Metallic fan sound when engine is cold?

SIGOPARK

MEMBER
2016 CHEVROLET SUBURBAN
5.3L
V8
4WD
AUTOMATIC
134,500 MILES

There is a metallic fan sound for approximately 25-30 seconds when the engine is started up. It is louder when on sides of the vehicle versus the front.

What can this be and is it an easy fix?

Sunday, August 21st, 2022 AT 7:36 AM

2 Replies

SIGOPARK

MEMBER
2 POSTS

I have an audio file and will get it on video the next time.

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Sunday, August 21st, 2022 AT 7:37 AM

JACOBANDNICKOLAS

MECHANIC
108,254 POSTS

Hi,

Most commonly, that type of sound is the result of a loose heat shield. If I hear it, I should be able to tell.

When the engine is cold, metal contracts, so it will be looser. When it gets hot and the metal expands, the sound may lessen or go away.

Do me a favor. Take a rubber mallet and tap on the exhaust when the system is cold and see if you can recreate the sound. Also, when it's doing it, see if the sound is from under the car.

Let me know. Also, I attached two pics below of heat shields on your vehicle. Each exhaust manifold has one and there are two under the vehicle along the exhaust. See if that is where the sound comes from.

Take care,

Joe

See pics below.

Images (Click to make bigger)