noggin21
New Member
I have replaced primary and secondary filters volvo d2-55 - as i was bleeding the system at the secondary filter i heard a "singing" sound from the primary filter? I perservered and eventually diesel appeared and job done. The engine started immediately but when closed down i noticed the "singing" reappeared for a few minutes and then stopped. I removed the bleed screw and discovered the fuel level had dropped in the secondary filter and needed more lift pumping to restore. The fuel tank is beneath the engine (2 feet or so). Could this be air being drawn into primary filter as the fuel falls back to the tank? Should i fit a gauge to the primary filter to check whether vacuum is being maintained?