cleaned out somewhat with
    solvent, but I had to dig the deposits out of the upper tube on mine to get
    back on the road. I also had to replace the hose that connected to the top
    of it, since it was plugged almost solid! Anyway, if you try to clean the
    separator, it should feel like a 3/8 inch hole when you blow through it, not
    like a soda straw. (And wipe the oil off your lips before asking the wife
    for a kiss!) ;-)

    Michael Pardee, Dec 3, 2004
  5. NCMan

    NCMan Guest

    OK, that's what I suspected, but hoped it was not. Now for the nitty-gritty.

    I have not done anything like this, but it should be in the realm of my
    average do-it-yourself skills. I am a very visual person (though I CAN read
    <grin>), and would appreciate any pictoral images of the removal process.

    If you know of any good images post the link, and I will get them from

    Yes, I did find the swedishbricks info, but it was all text.

    Thanks everyone.

    NCMan, Dec 3, 2004
  6. NCMan

    NCMan Guest

    I found the hose that goes from the Turbo unit over the valve cover to the
    black box under the manifold. The large hose to the turbo, and the smaller
    hose from a "T" to the manifold, were all open. Dirty on the inside walls of
    course, but still clear of total obstructions.

    From reading the responses the flame box itself can get clogged, so I will
    work to replace that. Didn't see the bolts, since there is so much
    accumulated oily sludge in and around the box.

    Again, pictures will be greatly appreciated.

    NCMan, Dec 3, 2004
  7. NCMan

    grtdane63 Guest

    grtdane63, Dec 3, 2004
  8. The Volvo turbo engines do not have a "flame trap" but do have an oil
    breather. The oil breather is a black box located under your intake manifold
    and can be checked by attaching a length of fuel line hose and blowing into
    it. If you are unable to blow through the breather is most likely clogged
    and must be replaced.If it is not clogged you may need to look at your
    turbocharger. You may also want to check the vacuum hose off the oil trap
    nipple to make sure it is not clogged.
    The intake manifold is in the way but does not have to be removed!
    joseph amitrano, Dec 4, 2004
  9. NCMan

    Tony Stanley Guest

    Strange, that is just like the one the 360s (B200E etc) but different to the
    one on my 95 940SE Turbo (B230FT). Note the item in the picture is not the
    flame trap and is an oil seperator. In my experience this never becomes
    clogged, but all my engines (and most of the ones I have known in other
    cars) all get fully warmed up, get regular oil changes and clogging is not
    an issue. A friend did once get a clogged old type flame trap on a 360
    (coiled foil type, just above the oil seperator) and popped the plastic
    plug at the back of the head spraying the engine bay with oil, but he never
    changed his oil.

    The poster only complains of trickle of oil, the most likely cause in this
    case is a hardened seal on the filler cap (about 2 quid from volvo). Best
    way to check oil breather is to unscrew the filler cap and try to lift very
    gently, it should tug slightly then release when lifted.
    Tony Stanley, Dec 5, 2004
  10. NCMan


    Oct 27, 2019
    Likes Received:
    What procedure did you use for removing the breather box that did not involve removing the intake manifold? Can't figure it out.
    vvan15, Oct 27, 2019
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