HELP?? 2000 Silverado making funky noise when heater or AC is turned on??

:confused: :confused: HELP....single gal here in need of some guidence....my 2000 silverado started making an real odd noise yesterday, sort of a whoosing noise like something is either hung up in a fan or rubbing, the noise backs off until its almost gone when I shut the fan control to the heater/ac off....Goober and Gomer came to the conclusion that its the timing chain which I don't buy at all, one suggested its a lifter, I don't think thats it either, its more towards the front of the engine, near the the fan and the pulleys with the drive belt on them. Could it be the bearings in the alternator or in the fan to the heater/ac? Is there a clutch to the heating/cooling system? Any help would be greatly appreciated. The truck has 230,000 but has been well taken care of and needs to make it another year before it goes to the bone yard:crying:

The cooling fan is connected to your engine's water pump through a viscous clutch that will firm up when the engine coolant temp gets too hot and turn the fan faster. This is probably what is making the whooshing sound. Sometimes you will hear the fan noise when you first start the engine and drive away while it's still cold....it'll whoosh for a few secs then get quiet.

I'm not sure on your truck but some might have a small auxiliary electric fan that is turned on when you turn on the a/c or defroster. This is a distinctive sound as well and doesn't change with the engine's revs. You will hear it click on and off...especially in traffic on a hot day.

Finally there's a magnetic a/c clutch that connects/disconnects the compressor to the serpentine belt when you turn on the a/c or defroster. Not typically a whooshing sound when bearings are failing though...

You don't mention when this happens...when the engine is cold or hot or both. Does it sound the same at whatever a/c blower speed you set? Hope this will help your thinking...timing chain and lifters being the culprit sounds like hogwash to me too.

Hey there, you are a sweetheart for answering and providing some much information....I really appreciate it! ITs the AC, I unplugged it and the noise stopped completely, I don't want it got completely out and ruin my drive belt in the process, I can handle no AC thru the winter and get it checked out in the spring. It was making the noise when the engine was hot or cold and when I turned the AC/heater fan on it hesitated and then started making this noise that sounded like a plastic sack was hung up in the fan, bearings is my guess or maybe the compressor, or the clutch. I am just relieved to figure it out, Goober and Gomer were so healpful with the lifter and timing chain therory, both terribly expensive to have replaced, that sort of hacks me off, they assume I am a woman and therefore I don't have a clue what goes on under the hood of my truck...ha ha.....I am a very femine woman but I raised two boys all by myself and if it broke, I fixed it or we fixed it together..yes I can run a wrench and know more about motors and tools then any woman I know, plus its cheaper to fix it myself if possible! One of my first attempts was carb kit on this old car I had...ha ha, when I thought I had it put together right I realized I still had a coffee can full of parts leftover......but I tried! More women should! Thanks again for you help!

You're welcome. Ayup, the AC compressor will make quite a racket when it's crapping out. But it is used when you turn on the defroster to blow warm DRY air to defog the windows. Wish I could say that replacing it was easy, but I can't...it's pretty involved and typically requires replacing other contaminated components in the AC lines as well to remove all the compressor pieces from them, pumping down the system with a vacuum pump, recharging, and checking. Not impossible, but think twice about tackling it...for a few hundred extra you can have a pro do it and usually get a warranty.

I'd hook up a AC manifold gauge to see if the system at least still holds a charge and if the compressor is working at all. If everything else is good then maybe just a compressor, orifice tube, and accumulator replacement would be needed.

Again, you're welcome. Good luck!

It could just be a clutch, what engine do you have? If it is a V8 the A/C compressor has its own belt that you can take off.

:confused: :confused: HELP....single gal here in need of some guidence....my 2000 silverado started making an real odd noise yesterday, sort of a whoosing noise like something is either hung up in a fan or rubbing, the noise backs off until its almost gone when I shut the fan control to the heater/ac off....Goober and Gomer came to the conclusion that its the timing chain which I don't buy at all, one suggested its a lifter, I don't think thats it either, its more towards the front of the engine, near the the fan and the pulleys with the drive belt on them. Could it be the bearings in the alternator or in the fan to the heater/ac? Is there a clutch to the heating/cooling system? Any help would be greatly appreciated. The truck has 230,000 but has been well taken care of and needs to make it another year before it goes to the bone yard:crying:

with the a/c or recirculate controls off and the climate control is on in heat mode...you don't hear any noises I would say the a/c belt,idler pulley,or even the a/c compressor is the problem...

the a/c idler pulley is a common problem...as well as the a/c compressor clutch bearing..

this is hard to see and get at on the passenger side front of engine as low as you can go for mounting...have to remove the shields to get access...

it is possible these shields are missing then these problems would be more likely to occur..
GOOD LUCK