the oil pressure is fine on my 87 xj6 (slightly low when idling, but rises to 40 with a little gas and around 60 at speed) and the dipstick shows top of the full. the oil light comes on at odd times, but consistently on after 20 minutes of driving. nothing else seems amiss.

I did try reading the other threads and got a ton of very good information, but not sure I could really relate it to this exact issue. i'm game for replacing the sending unit for the light, if I can find it, but I hate to start swapping out perfectly good parts for no reason.

by the way, this board is great, and I hope in 3-4 years, i'll be able to answer someone's question in return. thank you everyone.

 

The oil light sender is the small one on the side of the oil filter housing.

It is highlly suspect in my opinion, as is the wiring in that area.

The switches do fail, and the wiring could be chafed on a metal bracket/strap, and thus supplying an earth path for that light. It is that simple.

 

Make sure you have a correct oil filter with built in by-pass valve.

 

so I replaced the sender with a new one, and the light doesn't come on anymore. However, I noticed the light also doesn't come on when the engine is first started. is it supposed to? (I honestly don't remember if it came on before.)