i have a 1998 buick regal LS with the 3800 naturally aspirated. What happens is once the engine gets warmed up, i get a squeal coming from the engine. The squeal sound like a belt slipping or a bearing going out. I have replaced the belt, the belt tensioner, the alternator, and the water pump. This is the oddest part of my problem, when i take off the oil fill cap or remove the dip stick, the squeal goes away completely. I put in a new pcv valve and it still does it. If you put your hand over the oil fill spout with the cap removed, i have manifold vacuum in the valve covers! This problem does not affect the driveability of my car. Also, the squeal is intermittent. Some days it's there, other days it's not. I am at a dead end. If anybody has any suggestions they would be greatly appeciated!