it seems to take a long time for the oil pressure gauge to register pressure on cold start lately... feels like 6 or 7 seconds before I hear a change in engine noise as the oil starts feeding through the engine and the gauge jumps into the middle of its range. This is on my 1990 Ranger with 2.3l engine, manual transmission, 180k miles, original owner, good maintenance on oil changes (3k interval or six months, whichever hits first).

Is this likely a function of the filter leaking down completely overnight? Or does it indicate a more fundamental deterioration of the oil pump?

Thanks for your advice,

Kurt

 

So, I measured the time today... it was longer than I thought for the system to pressurize. It took a full fifteen seconds before the gauge needle popped into the center of the display. Seems like a long time!

KUrt

 

What brand oil filter do you use?
It could just be the check valve sticking open letting the oil pressure bleed down. Before your next oil change put some seafoam in the oil then run it for about 100 miles before you change it to see if that helps.

 

yes, replace oil filter now

Reads like valve is bad, all oil filters have a backflow preventer valve, basically a flap that is pushed open when oil pump is working and then closes when oil pump is off so it holds oil in the main passages for restart

Oil Pressure is the amount of oil NOT being used.
Which is why no oil pressure is bad
And minimal oil pressure, above 6psi, is fine.

Oil pump just provides a flow of oil thru the filter and then into the main oil passages, there is no pressure as far as pump is concerned
As the oil tries to squeeze thru passages and bearing gaps it all won't flow thru, so a Back Pressure builds up at the filter and main oil passage, which is where the oil pressure switch/sender is located.
So oil pressure shows that more than enough oil is being pumped, it all can't be used

High oil pressure is bad, just like high blood pressure.
If oil pressure gets too high then oil can squirt out of bearing gaps which "washes out" the bearing surfaces so they start to wear.

Oil pressure that is too low, under 4psi, can't over come gravity and valve train won't get enough oil so you get ticking noise.