The key here is it making noise or blowing smoke?I would frankly leave it alone nothing wrong with the lower pressure.Years ago I thought I needed more oil pressue too well I ended up with 110 lbs!!! Now unless you are running a all out racing engine 40-60 at cruise and low as 10 are perfectly OK. Around 14 years ago I had to call Chrysler engine hot line about low oil pressure for a 3.0. The first thing said was did it have at least 4 psi at idle No I said it had 7 I was told do nothing as there was nothing wrong with it In retrospect The car continued running with the low pressure for years body went away and car was finally junked witha bad trans