What is "Relief Pressure" on my Jaguar, and what does that even mean? Oil PSi?

(2010-05-30 19:09:26) 1. Wise Talking Cat Named Binky Says: 1985 Jaguar XJ6 4.2L I6

152,000 Miles. Engine in EXCELLENT Confition!

Has "Relief Pressure" of 65Psi, i think...

I put in the Recommended Grade, and i see 40PSI Idling (up from like 20Psi when the engine is Hot with the old, Dead Oil that was in there for OVER A YEAR) .. and 60-65 Psi while Driving around 2000-3000 RPM!!

One of the Jag Lovers people Complemented me, and said it mean my Engine is in -Excellent- condition.

So, am i fine with this recommended "Thick 10W-40/20W-50" in there?

it IS what Haguar Recommends.. im asking what "Relief Pressure" is, and if im fine as i am.

Filter was changed too...2. Whyyyy Sooo Serioussss-A! Says: YOURE FINE!!!3. Country Boy Says: Inside all gear type oil pumps, there is a pressure relief spring. Oil pressure is always higher when it's cold. It's also higher when cold with such high viscosity oil. *Call a Jaguar dealer concerning the viscosity grade that's supposed to be in the car. The molasses you have in it now takes all day to pump to critical frictional surfaces during cold and hot starts. That's where 80% of all engine wear occurs! mobil1 website recommends 10W-30 if the car is always operated at temperatures above 0 Farenheit.

I would like to hear from you concerning your reasoning why you think such thick oil is better for your motor. What additives are better? Tag: What is "Relief Pressure" on my Jaguar, and what does that even mean? Oil PSi?