Hello guys, new user.
1998 T&C 3.8 eng. 186K miles, Had a cooling leak coming from Timing chain cover. Replaced gasket and seals with new Felpro kit, no leaks, but now I have an Oil light coming on when eng is nice and warm, not on initial start up.
When I took the TC cover off I didn't even mess with the oil pump, since there were no issues at the time.
Mechanic friend said I probably missed something on reinstall since it started after the TC cover job.
So did it all over again this weekend, this time I took the oil pump cover off to make sure I didn't have a piece of old gasket in there, nothing, every thing is fine w/pump. And there was nothing wrong with initial install that I could see.
Before 2nd redo, changed Oil press sw. with new one from Chrysler. No joy!
Been using Mobil 10w30, for the past 20000 miles.
Put an aftermarket Pressure gage from parts store at same port switch goes in, and am getting more than the 5 psi the manual states at idle, and in between the 30 and 80 psi @ 2000 rpm the manual says. Now the gauge has what appears hash marks at 12.5 psi, so I can't be precise down to the single psi, but I referenced it with my air compressor putting out 5 psi, and it reads fine.
I keep going over and over the install in my head, but I can't see where I could have missed something, all it has is the gasket, 2 round o'rings for the cooling system, 1 square o'ring for the oil port from the pump and the round o'ring at the sump tube. Someone correct me if I'm wrong!

At the point of looking for a cliff to push it off of, but we don't have those around here...

 

You got me stumped too! All I can think of ATM is that the oil pressure when hot is right at the edge of satisfactory, the high-ish mileage is possibly a clue. Go over any work you have done carefully to see you've not disturbed anything nearby. If ok...
I'd change the oil for a heavier weight from 10W30 to 20W50 to see if the problem of low-ish oil pressure as indicated by the light disappears. OR, if the oil is new, put in some of that thick glop by STP et al., which is just a polymer which keeps the oil thicker at high temps. If this action stops the oil pressure light coming on when hot, it'll be a case of worn mains and big-ends. If the engine gets very "tappety" when hot and it has hydraulic tappets, that would prove the case for a worn engine. (You don't know how it has been used previously, it might have been in a short-journey, high-wear situation, AND you don't know if the mileage indicated is genuine).
All this is guesswork of course, not being 'at the scene' as 'twere. But as a casual observation, a hot idle oil pressure of only 5lbs.sq." seems very low. That # on your gauge seems much more like it.
With an old 'van like this, it's not wise to spend too much money as it just won't be worth it.

Leedsman.

 

Sorry on my behalf, I think that I may have induced some level of confusion. When I said "new user", I meant to the forum, not with the van, on the contrary, we've had her since '01 and 37000 miles. Thru those 13 yrs I've been thru 1 1/2 trannys, 4 oil pressure switches, 2 starters, 1 alternator, etc, etc, etc. On one trip coming home from vacation, about 150 miles from home I noticed a severe drop in power and a lot of pinging when accelerating, dusk was upon us and being that close I just kept going keeping an eye on all parameters. Ended up being a piston that melted on one edge down past the rings. Patched her up with a new piston, and she was up and running. Of course we were supposed to be looking for a new van since then but she ran so well and other things came up that we just kept her running. We've come to the conclusion at work that she obviously was built on a Friday afternoon, before a 3 day weekend. So I know the miles are legit, the problem is that before the TC cover job I wasn't getting the oil light, hence why my mechanic friend thinks it's my fault, but I did the job twice now and I can't see where I could of screwed up. The oil is brand new, so I was thinking along the same lines of using an additive, at least to get it's worth till the next oil change, just didn't know which one. My friend had also hinted at using thicker oil, it might be just a coincidence that I did the TC cover job and she just went over the limit and lost pressure, since I have no leaks from the TC cover at all. BTW that 5 psi limit comes straight out of the Chrysler Service Manual. Best $35 I ever spent on her, from a guy in Detroit. The Haynes manual just doesn't cut it. The engine idles fine and she rides great, barring her age of course, but she has none of the noises you refer to.

 

From all you say, I've a feeling in my bones it's coming to "get shot of it" time, before you start spending megabucks on it. I know it's easy to get sentimental about a vehicle that's been part of your life for so long. If the thick polymer/STP trick works with idle oil pressure, at least you're fixed for now, and makes it more attractive for a PX with something newer. All that knowledge you got from servicing the GV will come in handy too if you buy another.

Leedsman.