'07 Gt/cs Knocking From Dash After Cold Start

EleanorGTCSSavior

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I have a 2007 GT/CS with 130k miles. Randomly usually after getting gas, the following day on cold start there will be a loud knocking noise coming from the dash. I believe behind the radio. This happens every now and then, not every day. And usually after I get gas 87 octane. I don't think it's the blend door actuator as far as the knocking sound because my ac/heat works fine, blows hard and out of all vents. And it never knocks then. Only cold starts. It knocks only like 5 or 6 times and then stops. So it's hard to capture on video.

This is the sound it makes View: https://youtu.be/WZW_-HNSRAw
 
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RaggedGT

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If a MOD sees this, please change title of the thread to 07 GT/CS knocking from dash on cold start.

Thank You
Done. Also,you should be able to edit your own thread titles..Wish I could offer some insights on your issues. My only suggestion would be to scan for codes,even if the cel isn't on-there me be some codes logged that haven't set a light.
 
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racerraj

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Mine knocks. Pretty sure it IS the blend door actuator just trying to tweak the position. Mine started doing this in 2007, I figured something would quit soon after. But it still hasn't, and it doesn't bother me because I know it isn't something that will leave me stranded. When it finally quits, then I'll replace it.
 

EleanorGTCSSavior

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Why is it that I can never get help in these threads? Seriously thinking about trying a different forum at this point.

Thanks for your reply. But I thought the BDA is only if you have issues with your AC/Heat blowing and only in defrost mode? Also, it usually knocks when the air is on for that person, but not my issue? You still believe it's the BDA? Thanks!
 

RaggedGT

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Just for clarity. Is it only after getting gas,like the next morning it makes the knocking sound?
Have there/are there ant evap/emissions codes stored in the computer?
Does the car ever smell like straight gas?
I know a smart guy who is very good with diagnostics,recommendations etc.
I'll put out the MattSignal. He may stop by when he has time.
@74stang2togo
 

MustangIIMatt

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The guy in that video is overthinking it slightly, but that's not a terrible DIY method to figure it out.

If it was me, I just set the blower speed to low, then turn the temp knob slowly through it's full range. If the knock/pop show up doing that, it's the temp door actuator. If not, I move over to the mode knob.

On the mode knob, make sure to start in defrost, and work slowly through the settings. If it starts popping/knocking, make sure the LED on the recirculation button didn't illuminate. If it did, stop, and press the recirculation button to see if it pops or knocks again. If the recirculation button doesn't cause the noise to reappear, it's the mode door actuator. If it does, it's the recirculation door actuator. The video posted by @acutron42 shows where all three are, the guy in the video just doesn't name them by name.

They're relatively cheap, even at the dealership, and easy to install.


You get less help in the S197 section of any given Mustang forum because far fewer S197 owners are DIYers. When I bought my 2010 GT in 2010, I was shocked and appalled to find that 90% of the discussion was about cosmetic bull:poo: and which shops and dealerships they had working on their cars. It was a big culture shock coming from the Mustang II and fox-body sections. It has changed quite a bit over time, as the cars age and find their 2nd and 3rd owners, but it hasn't gotten to the point of their being nearly as DIY-involved as previous generations. Part of that is because these cars are so damned reliable, (except for my 2009 GT/CS, but that's another story), part of it is because they're considerably more complicated than the generations before them.