On my 2004 Ranger with a 3.0 when idling my oil PSI drops to around 7-10 AFTER its been running for about 20 minutes. What are some things I should check. I just changed the oil and there is plenty in there. Should I do a compression check on each cylinder?

 

Cylinder compression has no bearing on oil pressure.
Are you running an aftermarket oil pressure guage ?
If you're sure the reading is correct , either the engine bearings are worn , the oil pump is worn , or you need to change to a different brand / weight of oil .

 

Did you do the oil pressure switch/gauge mod? You gauge shouldn't move at all since it isn't a real gauge. It only has two indications that work, zero and middle. It doesn't have a pressure sensor. It is only a switch that comes on a certain PSI and makes the needs show normal. If you are getting fluctuating reading other than middle or off, you probably have a gauge problem.

 

I have an aftermarket guage. I dont know how good the reading is I have had the gauges about a year. I noticed the drop when I changed to Penzoil Platinum but since have switched back to Mobil 1 and it has not gone back up. Could the Cam Sync have anything to do with it cause I think thats what caused my old engine to lock up.

BTW: This is my second engine

 

If it was the cam sync , if would fail completely and you would have 0 oil pressure.
Does the pressure increase with RPM's ?

 

One other thing just came to mind.
Has the engine been overheated much ?
If the problem is low pressure throughout the RPM range , you may have sludge built up in the return oil ports causing oil starvation at the pump.The oil is staying in the top of the engine and not returning to the sump fast enough.
Does the guage fluctuate when driving ?

 

Yea when I am cruising at about 3000-3500 RPM's it is about 35-40 PSI I dont know if thats low or not. Engine not overheating and it does not fluctuate.

 

Has the engine been overheated much ?
Maybe you didn't catch the question.
If it was overheated much in the past , it may have caused sludge to form in the engine.

 

The engine has never overheated. I have a buddy that owns a shop I might have him look at it. He does not charge me much.

 

Just pull a valve cover and take a peek at the return ports.If they're gunked up it might be a good idea to pull the oil pan and check the intake screen to the oil pump.

 

I guess I will do that the next day I am off. Thanks for your help Ken.

 

My 3.0 has like 60 PSI at 3000 RPM and like 18-20 at Idle. So yeah, Id say thats a tad low, but not really low enough to worry about. I'd just keep an eye on it. The general rule of thumb is to have at least 10 PSI for every 1000 RPMs, so you need 10 PSI at 1000 RPM, and 30 PSI at 3000 RPM.

 

I don't know if this helps much but my Evo has 24PSI oil pressure at idle. The most I have ever seen it is 85PSI when I'm boosting hard. I installed a simple oil pressure gauge from autometer.

 

What kind of oil filter did you use? Frams have been known to cause oil pressure problems, I installed one on my Volvo 1800E years ago in a pinch, and the oil pressure dropped to 1/2 of what it normally ran. Intalled a Volvo
filter (which I normally use) and the pressure went back to where it normally run.

I'm a believer in using the MFG filters, Volvo on my Volvo, Mann (German OEM Mercedes) on my Mercedes, and Mototcraft on my Fords.....

 

I have a motorcrap filter on there.

 

Well last time i checked car makers made cars not filters and oil so I'm sure the "OEM" stuff is crap.

 

Correct, but the auto manufacturer specifies what the parameters should be for the filters their suppliers build for their engines.

Just like Motorcraft spark plugs, there is a separate part number for 2.3L, 3.0L, and 4.0L Ranger engines. In the case of Bosch, NGK, or Denso, there is
only 1 part number called out for all three engines. So, with the Motorcraft, your getting an optimized heat range plug.

 

Eh. I have had good luck with the aftermarket stuff.