Ok, got the jeep about 1000 miles ago, changed the oil with valvoline high mileage 10w30.... Now at 209,000 miles.... 4.0

For a while I was having high oil pressure according to the gauge. Sometimes almost to the top line while driving on the hwy... Is it 80? And idling around 40....
Now I'm sitting at about 20 most of the time, maybe a Lil lower or higher depending on engine speed...
Is this normal? Did something possibly get freed up now that it's been driven regularly? It was parked for a year or 2 before I got it.
Or is this a sign of the pump giving out?
No milky oil or coolant loss... Engine sounds feeakin great!

 

Your oil pressure sender is failing. I'd put money on it. It's a common failure.
Mine read 80 PSI...then one day wouldn't go over 30 or so....then failed completely and started spraying oil out the back.
It's screwed in next to the oil filter- easy to change. Get one from the dealer, or NAPA.

"normal" is no less than 13# at hot idle, rising with RPM.

 

Thanks, that was the other thing I was thinking... Either the sender or the gauge... I'm debating putting in an aftermarket oil pressure, voltmeter, and temp gauge anyway... But then I'd have 3 dead gauges on my dash.
I will be replacing my oil pump in a couple months when I drop the pan though....

 

Why replace the pump?

It's for sure your sender. It will give rather accurate readings after you replace it, and they're cheap. After that, if you notice a loss in pressure/flow, you can consider changing the pump.

 

I'm just going to replace it as a precaution when I pull the pan and replace the rear main.... I'm mainly pulling the pan to clean all the crap out of the motor... I'm going to do the pan and valve cover soon.... I know it's not a fun job, so I'm going to do everything I can at that time.
2 things I'm over cautious with.... Brakes and oil systems

 

I'd add cooling system to the list as well.

 

Well, yeah.... I'm getting the parts together to convert my system.... But that's another can of worms....

 

Ever read this?

http://www.jeepforum.com/forum/f19/4...fixed-1304679/

 

I read something similar, but not the same post. That is why I asked if something could have let loose and now it's working properly in my original post.
When I first got the jeep it seemed to be WAY high... Now it registers within spec.... Just looking for input to see if anyone had heard of this, or if it was a symptom of something else.
I can also add that my blow by issue has nearly disappeared after cleaning the ccv system.

 

Not surprised with the blow-by issue. there is a mod you can make to your valve cover while you've got it off to help with the blow-by, too.

Cruiser’s Valve Cover Mod
Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.
　
Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.

 

Man. You're on top of your shiiiiii.....well you get the idea. THANKS!

 

Ok, well lets hope it's plugged or the sending unit went bad... Now it goes up to maybe 30 when I start it, stays there for a few seconds, then goes down to zero.... And stays there regardless of engine speed..... Actually it dosen't go all the way to Zero... Even when the engine is off and the key is out..... It is at about 4-5. It sounds fine though, oil level is good, and there is oil coating the valve train.
No new oil leaks.... But I did blow a leak in a freeze plug

 

I'd replace the oil sender.

 

I plan on it soon.

 

Just for giggles, I pulled it out and sprayed it with carb cleaner, then tried to clean the hole it goes in... It's working better now, but who knows for how long.
I'll replace it when I get some extra $$$.