Hello folks, I apologize for the long post. I recently was given a 2001 9-5 2.3t from a trusted family friend. He had the motor rebuilt (the quality of the rebuild or my friend’s trustworthiness is not in question) after buying it from the original owner who “blew” the engine. He sent the cams to be polished, but the machine shop machined them instead. My friend did not know this until after he had the motor back in and was having slight oil pressure problems. He checked everything else that it could possibly cause pressure problems, but all were fine. So it is the clearance of the cams. At this point, with it being one of many cars he owns he just put 20w-50 conventional oil in it and only drove it sparingly. Now I have the car. It runs great, no flickering oil light, but has a slight hum on first start up in the morning, but goes away after about a minute (it’s not from sludge. Yes, sump dropped and checked, clean. I also have updated the oil breather). I believe it’s from the oil pump pulling up the thicker oil. My question is this, short of putting new cams in, would full synthetic 20w-50 and a larger oil filter help with the morning hum by being easier on the oil pump, keep the pressure up and keep engine lubricated. Thanks for any input and thoughts.