Metallic whirring/rubbing sound
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Metallic whirring/rubbing sound
Sound just started a few days ago, best I can describe is a metal object spinning and coming in contact and rubbing another object, very similar to the sound a circular saw makes when cutting wood. Only happens on cold starts and when I turn it off and on again, the sound is gone or goes away in a few seconds. I tried to isolate this morning, and when looking from the front of the car into the engine bay, it appears to be coming from the left side.
Any ideas?
Any ideas?
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If you let it idle to warm up, does the sound disappear after ~30 seconds?
If so, then I bet it's your air pump. The air pump injects air into the exhaust stream when the exhaust is still cold to accelerate the heating of the catalytic converter, as it isn't efficient until it's reached operating temperature. This is an emissions control device only, and doesn't run once the cat is hot.
The solenoid and/or the pump itself can both make strange noises.
If so, then I bet it's your air pump. The air pump injects air into the exhaust stream when the exhaust is still cold to accelerate the heating of the catalytic converter, as it isn't efficient until it's reached operating temperature. This is an emissions control device only, and doesn't run once the cat is hot.
The solenoid and/or the pump itself can both make strange noises.
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