2008 Sebring 2.4l 67000 miles I'm getting knocking and whirring from engine. on 2008 Chrysler Sebring

I replaced the idler pullies and tensioner also the power steering pump. Had the alternator tested for noise but it's not there. When I take the serpentine belt off and start the motor the noise is all but gone. Could this noise have to do with a worn timing belt? (or tensioner) It sounds like a diesel.

by in Warren, MI on May 01, 2013
2 answers 5 comments
ANSWER by on May 01, 2013
Think about your question! If you take off the drive belt and the noise changes, then that is most likely the problem area. Timing belt and its componets are not affected! Mechanic needs to take a look. Possible crank pulley/damper or other driven componets.
COMMENT by on May 02, 2013
On a hunch I replaced the alternator and the noise is gone. Guess you shouldn't trust what the parts store tells you. I think their machine made so much noise it covered the sound. Thanks for your response.
COMMENT by on May 02, 2013
Glad you got it fixed!
ANSWER by on May 02, 2013
I agree with answer # 1. There is no way it can be inside the timing belt. If you want us to check this out please call 313-562-7022 or schedule an appointment on line at StansGarage.net. I am sure we can diagnose it and give you the answer you need. Larry
COMMENT by on May 02, 2013
On a hunch I replaced the alternator and the noise is gone. Guess you shouldn't trust what the parts store tells you. I think their machine made so much noise it covered the sound. Thanks for your response.
COMMENT by on March 17, 2014
Your hunch was partially correct. The alternator may test as good on the parts store machine because their machine does not put the same amount of tension on the decoupler pulley as there is when it is installed in your car. the alternator itself is/was probably fine. The noise was most likely caused by a bad bearing in the decoupler pulley. They are known to fail and yet so few people, even seasoned mechanics, know of the problem. These decoupler pulleys are replaceable. You can usually find them online for around $45-50, which is a huge difference from the $240-280 you would spend on a new alternator. Maybe the mechanics DO know about this and are charging for a new alternator, but only replacing the pulley for a better profit margin.
COMMENT by on March 17, 2014
Sorry you feel that way! However not everyone is a crook!!! No indication here that alternator replacement was suggested as a repair! You can replace the decoupler,,,,'IF' that is the problem!!!