: Low/No Oil Pressure



Aurora By Olds
08-23-06, 10:06 AM
Even with a recent added external (7.5x17inch) oil cooler and rotella 15w40, I still lose almost all oil pressure when the engine temp is up to normal operating range at idle. I still have about 20-30psi down the hwy. It becomes proportionally worse as the engine temp rises, and once it reaches over 200, it drops right to nothing at idle. I dont know how detrimental this is to the engine, as I still believe there is oil flow, but if nothing else it is annoying as hell to listen to the DIC ding and flash when the pressure drops to 0. What can I do? Any ideas?

Ranger
08-23-06, 11:09 AM
What engine? I believe the Northstar (probably most engines) only need/have 3-5 psi at idle.

clarkz71
08-23-06, 11:49 AM
If the pressure was 0 you would hear engine noise. Either replace the oil pressure switch or test the pressure with a mechanical gauge.

Aurora By Olds
08-23-06, 03:10 PM
Its the N*
3-5psi is fine with me, but not 0
And Ive never let it sit there long enough at 0 to produce engine noise...yet. I usually two-foot it at stops, or put it in N and bring the r's up enough to keep about 10psi.

unruley247
08-23-06, 05:45 PM
I've had a oil pressure switch problem for years. If i were u i would check it with a off line tester. That what i did and it was fine.

jss
08-23-06, 06:13 PM
Is there anywhere on the Northstart that Aurora can hook up an oil pressure guage that senses not from the sending unit but from the real oil pressure?

Aurora, until I figured it out I would do EXACTLY what you are doing in ensuring that the oil pressure never drops below what the minimum allowable is.

unruley247
08-23-06, 09:18 PM
I'm going to call my mech in the morn and will have an answer hopefully that evening

Ranger
08-23-06, 09:22 PM
Is there anywhere on the Northstart that Aurora can hook up an oil pressure guage that senses not from the sending unit but from the real oil pressure?

Aurora, until I figured it out I would do EXACTLY what you are doing in ensuring that the oil pressure never drops below what the minimum allowable is.
I think you remove the switch and plumb in a mechanical guage there.

100
08-25-06, 09:59 PM
I have heard a way to clean oil pressure thing in the oil pan by adding 12 qt of oil in a N* or something (sorry that I am not talking very clearly, because I don't know what I am talking about...). When something gets stuck somewhere, the oil cannot build up pressure and you need to clean it. Apparently it is somewhat common to get no pressure for a N*. Well, that is what I have heard. You may want to try this thing. There is a specific procedure (maybe in a TSB) for this, but I don't know where it is.

Ranger
08-25-06, 10:35 PM
What you are refering to is when the check valve sticks open in the oil pump, the Northstar will loose oil pressure. This will happen at idle as well as at higher RPM (not the case in this thread, as I recall without going back and rereading). This is because the pump is above the oil level driven off the crankshaft snout. The cure is to overfill by 8 qts. thus submerging the pump and run the RPM's up to about 4K as I recall. That should reprime the pump and hopefully flush whatever was stuck in the check valve. Not terribly common I don't believe.