Coolant to turbo possible issue

Discussion in 'Mazdaspeed 3/6 Engine' started by SJones, Aug 4, 2023.

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  1. SJones

    SJones Greenie Member

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    As some of you know from other posts here that I have fitted one of these engines to an mx5

    I got an issue with the engine temp sensor, so I haven't fully ran it for a long period of time.

    The issue I am having is that there does't seem to have any coolant running through the turbo, I have it flowing back to the header tank and it's semi transparent so can see it flowing through, I noticed that nothing was flowing.

    I took the return line off and blowed through the header tank creating a little pressure in the system, it then flows through the turbo.

    The turbo is top mounted and higher than most of the the rest of the coolant system but I would assume that the water pump would push coolant passed that issue?

    Is this probably the case that there is air in the system and I need to do a full bleed through? I did read I needed to run the engine at 3k for 5 min.

    But I would suspect that I wouldn't need to wait for the engine to fully bleed for any coolant to start running through the turbo first?

    I'm going to try and replace the sensor this weekend but any for sight into the issue would be appreciated
     
    SJones, via a mobile device, Aug 4, 2023
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  2. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    If you are top mount then the turbo coolant is the highest point in the system. Need to bleed that air too
     
    Easter Bunny, via a mobile device, Aug 5, 2023
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  3. SJones

    SJones Greenie Member

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    I was finally able to work on the car today, I got the temp sensor fixed and now it starts first time.

    I havent ran the engine too long but enough so the temp gauge is now at the half way mark.
    My concern still is that the turbo is still not getting any coolant unless I put pressure through the coolant refil cap.

    as soon as I lower the coolant feed hose below a certain point it pours out (to be expected) but nothing if its hooked up to the turbo (high point)

    I know the coolant hose normally drops down below the egr to the turbo. So was this setup so it was gravity fed?
    I really would of assumed at this point that running the engine till it was warm would of shown some sign of flow, and with me putting pressure in the system and seeing coolant come out that this would assume that the hose was bled at that point (or at least partially)
     
  4. Sleepy_Pat

    Sleepy_Pat Silver Member

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    Do you have a build thread for the mx-5 swap?
     
    Sleepy_Pat, via an iPhone, Aug 14, 2023
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  5. SJones

    SJones Greenie Member

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    not over here, full build thread over at mx5oc forum
    https://forum.mx5oc.co.uk/t/my-current-project-nc-mps-conversion-now-with-pictures-video/137980 its a long read, be warned

    On a side note, I have been giving this some thought. breaking this down as logicaly as I can.

    1. When the coolant feed line is lowered below the egr coolant line then coolant flows and drains as expected (gravity drain technically)
    so i can assume there is no blockage

    2.with either the engine on or off, if I blow into the radiator cap area then coolant flows into the turbo and exits it.
    searching google says on average a person can blow 2 to 3 PSI.

    3.Researching on the internet a coolant pump generaly creates pressure of 5 to 15 PSI at the pump exit.
    This is more than an average person can blow.

    Assuming that these things are correct, and I am hoping for someone to chime in, but this tends to suggest a pump faliure.

    Strange thing with this is when I pulled the engine the coolant pump was replaced with a new one.

    is this a fair assesment or am I missing something?
    As far as I am aware, the pump is a push pump and pics the water from the rad and pushes it through the block, as the turbo coolant feed line is the first thing that gets coolant after the engine, then I would expect there to be enough pressure here to feed the turbo.
     
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