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  1. 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...
  2. 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...
  3. 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...
  4. 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.
  5. 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...
  6. 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...
  7. 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.
  8. 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...
  9. 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.
  10. 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.
  11. M

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

    ECM are not yet swapped Water pump, map sensor, thermostat housing are swapped Both head went to refurbishing after hydrolock and new good gaskets were installed afterwards
  12. M

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

    I took one manifold for testing and it was confirmed that crack is thru the metal and water was escaping. Visible crack is always there. Can take the next one also to the test to verify once more - that job is not too costly I have sea water cooling, so no closed cooling part and head leak does...
  13. M

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

    Sadly exactly the same issue was here in 2015, but the guy never wrote the solution :( https://forums.iboats.com/threads/2003-mercruiser-6-2-mpi-exhaust-manifold-cracks.662180/
  14. M

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

    I can not see the outgoing side of the water as it exits thru elbow and back to the sea. I can only see if water is going to the spacer in my case and to the bottom of the manifold. And I am sure that waterflow is there - manifold outside temp on idle and on the run is similar to other 3...
  15. M

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

    Bilge is dry, I have no leaks on my old Searay :) only cracked manifolds....
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