A C208 pilot reported a corporate maintenance facility mechanic asked that an intermittent fuel gauge not be entered into the maintenance log because it immediately grounds the aircraft.

Narrative

Our company has been doing regular maintenance on majority of our airplanes. During this week I have got every morning different airplane for use as an add hock airplane for that morning and different airplane for afternoon. On Friday I have got airplane that just come back from maintenance previous day. During the flight left fuel gauge indicator was start showing erratic indications indicating full tank and shortly it would return to normal indication; and normal quantity. This kind of erratic indication continued few more times through the flight. On the way back to point of origin; fuel indications on left side did show normal quantities without any erratic movement. I have research the MEL and planning to defer the instrument gauge; however the fuel gauge was not one of items for deferral. Same airplane had W/B and POH removed out of airplane. Flight had been completed without any further any further incidents. In background after this incident; previous pilot reported that during drop/pick up airplane from corporate maintenance facility; he did reported mechanic problem with gauge but mechanic ask him not to put that item on logbooks (as that grounds airplane immediately) as gauge is showing only intermittent erratic indications.