[PacificMustang01]

Hello everyone! I know this topic has been discussed a lot, so sorry to post again about it. But I've read all that I can find on the topic and still have questions. So here goes:

First, I've got a 2001 3.8L, runs fine and no knocks or ticks at all. To make a long story stort I installed a mechanical oil pressure guage. I just didn't trust the stupid stock "Idiot Gage" after it has been acting up. Put in new guage using a "T" connector at the oil pressure sending unit on the engine block so that the stock idiot guage at works too. Also changed the sending unit while I was there. New mechanical guage works great, old stock idiot guage goes "on" liike it always did.

Here is my question: What should my oil PSI be at idle? I'm getting about 20-40psi when hot at idel. It goes up to ~60psi when accelerating, crusing at ~1800 rpm. The chilton book specs say that the pressure should be between 40-60psi at 2500 rpm. At 2500 rpm I'd be doing like 85mph, and my pressure is about 80.

Do I need to worry that my pressures are higher (both at idel and 2500rpm) than the specs in the book? I know oil pressure can change due to many variables (temp, rpm, new vs old oil and filter, etc), but is an idel pressure of 20-40 too high?

I have two thoughts that may be affecting my guage readings also. First, there is still a little bit of air in the tube to the new guage that hasn't worked it's way out yet. Might that throw off the readings? Second, could the "T" I used to connect both guages change the readings a little also? I wouldn't think the "T" would do it. But I would think the air in the line would be the more likely cause.

Anyways, thanks in advance to all. I love the forums and my new car.

[jasons_98gt]

sounds to me like your getting good oil pressure...on my 98 gt the chilton specs are 25-40lbs hot at 1500 rpms but i put out between 45-60 at 1500 and above...as a rule of thumb there should be 10lbs of pressure per thousand rpms..as for thinking about high pressure if your vehicle is cold then yea the pressure is gonna be higher especially cruising down the interstate the oil is staying cooler but dont worry if it was a problem your rings woulda blown by now just think of it as better than not having enough oil pressure

[PacificMustang01]

Thanks jasons-98gt. I'm glad to know that someone else is getting higher pressure than specs state. I too agree that I'd rather have the pressure on the higher side than not enough. Also ture that if something was wrong something would have blown by now.

That's why I didn't trust the stock guage. I think the sending unit was bad and every once in a while it would drop all the way down to nothing, then jump back up. A total bad sensor/electrical thing because the car ran fine, and if I really had no oil pressure the engine would have blown.

Seems like the sensors in these cars are kinda crap. I had the infamous DTFE sensor out when I bought the car, causing the MIL light to be on. Because the MIL light was on the little old lady (origional owner) I got the car from sold it CHEAP! I guess she was told by the dealership it would cost like $1500 to fix MIL light problem so she could get it smoged. I scanned the computer, got the famous P0401 code saying ERG system. But, thanks to advice from the forums I knew it was only that damn sensor.

Thanks to this wonderful community!

[jasons_98gt]

yea well alot of people were complaining to ford i guess about the oil gauges fluctuating all the time so they put in the dummy gauge which dont tell you anything but good luck enjoy the new ride

[PacificMustang01]

that's too bad. it would be nice to have a stock gage that actually measures pressure, even if it is not calibrated/have actual numbers on it. Having a guage labled "Oil Pressure" that is bassicly an off-on sensor is very dumb.

Don't people realize that oil guages are supost to fluctuate? I mean damn, people are use to temp guage starting low on a cold start and then increasing as engine warms up.

Makes me wonder, is our voltmeter guage actually measuring the voltage with engine off and with charging? Come to think of it I never see that guage change.

At least the temp guage is a full analog guage, even though it's not calibrated to anything.

[stephen]

The air in the oil line makes no difference. The air transmits pressure the same as oil, also the T won't make any difference.

[PacificMustang01]

Sweet! Good to know. I didn't think the T would matter, but thought the air may do something different, due to it's different compresability......but it makes sense that since it's all in a closed system (air and oil) the entire pressure would be the same throughout the system.

So, I'm not worried about the pressure readings I am getting, but does anyone else get oil pressure readings that are higher than specs?

[PacificMustang01]

Quick follow up to my question:

I have now realized that it takes a REAL long time for the oil temperature to reach what is considered "hot". Most of my driving around town is <25 miles. My coolent temp reaches the normal range fairly quickly (within 10 or so miles), but my oil pressure would remain high, as in my origional post. But I just took a long road trip from San Diego to San Francisco and learned that it takes about 80+ miles for my oil temp to get "HOT". After 80 miles I finaly saw my pressure drop and I'm assuming that this is when the oil is hot.

Although, my pressure is still higher then specs, I'm not concerned about it any more. Once it's "hot" I now get like 70psi at 2500 rpm, and about 25psi at idle (~750rpm). I assume now that the differences from specs are most likely due to differences in gauage calibration (a 15% difference could easily account for this).

So, in case anyone else has ever wondered just because your coolent temp is "hot" it doesn't mean your oil is "hot".

[Onemanzu]

my jeep has a real oil pressure gauge and it always reads 10 to 20 psi above normal until about 10 minutes into operation then it drops down to about normal.

try changing your oil and, i know, run seafoam through it just to help everything out.

good luck with your issues.

[PacificMustang01]

I'm going to change my oil right now Onemanzu. Funny you mention that.

It's just funny that mine is always 15-20 psi above specs, even after 80+ miles and "hot" oil.

Besides it just being a cheap mechanical gauage that could be calibrated badly I was thinking it could be that the last oil put in was 10-30. Manual calls for 5-20. Now, I know this shouldn't make too much of a difference, especially living in san diego where it doesn't get cold, and oil should be aobut same viscosity when hot, but you never know.

I was also thinking the old filter may be cloged,, causing the increase. We'll find out when I'm done changing.

On a side note I replaced the oil pressure sending unit when I installed my mechanical gauage and I haven't had the strange oil pressure needle drop to 0 on start up anymore (the entire thing that scared me into installing a real gauage)......so I'm assuming the old one was bad. It's nice to have a real oil pressure gauage, nevertheless.


keep you posted.