Thread: Crankcase Smoke
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  #6   IP: 207.118.20.35
Old 07-08-2018, 12:23 PM
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capnward capnward is offline
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I can testify that the PCV kit pulls smoke and fumes in the crankcase back into the combustion chamber, and keeps the air inside the boat cleaner. IMO this is a CO safety issue. Your rings may be worn, but the A4 will still run, if less powerfully. I change oil every 50 hours, and add 8 oz of MMO to 3 quarts of new 15w40 'diesel' oil. I also put 2 oz of MMO in 5 gal of fuel. In 2500 hours of operation I have not removed the head or the valve cover. Compression is still over 100 on three cylinders, and 95 on #1. When I remove the PCV I can see a difference in the air quality. If you don't have a PCV there should be a hose from the crankcase side to the flame arrestor at the air intake. If the opening in the side of the crankcase is closed,smoke will exit from behind the flywheel, and from the oil fill tube if the cap is off.
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