Air in oil line oil heater

   / Air in oil line oil heater #1  


New member
Jan 6, 2024
See pic. That is my current setup that gets air when i bleed it. Less then 1 second of tiny bubbles shortly after i open bleed port. Heater never cycled off for 45 minutes as i bleed it over and over. If the bleed was closed < 20 seconds, then no bubbles, but if it was open >30 seconds, there was tiny bubbles,but for less then 1 second. Several times I had it open for 30 to 45 seconds after bubbles stopped and never saw any more. Until i closed it for 30 or more seconds.

   / Air in oil line oil heater
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Wow that posted all by itself before i finished .


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   / Air in oil line oil heater
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Ignore syphon in fuel bucket. Copper tubing goes into fuel and syphon is not used.
   / Air in oil line oil heater
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Ok on this site line space means add comment. For this test I replaced the pump flare fitting with new. Im always reluctant in tightening for fear of over tightening. It is quite tight, but i could get another 1\4 or even 1\2 turn, but if i turn it any more, ill need to do one full complete turn and i fear that would be over tightening and may be even be possible. I did cover threads with dope and let it sit after tightening for 48 hours before turning heater on. If it is pulling in air it only does for under 1 second. Maybe by opening bleed port im reducing the pressure differential and that stops air from being pulled in. Another words it might be pulling in air continually when bleed port is closed.