Searched before I posted but it was all threads about the heads of the 2000-2001 xj's. Mines a 95 so I know I dont have the same head as the newer ones. This is what I sit at when at idle. When I first start it the pressure is fine but drops over time

 

How many miles on the engine?
excessively worn main bearings is probably the number-1 cause of low oil pressure..........or possibly some broken valve-train part, but if it runs fine then that's not the case.
Also the oil pump relief valve spring weak, or some gunk stuck in the relief valve, but that is not very common.
You could also possibly have a faulty gauge sending unit.........Easy to change, and not very expensive....................I just changed mine recently as it was leaking oil through it...........It's mounted on the oil filter adaptor housing..........
If you have access to a oil/transmission pressure test gauge.....(some places may rent/loan them) you could verify your engine oil pressure.......
Harbor Freight has a cheap gauge you could buy, and possibly adapt to one of the block fittings.
http://www.harborfreight.com/200-psi...uge-68251.html

Your oil pressure at idle honestly doesn't seem too low though.............According to Mitchell:
Minimum oil pressure should be 13psi@ 600 rpm.
Normal oil pressure should be 37-75psi above 1600 rpm. Oil pressure relief is 75psi.

You would be surprised how little oil pressure an engine can be run safely at................For instance, the LT1 350 V8 in my Firehawk specs the normal oil pressure at 6psi at 1000 rpm, 18psi at 2000 rpm, and only 24psi at 4000 rpm..........

A typical rule of thumb for safe engine operation is 7psi per 1000 rpm...............

What does yours read when you rev it up a little, when it's at operating temperature?

 

That looks like around 15psi which is within spec.

 

Yeah, yours is normal. 13 PSI at hot idle is the norm.

 

Your fine. Do not worry about pressure at hot idle. As long as it comes up with rpm you should be ok. I have 4psi at 650 rpm....been that way forever. Take a peek through the oil fill cap...if oil is flowing you can bet your bottom dollar that oil getting to the rest of the engine. Contrary to what most people think pressure is not a needed function. Lack of pressure is the result of another problem...not lubrication.

 

1. What weight oil are you running?
2. What oil filter are you running?
3. Have you ever knocked the oil pressure sending unit
4. Have you ever noticed any sludge?
5. Does coolant disappear and your oil look milkshakey?

 

Hot oil is thinner so your pressure will drop at idle. As long as your pressure is good while youre driving don't worry about it.

 

x2

 

The engine runs fine so if you guys are saying its in spec im not going to worry about it to much. Thanks

 

And I haven't been losing any coolant or seeing any in the oil so a cracked head shouldn't be in question

 

Mine will drop that low at times when at idle when hot in summer and almost that in winter 10w30 220,000 still runs good.

 

Yes, even below spec of 13psi can be ok. Use your ears if it is running fine it probably is fine.

 

Yea theres no knocks or ticks or any weird noise coming from it so I think ill be fine. I didn't know the hot idle psi was so low. I always thought it should be at least 20 psi... shows how much I know lol

 

That's why we're here--to help each other out.

You can't learn if you don't ask questions.

 

Hope this is not too far off topic.

How long does UV dye for oil and coolant last and remain visible under UV in the engine?