Guys, this is just a guess until T.H. can back up or argue my idea, but when the engine is cold, the oil is also and so it does not flow as quickly, therefore building up more pressure. As the engine warms up, the oil thins out to its normal operating properties, which is a reason I think it is not wise to run the engine hard when it is cold... the oil hasnt gotten everywhere yet and is not to its full lubricating properties. Seeing as how you have a mechanical oil pressure gauge, there is only one thing feeding information to it, which is the sending unit which transfers oil directly to the gauge (or so I have seen in the past). Maybe my guess is WAY off base and I hope Terry comes back because I know he knows what he is talking about, and it would be nice to know if my thoughts on this had any validity or if I am totally talking out of my butt.... because when it comes down to it, I do not know it all... I am not for certain on this info, but I do want to learn and I want to help other people. So don't take these as words of wisdom just yet until T.H. shows up.... but yes, I have noticed that cold engines even with electrical sending units read high on the oil pressure during cold running conditions. Hope this helps or will help! And if not, at least I tried.
