Engine Noise Coming Through Stereo Speakers

[email protected] · November 14, 2009

Howdy,

I have a '02 Silverado LS 2WD standard cab, short bed w/5.3 - all stock with 146,000 miles. Recently I began hearing a high-pitched whistling/whining/whirring sound coming through my radio speakers. The pitch varies directly with engine RPM, and it comes through the speakers regardless of radio volume, whether it's on AM or FM or CD - even with the radio off! The radio and speakers are stock and I've never modified any wiring on my truck. I replaced my alternator thinking that was the issue but I still hear it. I assume the interference is coming from my ignition maybe? I have about 70,000 miles on the plugs and wires but have the original coil packs - are these possibly to blame? I'd replace these but hate to spend any more money if it doesn't fix the noise. Let me know what you think I should try in order to alleviate the problem.

Aside from this I'm proud to report that this truck is by far the most reliable vehicle I've ever owned. Thanks for your help!

Blake

Nytemare · November 14, 2009

Could be your plug wires...But I doubt it, they're pretty cheap if you want to change them to be sure.

It sounds like you have a bad ground somewhere, and its putting a signal on your electrical system.

Clean your negative terminal on the battery, (and the positive as well seeing as you are there), and where the ground wires attach to the body/frame. Also, any of the ground wires coming from the engine to the body/frame that you can see. Once clean, you can coat them with some dielectric grease.

You were on the right track with the alternator, it does cause this issue sometimes.

Once you have done this let us know if you still have the problem, and we'll try some other things.

Oh and BTW...welcome to GMTC

jrod332 · November 14, 2009

I had the problem but I have an aftermarket stereo. I ended up installing some ground loop isolators on the rca's. Im not really sure what you can get for stock radios. I would suggest checking all the grounds in your truck. There could be a loose or dirty ground, or a ground loop.

Check this out at crutchfield

http://www.crutchfield.com/S-9Qs7bsSdcIc/p...ise-Filter.html

or you could make one.

http://n4maa.us/alternator.htm

[email protected] · November 15, 2009

Nyte,

Thanks for welcoming me to the forum and for the suggestions!! It may be too early to tell for sure, but I got under the hood today and cleaned and tightened up the negative and positive battery terminals, and the noise went away for now. I've heard it come in and go out before so I'll confirm later this week after driving it back and forth to work for a few days.

I'm embarrassed to admit I spent $150 on an alternator when the solution was a turn of a wrench, but at the time I replaced the notorious upper intermediate steering shaft, I didn't have a wrench or socket small enough to loosen the terminal cable bolts (as a precaution against accidental airbag deployment per my repair manual), so I had to loosen and tighten them with pliers (not a good idea I know, but got in a hurry!). The sound started not long after that. After a trip to the store to invest in some smaller sockets and wrenches today I *properly* cleaned/tightened the terminals and so far so good.

Sometimes it pays to start with the simple stuff first! I would be more mad at myself about spending the $$ on the alternator, but at 146,ooo miles I just chalk it up to preventive maintenance.

Strangely, you'll notice I joined this forum two years ago but this is only my second post. I love this forum but I've had so few problems with this truck I haven't needed to post yet until now! This forum saved me a few bucks in Oct. '07 when I got a "lean - banks 1 and 2" SES light that only came on in certain temps and went away after the engine warmed up. A quick search of the forum revealed that the solution was as simple as tightening bolts on my intake to the proper torque setting and it went away for good.

Thanks again!