Oil pressure 1999 voyager 3.0L engine

The oil pressure symbol is lighting up and chiming. I just replaced the sending unit and it is doing the same thing. It usually happens when it is stopped and idling but lately it has occasionally occurred after driving for an hour or more while going down the Xway.

Oil is new, filter is new, sending unit is new.
There is a slight oil leak which I can smell hitting the exhaust. Less that an ounce in a hundred miles.

I think I can rig up a gauge to the sending unit port; what should the pressure be?

Any other suggestions?

Anything less than 20PSI on a mechanical guage at any time is a bad sign.

Anything less than 20PSI on a mechanical guage at any time is a bad sign.
Thanks.
The oil icon has not been lighting up this week. Is anyone experiencing any problems with the sending units. I have vehicles from the fifties and never have had problems with the sending units. This year , I have had two; one was leaking the other was just a suspect.
Generally, when I have experienced low pressure , it would show up in the lifters. I am not seeing that here.

While I agree that you usually see other signs when oil pressure is low, I would not trust anything else but a mechnical guage to prove oil pressure. It only takes one bearing spinning due to lack of oil to take out a whole motor.

Found this in a post on another forum:

The 1998 Chrysler Caravan Service manual says on page 9-90:
For 3.0L engine.
Oil pressure at curb idle speed = 10 psi.
At 3000 rpm = 45 to 75 psi.

In previous years the low limit was 6 psi at idle.

While I agree that you usually see other signs when oil pressure is low, I would not trust anything else but a mechnical guage to prove oil pressure. It only takes one bearing spinning due to lack of oil to take out a whole motor.
The dilemma is that short of an oil pump or relief valve , if there is one, any repair will involve removing the engine, unless there is some unique problem common to this engine. At this point I am guessing. I'll run the pressure test and ...

While I agree that you usually see other signs when oil pressure is low, I would not trust anything else but a mechancal guage to prove oil pressure. It only takes one bearing spinning due to lack of oil to take out a whole motor.
The dilemma is that short of an oil pump or relief valve , if there is one, any repair will involve removing the engine, unless there is some unique problem common to this engine. At this point I am guessing. I'll run the pressure test and decide.

Only way to test oil pressure properly is with a known good mechanical guage. That will tell you what the pump is doing. A bad relief valve, which I believe every engine has of some type, will usually fail with no pressure or high pressure. I believe these engines have the pump driven off the crankshaft at the timing cover. The relief valve could possible be accessed externally, but I cannot remember for certain. Either way, anything short of a miracle of the pump/valve failing (which is not common) then the engine will need an overhaul. The only oiling problem that comes to mind to me for the 3.0L engine was upper end oiling/lifter issues. They are not known for other failures in the oiling system.