A few months ago, I notice a rattling noise under the hood when my car was placed in reverse or drive. It wasn't too annoying and thinking that it was a fan belt, I figured I'd eventually get it fixed and kept driving the car. Recently, the noise has gotten out of control and I decided to take a look under the hood with my son's father in the car switching the gears. I noticed that the belt vibrates making a loud rattling noise. Yesterday, I drove the car to AutoZone to have the belt identified and purchase it to have a mechanic replace it. The AutoZone technician advised me that my problem is not the belt, but instead a Nissan part - the A/C compressor. She states that the clutch in my a/c compressor is slowly going bad. It is causing my engine to jitter and thus creating slack in the belt which is vibrating and making noise as a result. I recently changed the front right motor mount (75,000 miles) and she states that with the amount of jitter that the engine was doing, I may have need to change all of the motor mounts. I only changed one, because the Nissan dealership indicated that was the problem when I took it in for service once before. At (68,000 miles while still under Extended Warranty) the crankshaft position sensor and CAM sensor was relplaced as they caused my car to stall and the gears to completely lock up. I am also having some other problems which I will list in a different complaint. Seems that others are having these same problems: http://www.consumeraffairs.com/automotive/nissan_altima.html

I have Nissan Altima 2005 model and i am not sure how much i have spent. you can imagine as a start 'i have changed my alternator'... whenever i start my car and put on the A/C after 10 minutes of start up, a weird rattling noise comes from car. From outside its like screeching noise. on looking in to the same, i saw my fanbelt vibrating and this only happen when i put on the A/C.the car is normal when the A/C is off. however the A/C is working in very good condition. i had shown my car to Nissan Showroom Agency where they advised to change the Alternator... the alternator was changed and the noise stopped which lasted for 3-4 days. i lost full trust on the agency and went for retail agencies who are much experienced enough.. i was told that my alternator bearing is not good and was told to change it..then fanbelt...and then fanbelt of one size less and then came my spark plugs....there were other expenses but it was because of wear and tear but this noise is just driving me crazy..... could any one share me a solution what i could do for this?