new oil pressure reading after change out...

[1974dodgecharger]

Well I changed my oil this past weekend and this is my 2nd time with rotella 15-40 this odd.  In the summer after I changed her she would hold steady at 60psi at startup and immedtiatly go to 55psi afterwards at idle and gas.  This was in the summer mind you in phoenix where temps reach 115 and your car is 100 plus just sitting there.

Now its winter time and I changed her again and yeah she idles at 60psi at start up and calms down to 55psi under gas, but now after warm up she idles at the stop at 40psi and hit the gas she goes back to 55psi and holds steady.

Is this normal?  I didnt have this sceneary last time so its odd to me....

[bull]

You didn't tell us your pressure at idle during the summer after the engine has warmed up. Anyway, you probably already know this but multi-viscosity oils act differently at different temps. The design of a 15w-40 oil is that it maintains the consistancy of a 40 weight when the temperature is warm out and when it's cooler it becomes a 15 weight. This helps the engine get lubed better/quicker during cold weather startups but it will also give you a lower oil pressure reading once the oil warms up. When it's warm out the viscosity starts and stays at 40 weight. Living in Phoenix I wouldn't think you'd really need a multi-viscosity oil since the temp probably doesn't drop below 60 degrees very often.

[1974dodgecharger]

Bull,
Thx for the info.  In summer she does 55 psi also.  Yeah my head was blank when i posted that night......thx again man.

[bull]

Bull,
Thx for the info.  In summer she does 55 psi also.  Yeah my head was blank when i posted that night......thx again man.

Mine too. I wasn't even sure I actually posted the above message until just now.