:banghead
My 318I started making a very loud sound coming from engine. Had my mechanic take a look and thought it was the alternator or tension roller. I had the tension roller replaced before and it was not half as loud as this. Here are the symptoms: When you accelerate it tends to go away. When you release the gas and just coast is when it gets really loud. Also, you can hear a loud hissing sound as if there is a vacuum leak of some sort. One last thing, when you cut off the engine, you hear one last squeal. This is after the rollers have stopped completely. It is also idling rough. I don't think it is a pulley or roller. Could this be the pcv valve (or crankcase vent valve)?
My 318I started making a very loud sound coming from engine. Had my mechanic take a look and thought it was the alternator or tension roller. I had the tension roller replaced before and it was not half as loud as this. Here are the symptoms: When you accelerate it tends to go away. When you release the gas and just coast is when it gets really loud. Also, you can hear a loud hissing sound as if there is a vacuum leak of some sort. One last thing, when you cut off the engine, you hear one last squeal. This is after the rollers have stopped completely. It is also idling rough. I don't think it is a pulley or roller. Could this be the pcv valve (or crankcase vent valve)?