The Cessna 120-140 Association Forum

I have a C90 and when I start the oil pressure stays zero for about 90 seconds before rising. Once it rises it moves to the 40-45 psi and stays there throughout flight. It was cold today but I have a oil tank warmer I had all on night and the oil was warm to touch when i checked it. Is this normal?

Check this thread, might be what you are seeing....

viewtopic.php?f=7&t=1269

My C90 comes up in 10 or so seconds, usually sits at 30 during idle, goes up to 55-60 during takeoff when the engine is still 150F or so. Comes down to 45 when the engine temp is 180F-200F. I also use a oil heater but it still takes a few minutes to go from oil at 100F to normal operating temperature.

What oil are you using?

I had the same issue. Luckily for me, it was a bad gauge.

Thayne:
Does your engine have an oil filter? 90 seconds is a pretty long time. If the oil is draining out of the filter, that could be the reason; the pressure won't rise until the filter is refilled.

I flew again today and first startup oil pressure started rising in 30 seconds and it reached 30 in about 90 to 120 seconds. After 90 min flight i shut down to refuel, restarted and this time oil pressure rose within ten seconds but it snapped up to 30 psi like the gauge was sticking but worked normally during taxi to hanger. What would cause the gauge to stick? is it minor or major?

8466 wrote: ↑Thu Feb 04, 2021 3:51 pm it snapped up to 30 psi like the gauge was sticking but worked normally during taxi to hanger.

Why don't you think 30 is where it belonged?

The pressure line from the engine to the gauge could be filled with gummy oil. I have disconnected it from the gauge and ran the engine for a few minutes until clear oil runs into a cup.

That or disconnect both ends and blow carb cleaner through it with the straw

thanks my amt agrees.