I just replaced the catalytic converter on my 03.

Tiny
ANONYMOUS
  • MEMBER
  • 2003 NISSAN ALTIMA
  • 230,000 MILES
I just replaced the catalytic converter on my 03 Nissan Altima 2.5s. The catalyst to this was a whirring noise and my car died. Now that the cat conv. Has been replaced the car starts and drives fine but the whirring noise is still there. I'm not sure if that is enough info, but I would like to know what the noise is and if it is worth fixing.
Sunday, March 24th, 2013 AT 12:09 AM

3 Replies

Tiny
CARADIODOC
  • EXPERT
Catalytic converters don't make noise unless they break apart inside and rattle. Typically a whirring noise would be caused by an electric radiator fan. That should not run all the time; just off and on when the engine is hot. It won't hurt anything if it runs all the time but it will wear out sooner, and of course it had better stop when the ignition switch is off so it doesn't drain the battery. It would be smart to have your mechanic listen to it to rule out anything that could cause damage to something else. If the source of the noise can't be located while the car is standing still, there's a tool called the Chassis Ear that uses six microphones so you can listen to six suspect areas while you're driving. I can describe that better if it becomes necessary.
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Sunday, March 24th, 2013 AT 12:51 AM
Tiny
KIGALID
  • MEMBER
Thank you for the quick response. The noise starts as soon as the car turns on and fluctuates as you push the accelerator. Turns off with the car. The noise sounds like it is coming from the area where the alternator is located.
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Sunday, March 24th, 2013 AT 10:16 AM
Tiny
CARADIODOC
  • EXPERT
I would attack that with a stethoscope. Harbor Freight Tools and auto parts stores have them for about ten dollars or less. Listen right next to the pulleys for the generator and power steering pump, but the bearings in idler pulleys cause more noises than anything else.
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Sunday, March 24th, 2013 AT 9:37 PM

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