Engine/Transmission (1994 - 1998) Min oil pressure at hot idle

[Bigtoyfreak]

Hey, I have a 96 12v with 60K on it. Cold idle I have 65+psi oil pressure but when up to temp (185 degrees) it drops to 12-15psi or so. I've done a ton of searching here but haven't been able to find an actual min spec for the pressure. I'm using a mechanical Auto Meter gauge that's plumbed into the top of the oil filter housing. Just wondering at what point I need to be yanking the motor out to have a look at the bottom end?



Thanks,

Cory

 

[DogDiesel]

Check LOCATION

The normal oil sender location is drivers side middle of block, there are several plugs available along an oil rifle. Oil pressure is derived from originating PSI, originating flow rate, and restriction variations.

Would check pressure at the oil rifle location first. I suspect there is little restriction from the oil filter housing back to the pan, and therefore you might still be OK, and you can keep some money and possibly could have confidence again in your truck.

Many Cummins have high oil pressure when cold, where the thick oil and tight restictions cause it to go high, and the pressure relief valve keep it from shooting off the gage scale.

I had a 250 Cummins with 120 cold and 95 warm, no matter what we did to the relief valve, and Cummins said run it unless a leak formed. One never did.

Good luck

Wayne

 

[Bigtoyfreak]

The normal oil sender location is drivers side middle of block, there are several plugs available along an oil rifle. Oil pressure is derived from originating PSI, originating flow rate, and restriction variations.

Would check pressure at the oil rifle location first. I suspect there is little restriction from the oil filter housing back to the pan, and therefore you might still be OK, and you can keep some money and possibly could have confidence again in your truck.

Many Cummins have high oil pressure when cold, where the thick oil and tight restictions cause it to go high, and the pressure relief valve keep it from shooting off the gage scale.

I had a 250 Cummins with 120 cold and 95 warm, no matter what we did to the relief valve, and Cummins said run it unless a leak formed. One never did.

Good luck

Wayne

Thanks Wayne. I was wondering if having the gauge mounted there would throw things off. I asked at my local Cummins dealership and they said it was OK to plumb the line in there. I'll move it and check.



Cory

 

[12V Ford]

When I first did my conversion, I had my oil pressure hooked up at the port on top of the oil filter. Then I switched it over to where the original oil pressure sensor was so I could do the twins. I use an Isspro Mech gauge and I found no difference in oil pressures between the two locations. Mine idles at about 21 psi and 680 rpm. I had it idling higher at about 750 rpm and the pressure was about 27 psi. My brothers truck is a 96 and it is 25 psi at idle. When it's cold though, it idles anywhere form 60 to 80 psi. In my haynes book, I think it says 10 psi minimum at idle and 30 psi mininmum reved up.

 

[bgilbert]

I've done a ton of searching here but haven't been able to find an actual min spec for the pressure.

Cummins says 10psi min hot idle. 25psi min hot cruise/load/rated speed. Kinks in your oil pressure tubing and junk autometer z-series gauge will show lower than actual oil pressure.

 

[FordCummins]

BigToyFreak, I have followed your conversion on POR4x4, so I am kind of familiar with your setup. I have basically the same rig, and ran my Autometer sender off of the oil rifle, and the factory Ford sender in the top of the oil filter housing. My reasoning here was that the factory Ford gauge is such garbage that it wont know the difference anyway, since it registers right in the middle of the gauge whenever 8psi is reached in the system. If you are indeed keeping the Ford factory gauges as well as aftermarket stuff, this is one route you can go, and it has worked very well for me. FWIW, my truck runs 95psi cold running, 75psi cold idle, 25-30 hot idle, and 75psi hot running on a 96 12V.

 

[Bigtoyfreak]

Thanks for the info guys. I'll ket you know how it works out.

 

[Scot]

Mine runs 10-15 hot idle and 60 at cruise with 95*+ ambient temps.

 

[Eric_B]

At what pressure does the light come on? I am having the same trouble at hot idle in gear with oil light flickering.

 

[bmoeller]

The basic rule seems to be, you want a minimum of 10#/1000 RPMs.