Burning a lot of oil but compression test is consistant

Discussion in 'Mazdaspeed 3 General Discussion' started by Mini Franki, Sep 25, 2020.

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  1. Mini Franki

    Mini Franki Greenie N00B Member

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    Hi,
    Im burning maybe 1 liter per 1000-1500km with my speed 3 430hp. I was sure my motor need to be rebuild but when I did my compression test, all numbers are super consistant! But number are a bit high:

    Dry: 200,200,200,200
    Wet: 220,220,220,215

    I have some fresh oil in the intercooler so I know my turbo is leaking but burning much like that? I have a GTX2867r with maybe 175 000km. My car have 168 000km. My car pull hard, I dont feel any power loss. But when I stop the car, I think I can hear a sqeak like if the turbine wheel rub on the turbo housing. I changed my PCV valve 1 year ago

    What you guys think about that? Rebuild the turbo only and that it?

    Thx
     
    Last edited: Sep 25, 2020
  2. Easter Bunny

    Easter Bunny Professional Engineer Platinum Member

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    I would redo the compression test. Unless you have a forged motor with high compression pistons you should see that high of numbers
     
    Easter Bunny, via a mobile device, Sep 26, 2020
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  3. Mini Franki

    Mini Franki Greenie N00B Member

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    I did the test twice on all cylinders and its the numbers I got with max 5 psi of difference. Maybe my compressor tester is offset? But anyway, the important thing is all the mesure are consistant

    I didnt do a leak down test, I dont have the tool to do it. And I cant use my compression tester hose, impossible to fit it on a compressor/regulator. But maybe the problem is here. I doubt I burn 1l of oil every 1000-1500km only by the turbo seal, no?
     
    Last edited: Sep 26, 2020
  4. Awafrican

    Awafrican Moderator Silver Member

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    Seems like a good chunk of oil to be burning from just the turbo yes but you said you have oil in the intercooler so rebuilding the turbo is a good start.

    Also I wonder how your PCV valve is doing, it could contribute to oil consumption if failed IIRC.
     
    Awafrican, via a mobile device, Sep 26, 2020
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  5. Mini Franki

    Mini Franki Greenie N00B Member

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    I did some mod when I started to burn a good amount of oil. I put a filter on oil cap to reduce oil pressure. I changed my PCV valve 1 year ago and put a banjo bolt restrictor on my turbo. Now the problem still and I burn a lot. When I changed my spark plug and did my compression test, I didnt really see oil in intercooler like before. Maybe all the mod fixed the turbo part but maybe now im burning oil from the engine, but compression test is pretty good. Ill do a leak down test, its the only way to know

    My oil become black very quickly, what that mean?
     
    Last edited by a moderator: Oct 12, 2020
  6. jsmith

    jsmith Silver Member

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    Pretty normal.
     
  7. Easter Bunny

    Easter Bunny Professional Engineer Platinum Member

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    The balance shaft assembly holds a quart of oil or so when you change the oil so there is always some.oil left behind and once it mixes it doesn't look like the oil was changed
     
    Easter Bunny, via a mobile device, Sep 28, 2020
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  8. Mini Franki

    Mini Franki Greenie N00B Member

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    Ill rebuild the turbo, ill let you know if its fixed
     
  9. Awafrican

    Awafrican Moderator Silver Member

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    Hopefully that solves your problem

    Edit: I see you had your leakdown numbers posted but edited them out do you want to repost them?
     
    Awafrican, via a mobile device, Oct 12, 2020
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  10. Chris' Garage

    Chris' Garage Greenie Member

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    if the engine is stock i'll put money on the oil rings being carboned up. i was using a quart in 500 miles or so.. compression was good. pulled engine apart and the oil control and expander rings were all gummed up
     
  11. Mini Franki

    Mini Franki Greenie N00B Member

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    My leakdown test was false because probably not on the good TDC for the 2 and 4 cylinders. So I think my exhaust valves was open so that make false results. Ill redo the test when ill put back my turbo. But results for 1 and 3 was pretty good, only 1% of leak. But theorically, if compression test is good, all is supposed to be good no? Leak down is for know where exactly is the problem if compression is not good?

    I use meth injection since long time ago so I doubt about carbon depot problem. But everything is possible!

    After removed my turbo, I dont see any real sign of fresh oil so im a bit worried. I have a little shaftplay but nothing too much. But in dual ball bearing turbo, its hard to know. I sent it to a shop so ill clearly know if the turbo is okay or not
     
    Last edited: Oct 13, 2020
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