Oil change low pressure

[Andy Ward]

After a trip towing our 5th wheel for 1000 miles, I changed the oil as I always have. About every 5000 miles. Drained the oil & installed the same NAPA # 7202 filter as before. As usual I put as much oil in the filter as I can with out spilling it to get oil pressure as fast as possible.At start up I waited longer than usual for the oil gage to jump up, it never did,then the low oil pressure light came on.I turned off the motor & checked everything, oil was in. Started it again & the oil pressure came up like it should.
What happen to cause the lack of pressure??

[madmatt]

did you notice if any of your other gauges were inop?

[Andy Ward]

All other gauges were fine. The low oil pressure warning light also came on!

[Jim Brzozowski]

Did you drain every last ounce out of the pan, by tilting the truck? I can only think that somehow there was air inbetween the oil pump and suction tube and it took too long to clear the air and caused a low oil pressure light. When you shut it off it had time to clear and was past the pump suction/discharge port on the pump so everything went back to normal. Seldom happens, but I've heard of it. Anytime you uncover the suction end of the pump during a drain, there's a chance you can get drain out of the suction tube, if that happens and the oil runs out of the tube, when you fill the pan with new oil it gets covered back up with oil, but has trapped some air in the tube. Just one of those things. I wouldn't worry.

[Andy Ward]

I was hoping it was a one time deal. Thanks!