Oil pressure low don't know why

[Lifepirate]

Oil pressure in my 1999 International 3800 w/ t444e 7.8L turbo diesel engine is hovering around 25psi and goes up to about 50 when I hit the throttle it used to go up to 50 right away. Wondering if this is OK or what I should check

[Scooternj]

Originally Posted by Lifepirate

Oil pressure in my 1999 International 3800 w/ t444e 7.8L turbo diesel engine is hovering around 25psi and goes up to about 50 when I hit the throttle it used to go up to 50 right away. Wondering if this is OK or what I should check

Pull the dipstick and check the oil level.

[Lifepirate]

Originally Posted by Lifepirate

Oil pressure in my 1999 International 3800 w/ t444e 7.8L turbo diesel engine is hovering around 25psi and goes up to about 50 when I hit the throttle it used to go up to 50 right away. Wondering if this is OK or what I should check

First thing I did, she's full.

[Brad_SwiftFur]

Originally Posted by Lifepirate

Oil pressure in my 1999 International 3800 w/ t444e 7.8L turbo diesel engine is hovering around 25psi and goes up to about 50 when I hit the throttle it used to go up to 50 right away. Wondering if this is OK or what I should check

Correct me if I am mistaken, but isn't the T444 engine a 7.3? Not a 7.8?

[gbstewart]

how old is the oil? change it out , off hand I can't remember my pressure, I think it runs about 45psi at hwy, and drops to about 25psi at idle, from what I heard and seen that its normal for oil psi to go up and down, whats important is that its always the same pressures. and yes the t444e is a 7.3 powerstroke
gbstewart

[Robin97396]

That also struck me as odd the last time I drove home. I was idling in the driveway to cool it down and noticed the pressure went way down. It doesn't do that while I'm warming it up on odd weeks, but I think the fully warmed oil just doesn't register the same. Or was yours not warm when you noticed the low pressure?

[sdwarf36]

Thats normal. Cold oil is thicker-cold engine's clearances are tighter that warm oil + warm engines. 25 psi at idle is fine. The faster you spin the pump the more pressure it makes-until the pressure relief valve opens at a set pressure. (guessing your 50 psi.) No reason for it to be any higher.

[Robin97396]

Hmmm, just went and looked at my oil gauge with the engine off and cold and it's reading about 50 now, and it hasn't been running for a couple days. Never noticed that before. Seems fine when running. I usually have about 80 while driving. Noticed the low pressure during the cool down the other day but the engine sounded fine and higher pressure returns quickly with increased engine rpm. Wrote it off to warm and needing changed oil.

[Brad_SwiftFur]

On my 9 Liter IH engine, it was showing over 100 PSI at startup, dropping a little as it warmed up. I don't believe a 131K mile engine is pushing that much oil pressure, but I do believe oil pressure sensors/sending units can fail (my Volvo did this exact same thing). I have procured a new part and installed it just tonight, though the wire was secured with a nut (which did not wish to release) ............................ So, my next task is to crimp a new end on said wire and secure it to the new sending unit. Also, as a vehicle is driven between oil changes, engines can consume oil, the blow-by can supplement the lost oil, giving you a full reading, but the oil viscosity is reduced ... it's basically diesel mixed with oil, thinning it. If your last oil change has been a while, it might be time for it and you can consider having an oil analysis done.