Can Spec Oil Press Be This Low?

[TallPaul]

My 2002-2006 Explorer/Mountaineer Hayne Manual lists the oil pressure specification as:

4.0 V6 15psi (103kPa)@2000 rpm

That seem rather low considering in the past Ford oil pressure specs usually were 40-60 @2000 rpm.

 

[2oldtommy]

Every engine designer has a goal of reducing parasitic losses in HP. Lowering the work the oil pump does is one of them. Therefore, lower oil pressure than we have been accustomed to in the past.FWIW-Oldtommy

 

[TallPaul]

Thanks. Nothing says OP has to be all that high, though the old rule of thumb was 10 psi per 1000 rpm. It does not give much margin for when the engine wears an pressure drops though. Maybe it needs some 20w50 to boost that pressure! (No, just kidding.) Of course, actual may be somewhat higher and the spec represents a minimum.

 

[Eddie]

What does the Ford manual state? If Ford sys 15@2000 then I assume that is the minimum safe pressure.

 

[friendly_jacek]

Originally Posted By: TallPaul
My 2002-2006 Explorer/Mountaineer Hayne Manual lists the oil pressure specification as:

4.0 V6 15psi (103kPa)@2000 rpm

That seem rather low considering in the past Ford oil pressure specs usually were 40-60 @2000 rpm.


Let me guess, this is with 5W20 oils specified?

 

[morris]

the first car i had was a salvage yard refuge. it had , what i thought was an oil pressure issue. my dad said that if the oil pressure comes up with the rpm its ok.

 

[tinmanSC]

This is a reasonable pressure for a warm modern engine. My Lexus GS has an idle pressure of 7 psi, and 19 at 2K RPM. Seems reasonable to me. Just remember, when cold this pressure will be much MUCH higher.

 

[pidster]

Originally Posted By: friendly_jacek
Originally Posted By: TallPaul
My 2002-2006 Explorer/Mountaineer Hayne Manual lists the oil pressure specification as:

4.0 V6 15psi (103kPa)@2000 rpm

That seem rather low considering in the past Ford oil pressure specs usually were 40-60 @2000 rpm.


Let me guess, this is with 5W20 oils specified?


This is one Ford engine that was never spec'd for 5w20, even my 2010 4.0 calls for 5w30, and I find it quietest on a 40 grade. Maybe the low pressure is why? Just a guess.

 

[TallPaul]

Right, the 4.0 SOHC is specified to take 5w30 (I have 10w30 Maxlife Synthetic in her right now, BTW).

I wonder why they even have the 4.0 SOHC when Ford also has a 4.2 OHV that has slightly more torque and horsepower, and appears to be rated a couple MPG better on fuel (or is it the massive nearly 4500 lb weight of the 2001 Mountaineer?).

I would be curious if the actual Ford manual states 15 psi. Anybody have a Chilton's manual, what does that say?

 

[mechtech2]

That sounds like a minimum pressure, not normal presure.

 

[MrCritical]

Could volume be more important than pressure?

 

[Eddie]

The bearing must be full of oil to protect. Therefore it is volume that is most important for crankshaft & rod bearings. Hydrodynamic pressure is what keeps bearings from metal to Natal wear and not the oil pump pressure. An oil pressure light is usually set to go on at ~ 7 psig which is the low pressure safety cutoff. Ed

 

[CBR.worm]

We had a mitsubishi montero a few (many?) years ago that idled with the oil pressure gauge on zero when hot. Apparently it was ok. The manual showed that as normal as long as the pressure came up with more RPM.