19
Just realized the hard way that injector return lines can bleed air for days
Was chasing a no-start on an '02 Ford 7.3 at a ranch outside Bozeman, and it took me three days to figure out the return lines were letting in micro bubbles. Has anyone else fought phantom air in the system after replacing just the supply side?
2 comments
Log in to join the discussion
Log In2 Comments
wyattbennett27d ago
Return lines are ALWAYS the culprit when air keeps showing up.
6
dixon.daniel27d ago
Yeah, "return lines are ALWAYS the culprit" is basically gospel in my experience. I've wasted so much time chasing leaks in supply lines or pressure switches only to find a tiny pinhole or loose fitting on the return line that was just sucking air. The thing is, even a small crack can cause persistent air because the return side has negative pressure, so it pulls bubbles in steady. Plus, the water hammer from trapped air can wreck stuff like heat exchangers or pumps if you don't catch it early. Running clear tubing on the return for a quick visual check has saved me hours more than once. Just gotta remember that return issues don't always show as drips, sometimes it's silent but deadly.
2