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Ticking Noise Coming From AC

Hey folks! I have a noise coming from the interior of my car that is incredibly, amazingly, terribly obnoxious. Not to mention somewhat embarrassing when I have a passenger, and it decides to show off.

Part of the problem is that it’s unpredictable when it will occur. It could go weeks or even months without making the noise. Out of nowhere, it will start up again and continue once or twice day, or even any time I start the engine.

The best way I can describe it is: TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK

A brief pause of maybe 5 seconds…Then: TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK-TUK

If I switch the blowing knob from the driver setting to, say, feet, or dash, it’ll stop for a moment and then resume with the TUK-TUK-TUK-TUK-TUK

After it gets as many TUK-TUK-TUK-TUK-TUKs out of its system as possible, everything goes back to normal. During this process and afterwards, it blows cool/hot air at the correct setting, so no performance issues.

If you’re a musician looking for a car that will help you keep beat, I have the solution for you were with a metronome built right in!

Car in question is a 2006 Monte Carlo - Any possibility this is a relatively simple DIY repair? I’m comfortable with basic tasks like replacing car stereos, speakers, headlights, oil change…If this’ll require much more skill than those sorts of tasks, I’ll likely need to put this repair in the hands of a professional.

Appreciate any insight you all might have on this!

From what you describe, it sounds like a noisy valve in the engine. Have a competent mechanic inspect it. Not sure waht the cost will be, if only a valve adjustment, budget about $100.

Just a few thoughts,

If the noise stops when the AC/Heater fan is turned off, it may be part of the fan rubbing on the casing. My 2010 Cobalt does this occasionally.

If the noise occurs when the A/C compressor is engaged then if may be time to change the serpentine belt or check the compressor for binding. If the noise stops when water is sprayed on the belt while the engine is running a belt change is in order. At 7 years the belt is overdue for replacement anyway.

Good luck,

Ed B

It sounds like it might be the HVAC “blend doors” that control what air goes where acting up (i.e., opening and closing randomly). I have a similar issue with my car occasionally, but it’s not very noisy.

Thanks for the responses! Docnick - The noise is definitely coming from the dash area, but thanks for the suggestion!

edb1961 - It does seem to have a plastic sound to the noise. A co-worker said it might be the actuator - Would that be the same diagnosis?

Thanks 98caddy! Sounds like that’s the actuator then…I replied a few moments ago with a link to an audio file, but it doesn’t appear to have posted…But a quick google search confirms the same noise clicking sounds.

@98caddy nailed it. Not a hard fix. It’s called a blend door actuator. I’ve even seen them go bad on '98 caddys.

Woo hoo!!!

You guys are awesome! Probably saved me $500 of someone hunting down the wrong problem! Thanks!!