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Thread: Expansion bottle and other

  1. #1

    Expansion bottle and other

    Hi all, my radiator on my Steak Shadow 582 Gray Top is spitting out almost the entire contents of the tiny expansion bottle (via the little relief hole on the lid) after an hours flight, (Shadows have chemist style bottles). I have tried lots of options, any advice? Air lock perhaps, it used to stay around 1/3 full.

    Also the tall hex nut (mounted on the head) that supports the exhaust on my 582 keeps working itself loose. Should I use locktight?

    Thanks

    Alan

  2. #2

    Expansion bottle and other

    New rad cap? Or polish clean BOTH sealing surfaces in the neck of the radiator and ensure the rubber seals (both) of the cap are in good condition.
    Next look for bubbles (carefully) in the radiator when running. Might have a cylinder head O-ring (the inner one) failing. This can happen after overheating (>100C).
    Dave

  3. #3

    Expansion bottle and other

    Thanks for your reply Dave, I have a new 1.2 bar rad cap as recommended by Rotax, I used to have the 0.9. This issue also occurred with 0.9.

    How do you check for bubbles when it's running? Do you mean ruining the engine with the rad cap off and looking into the radiator, or looking at the expansion bottle with engine running? I did ground run it for a short time and then released the rad cap pressure into the expansion tank, I didnt notice any bubbles in the coolant.

    Also how much coolant is suppose to live in the expansion bottle? It always used to be 1/3 full?

    if the bottle is not required on the 462, could I get away with mine remaining in place but empty?

    Thanks

    Alan

  4. #4

    Expansion bottle and other

    You'd have to try running with the rad cap off, whilst looking in the top (not a healthy activity - try using a mirror).
    Also might be impractical - some engine mounts are loose enough to shake water out of the neck until you can no longer see all of the water surface for bubbles.
    I don't think you'd see anything in the bottle.

    In your case, the point is it used to be okay and is not now. So something has changed.
    If it's ready for a service, I'd be tempted to lift the head and fit new gaskets anyway.
    Does it tend to run hot? Could it have over temped?

    Of course you can run with the bottle empty. Nothing would ever have gone back into the radiator from the bottle whilst it is running, so it might as well not be there.
    Just fill the rad to the top before. It will push out a bit into the bottle whilst running, but you can see how much has come out, and estimate whether this is likely to result in enough loss to interrupt normal flow in the radiator circuit. If all is well, it should suck the lot back into the rad on cooling.

    You've run out of my experience, so it might be worth talking to one of the gurus - Nigel Beale, Kev Dilks, etc...

    Dave

  5. #5

    Expansion bottle and other

    Thanks for the helpful advice Dave, I have got a little inspection mirror, so will give that idea a go next.

    Cheers

    Alan

  6. #6
    Diamond geezer 500 Club
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    Expansion bottle and other

    Two rather silly questions -

    What coolant/CHT temperatures are you getting in lfight where the problem occurs?

    What is your coolant? Water/non water/mix?

  7. #7

    Expansion bottle and other

    Hi, it cruises at around 65/70 centigrade, but hits about 85 degrees during the climb out.

    Never used to have this issue until I changed the coolant, so I suspected an air lock, I drained and refilled again, but the issue is still there.

    Mix is 50/50

    Thanks

    Alan

  8. #8
    not real name 500 Club
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    Expansion bottle and other

    Airlocks can be the very devil to shift sometimes. Just draining and re-filling may simply have re-instated the air bubble and it's easy to wreck an engine if you don't shift it. Run with the cap in place on the ground until you're satisfied, but it could also be a head gasket leaking.

  9. #9

    Expansion bottle and other

    Will do thanks.

    Alan

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