Oil pressure issue.....
okay, 7 months ago I was hauling *** to work, 78mph, just created a hill, and my oil pressure light came on. Needless to say I crapped myself, hit the shoulder, and shut it down and checked the oil. Full, thin, but full. So I restarted, and no light, so I started off, then light flicker, then no light, then exited freeway and light. So I pumped into parking lot and coasted into a spot. Let everything cool off, at lunch I threw a quart of Lucas into it and gingerly drove home at 50mph, which is about 2k rpm I think? Anyway, never happened again, I changed the oil and filter , put 15w 40 chevron delo In and all has been good. So blew the xk8 last night( long story for another forum) do this morning I hop in the discovery and head towards work, same hill, same spot.........
oil light. Dive over, there’s full oil, so I added another quart, start it up, runs 4 mins, oil light again, stop, restart , oil light off then on again after 1 minute. So I stop, restart, repeat in neutral maintaining 30mph for a couple miles to work.

my question.... why is my oil light a function of time? Once it’s on, it stays on. Ignition off then restart and it’s off for a duration dependent on heat it seems? At lunch I drained the oil down to below full just to be sure I’m not aerating the oil, but still similar behavior, regardless of rpm. Anybody ever experienced this?

 

might be a faulty oil pressure sensor

 

probably, but when it first went haywire this morning i could hear the oil starvation in the lifters, so it's more than that, sort of like concurrent issues, there"s some level of switch wonkiness, but it was definitely preceded by a real physical flow issue. Maybe a 'slightly off' oil pump coupled with higher temp/lower viscosity oil conditions. it's just frightening as hell with a 23 mile crawl home from work. I ordered a pump rebuild kit so i'll get an answer soon enough this weekend. an oil light at 3000 rpm will definitely get your attention.

 

Before you throw a bunch of money at this problem have you looked at the pick-up screen? It's the most overlooked. If the pan was glued to the block with RTV then that's where I'd be looking. The obvious is the sender and normally it will leak. Hard to get to, hard to see.

 

Yes on Pickup tube what ihscout said. Pull the pan and check that the pickup tube is not clogged, loose, or that the gasket isn't missing between the pickup tube and block. I have seen an O-ring placed in place instead of the gasket material gasket. When the O-ring gets old it cracks and when your filter is plugged the O-ring will get pulled into the pump and break up it may then plug up oil galley's if the pieces are larger.