My car has a grinding noise, sounds like a bearing when it is first started up. You can't hear it at idle but rev it up a little and it's fairly loud. My tensioner bearings and waterpump are new and the noise was present before I replaced them. I thought that was where the noise was coming from but it doesn't appear to be so. I'm going to check out the alternator bearings next weekend- although it seemed to spin ok when I did the belts. Also, the alternator light seems to stay on a bit long when I first start up - it is charging about 14 volts though. I removed the AC compressor when I replaced the belts/bearings so it also can't be that. Has anyone else had experienced a similar situation. The noise goes away fairly quickly - in a couple of minutes - depending on how cold the engine is. I also thought it could possibly be a heat shield vibrating but it still sounds more like a grinding noise?