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  1. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Sad to state that nothing has been done with the boat - will start dismantling process next month... Sadly standing alone in the winterspot and waiting for a better summer...
  2. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    All cracked manifolds are aftermarket ones and from two different brands - hard to get other in Estonia. We checked the surface and it was straight. We will go first for water flow -pipe by pipe... and hope to find something there. If nothing at all, then for next cracked one in 2025 I will...
  3. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Issue is, that NO ALARMS, NO BEEPS - nothing. Just cracks on the bloody manifold. Temps are fine, water and oil pressure is fine. Old gauges are not too reliable, they have been showing funny numbers all the time I owned the boat. One engine has been from the day one slower to speed up.. After...
  4. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Yes, one for each engine, extra one for genny on the bottom of the boat. We did check the flow while boat was in the water and there was water coming freely, but will physically check them anyway. Both filters were clean.
  5. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Will start the "pipe dismantling" project in November to see, if there are something inside the pipes or water chanelles, also will check that water inlet is clean - filter was and water is flowing, but something somewhere most block the flow. Anyway - IF I will reach to some conclusion, will...
  6. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    End of the shittiest season finally arrived - last few days went for testing under load and all seatrials did not show any differences between engines. I have a feeling that despite the fact that everything was changed between the engines, issue still relies with water flow. Noticed that there...
  7. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Fuel pressure was 34 on both engines. We did not test it under the load, but probably do that as well, engine is less powerful over 2500 RPM, throttle is open way more to have the same speed on both engines. Today's plan is to swap fuel pumps between the engines. PS - those fault codes are...
  8. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    So engine is running and still no cracks, also no culprit found. Plugs are OK (one is not iridium as one was broken and repaced with normal one). Fuel pressure on both engines is same. Two error codes are visible on both engines, no issues seen with sensors or nothing bad sticks out. What we...
  9. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    I live in Europe and I can buy RecMar or Sierra parts here, probably can order OEM as well, but with long delivery and proper taxation... I do not think it is issue with bad quality manifold. It has to be something, what triggers it ( being an engineer, it is simple - either too much heat and...
  10. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    few post up is another video of the crack test prior the sledgehammer test, I have used two different manufactures with same results and all the rest of the manifolds are from RecMar. Sierra is another brand used.
  11. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Nope, boat is still in the water
  12. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Will check tomorrow those too.
  13. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    So - new manifold in place and new hoses installed on both engines - I can not see any big difference? previos video was in 1500RPM and this is idle. Also swapped brains between engines, fuel consumption did not change, still the problematic one consumes more and does not run as smooth as the...
  14. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    I have 6 leaking manifolds to share:)
  15. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Hi I do not have proper tools to open up the manifold :) However, last time I did not see the crack anymore and build a small testsetup in my back yard - video is added. Also got some pipe and will be replacing the hose going to the bottom of the manifold with clear one on both engines, will...
  16. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    We had a IR thermal gun and we compared the temps on hoses and manifolds on idle and on the run - could not see any major differences between two identical engine.
  17. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    next step is to measure fuel pressure and build see-thru hoses for waterflow verification, however manifold is not getting hot from outside... A bit clueless with all that thing...
  18. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

  19. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    ...and all 8 injectors are good, will get the report also when I go and pick them up today. Now is fuel pressure check left and clear pipes to see how the water is flowing... Will change left and right side injectors just to have something swapped for elimination purpose.
  20. M

    2002 5,7 Mercruiser exhaust manifold keeps cracking - 5 times this summer

    Visual crack is always in the same location, will test the one currently in the boat. I do not have all the things on the marine to do this kind of testings.
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