Low Oil Pressure indication at Idle

[Eric Bromschwig]

My IO-470-L's are now past TBO by about 50 hours or so, and initially on a cold startup, the oil pressure jumps right up the green arc and stays there for the duration of the flight...after landing, however, taxiing in at idle power setting, both oil pressure needles are barely off the 0 peg, and WELL below the red arc.  I'm running 15W50 Aeroshell for oil, and that's been that way the whole life of the engine.  I suppose I could start running thicker oil like W100, but that doesn't really tell me what's going on.  Any ideas?

[Tom Pelz]

Eric,

After your flight and while you are taxing and your oil pressure is low, consider going out and take off again.   Monitor your Oil pressure then.

IF they are within the prescribed limits on take off and at cruise, you are probably ok.

On the other hand, go out and do a full power run up.  While doing your run up, cycle the props.  If the oil pressure fluctuates with the prop cycling, I would overhaul the engines.

How is your oil analysis?

You don't have an oil filter, but have you had anything on the screen?

Tom

[Lewis Gage]

I do not have the overhaul manual for the IO-470L, but most Continental engines are listed as 10 PSI minimum oil pressure for "idle." I would say that would be for taxi or other ground operations that are under 1000 RPM. So long as the oil pressure is in the green arc when the throttle is pushed in it should be OK to fly the engine. Momentary oil pressure drop during prop cycling is normal.

Regards,  Lew Gage

[Jack Feiden]

I have operated an M model through 3 IO470C's.  All of them, when the engines had a little wear on them and were hot, went to almost 0 oil pressure at idle.  I have always been told that if it indicated any oil pressure at all under those conditions that that was normal.