Low Oil Pressure?

[Titleist16]

Ever since I changed my oil a few weeks ago it seems that my oil pressure has dropped. I changed from synthetic back to regular oil. I checked my oil level and it's full. My oil pressure used to be at 20psi at idle and now it's at 15psi at idle. This is after I drive it on the freeway. I drive 100 miles a day all freeway at 65-70mph. The motor has 13,000 miles on it and doesn't seem to burn oil. What can I check? What could be wrong? Is that oil pressure too low?

 

[rbohm]

8) what oil filter are you using? many people have had oil pressure problems with fram oil filters. once they get replaced with something like a motorcraft or wix, the problems go away.

 

[Titleist16]

I'm using a K&N oil filter. I've been using these filters for a while and haven't had this problem until now.

 

[Titleist16]

I checked my oil line going to my oil gauge today while the car was idling and it there wasn't any oil in it. When I have my foot on the throttle there is oil in it. Could this be the reason for the oil pressure reading at idle? What do I do to fix this?

 

[rbohm]

8) ok, likely you have either an oil pump going bad, or more likely you have a stuck or bad pressure relief valve, or spring. one more possibility is the oil pump pick up has come loose and is drawing air. anyway you look at it you are pulling the pan and checking the oil pump.

 

[Titleist16]

The oil pump is only 6 months old, I put a new one in when the motor was rebuilt. Where is the pressure releif valve located?

 

[rbohm]

8) the pressure relief valve is located in the pump, but different designs put it in different locations in the pump. usually there is a dorman style plug that covers the spring and plunger. you would have to disassemble the pump to get at the valve though.

 

[Anonymous]

I checked my oil line going to my oil gauge today while the car was idling and it there wasn't any oil in it. When I have my foot on the throttle there is oil in it. Could this be the reason for the oil pressure reading at idle? What do I do to fix this?

There is nothing wrong with the gauge or line. When air gets trapped between the gauge and the oil, it usually stays there. At the higher pressure, the air compresses a little, so you see oil move up the line. It won't affect the pressure readings a lot, just a PSI or 2. Bleed it slightly at the gauge while the engine is idling, if it bothers you. This will let the air escape, until the next time it gets trapped in there again - and it will....

 

[Titleist16]

How can I check the oil pump to see if it is working properly? If the pressure relief valve was stuck then wouldn't I have low oil presure at higher rpm's too?

 

[pedal2themetal45]

What waeight oil are you using ??
If you running a 10/40 or 10/30 when it get hot it well be purity thin and give you a low reading.
Tim

 

[Anonymous]

As was stated, bleed the gauge line. Simply unscrew the fitting at the back of the gauge just enough to let the air out at idle( per the directions that came with the gauge), when it starts to drip oil tighten it back up. at rpm the air doesn't have much effect but at lower pressure it has more. Liquids cannot be compressed but air can. What viscosity/brand oil are you running?

 

[Titleist16]

That's what I was thinking about the air in the line. I'll try to bleed it and see what happens. I am using Castrol 10w-30 in the motor. A friend suggested that it might be due to the oil getting thinner which would give me a lower reading. I bumped up the idle a little and that didn't help much. Hopefully it's the air in the line or thin oil and nothing major I need to worry about.

 

[Lazy JW]

The air in the line will not affect the pressure reading. If you have 10 psi, the air will be compressed to 10 psi, and will transmit that pressure to the gauge. If the pressure increases to 40 psi, the air bubble will be compressed further (bubble will appear smaller) and will then transmit 40 psi.

Don't sweat the bubbles. 15 psi at idle isn't real bad. A different brand of oil may help. I like Havoline.
Joe

 

[gtm1086]

:roll: Did you happen to overfill with oil. Don't ask how I know this, but I can tell you it will lower your oil pressure

 

[63comet]

It definitely could be the oil. My 250 (recent rebuild), was running around 55-60 lbs. at idle and would run a little higher at running speeds. I changed the oil at around 500 miles and due to the fact I thought I had a rear main leaking. I wanted to put in straight 30 weight oil. I could only find 20-50 weight oil at our WalMart,( their brand) so I put it in with a new filter, motorcraft FL1, oil presseure immediately started to drop to 20 lbs at idle and 35-40 running. Immediately replaced it with Valvoline 15-40 and oil pressure back up to 55-60 lbs.