6.2 Engine Sound

[Razorback]

I know sounds are very hard to troubleshoot in person much less on a message board, but I'm going to try.

This is our first 6.2 engine, but have had several 5.3 engines.

When the 6.2 is under a relatively light throttle load, say 2000 RPMs at 30-50 mph, I hear what might be best described as a very, very, very slight whine combined with an air noise. Somewhat similar to a Duramax Diesel's turbo. It is very faint. Wife doesn't notice it. I think the dealer will think I'm crazy. And it may be normal, but its something I don't hear on my 5.3 Sierra. The radio at a normal volume drowns it out.

It seems like that _maybe_ the noise is more noticeable with 87 octane versus 91, but there's not a huge difference?

Is this normal with the 6.2s and if not, is there something I should check before bothering the dealer?

Thanks
GL


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[kses123]

The transmission has a very light whining sound to it, but you have to listen carefully to hear it. Maybe that is it?

 

[Razorback]

Good point. I know tranny's have a bit of a whine at times, but this doesn't sound like that. I'll listen with that in mind.

 

[nuttkaze]

anyone???

 

[Regency]

Do you have a CAI? Or TBS?

 

[Donnie Yukonie]

Actually i don't think your crazy I think all vortec v-8s make a whine i know mine does

 

[Zed 71]

It seems like that _maybe_ the noise is more noticeable with 87 octane versus 91, but there's not a huge difference?

Is this normal with the 6.2s and if not, is there something I should check before bothering the dealer?

Aren't the 6.2L supposed to use 91 octane at a minimum?

 

[THE YETI]

Aren't the 6.2L supposed to use 91 octane at a minimum?

Supposed to and recommended are two different things.

 

[Zed 71]

Supposed to and recommended are two different things.

Spits or swallows, which one is it ?

 

[Razorback]

First, I know the recommended octane is 91. Wife didn't and we had a couple of tanks of 87 before we got that straightened out.

My 5.3 has none of this whine that the 6.2 has. Again it's very slight and probably not noticeable by a tech. Definitely coming from the engine compartment, most likely pax side. My thought is has something to do with intake.

Oh, no CAI or Airraid (yet.)

Engine develops good power. Right at 3,800 miles now.

GL

 

[clay101]

I run purple farm fuel in my 6.2 might only get 14.2L/100km but not much worse then my duramax lol

 

[my09denali]

Does the sound go away after the transmission shifts? I think my truck does exactly what you describe under light load 30-50 mph but goes away once the transmission shifts. I never really noticed it until I had a tune done. Very well could be from the transmission.

 

[Parthery]

First, only the aluminum block 6.2s recommend premium fuel. If yours has an iron block, you can use 87. Check your VIN code and the 8 th digit indicates which block you have.

I listened for the same noise in mine and just barely hear what you are describing. I think it's coming from the transmission.

Good luck and let us know what you find.

 

[THE YETI]

First, only the aluminum block 6.2s recommend premium fuel. If yours has an iron block, you can use 87. Check your VIN code and the 8 th digit indicates which block you have.

I listened for the same noise in mine and just barely hear what you are describing. I think it's coming from the transmission.

Good luck and let us know what you find.

You sure about that? Aluminum blocks were designed for car applications whereas iron block for truck applications IIRC. My truck has an iron block 6.2 and calls for premium fuel. You can use 87 on any of them, but you will get a ticking eventually. Premium fuel is only a recommendation.

 

[Parthery]

My 2010 owners manual references that premium fuel is only recommended for the Aluminum block 6.2. If you have the iron block, (VIN code F if I recall), then 87 octane is recommended.

I think the VIN code for the aluminum block is "2".

 

[doubletapdrew]

It's from the factory intake plenum. My dad's does it too. They designed it to quiet the intake sound but also makes a slight whistle.
If it bothers you a different intake tube like an airaid jr will get rid of it.