2007 Chevrolet Cobalt Rattling

Tiny
PARSONSNR13
  • MEMBER
  • 2007 CHEVROLET COBALT
  • 70,000 MILES
My car started to make a rattle noise when it was idling and when you rev up the engine. They said it was the catilytic converter, so got it changed. The idle rattle is gone, but it still does it when you rev the engine and they can't figure out why. Please help?
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Wednesday, July 24th, 2013 AT 10:41 AM

6 Replies

Tiny
FREEMBA
  • EXPERT
Is the rattle coming from underneathe the car? Or under the hood?

If underneathe the car, raise it on a lift and have someone to rev the engine as you and a partner looki for the sorce of the noise.

Things to check;
The metal cover to the catalytic converter.
The heat shield above the exhaust pipe (they attach to the bottom of the floor board)
Engine and transmission mounts
Exhaust pipe hangers
Muffler
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Wednesday, July 24th, 2013 AT 11:35 AM
Tiny
PARSONSNR13
  • MEMBER
The noise is coming from underneath the hood. It is more pronounced inside the car than out when you rev the engine (don't know if that helps)
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Wednesday, July 24th, 2013 AT 11:40 AM
Tiny
FREEMBA
  • EXPERT
Check these:
the cover on the exhaust manifold.
The belt tensioner (with a partner revving the engine, watch the tensioner to see if it vibrates excessively, causing the noise you hear).
The plastic engine cover
oil dipstick
check to see if the engine moves excessively when it is revved (loose or broken motor mount).
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Wednesday, July 24th, 2013 AT 12:45 PM
Tiny
PARSONSNR13
  • MEMBER
Thanks!
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Wednesday, July 24th, 2013 AT 1:08 PM
Tiny
PARSONSNR13
  • MEMBER
No sound when revving the engine while parked and the sound is definitely eminating from the passenger side near the front of the floor board. When u are accelerating from 20mph and up it sounds like a playing card stunk in a bicycle wheel. Is the best way I can describe it.
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Wednesday, July 24th, 2013 AT 1:45 PM
Tiny
FREEMBA
  • EXPERT
Sounds like a bad wheel hub bearing assembly. The sound increase or decreases with vehilce speed. Try getting up to around 35 mph when the sound is very noticable, put the car in neutral and see if the sound remains (and changes with vehicle speed). This is a good indication of a faulty wheel bearing.

If that's the case, raise that wheel an try shaking it (with a hand at the 3 and 9 o'clock positions and then again with hands at 12 and 6 o'clock). If there is wobble, suspect the wheel hub bearing. However, check for wheel lug tighness and hub center bolt tightness as well.
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Wednesday, July 24th, 2013 AT 4:07 PM

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