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Discussion Starter #1
So I've had this 2017 ST3 for about 4 days now and I just noticed when sitting at idle there is a fairly noticeable rattling noise coming from under the hood next to the front passenger side wheel. It is exactly the same as this person here

And it goes away when I turn the A/C on and comes back when turned off. Is this normal for the ST? I've only got 303 miles on it and would hate to have to put it in the shop already!


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I'd say bring it to the dealer

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Mine always sounds like that. These are just really noisy direct injection engines. Nothing to worry about I say.
 

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Woah, surprised this came up. Mine has the exact same sound. I have not tried to associate mine with the AC, but is sure varies with engine load, and it's not consistent. Goes away with load, and alot of the time it'll return when the engine is returning to idle. Does not do it at all on cold start. Very odd. Car runs great. Don't want to take it to the dealer for anything, LOL, so I've been putting it off.
 

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Probably quieter when the oil is thick and cold, and once it warms up and thins out, it's more noticeable. It's just a clackity engine. Lol
 

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Discussion Starter #8
But it's not clacking or normal clicking one can associate...it actually sounds like loose metal banging around...but if it's normal.../shrug I guess


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But it's not clacking or normal clicking one can associate...it actually sounds like loose metal banging around...but if it's normal.../shrug I guess
Wholeheartedly agree. It sounds like somethings wrong. It doesn't have a rhythm to it (like it's associated with a firing order or something along those lines), or any other rhyme or reason to sound that way. It's out of place.
 

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My 2016 makes this noise.

It's REALLY unpleasant sounding, isn't it? I first noticed it around 4,000 miles but that's only because I don't ever get out of my car while it's idling like that.

As far as I can remember, my 2015 didn't make this noise. I always noticed the direct injection clatter but this noise is much more... random in it's pattern and really sounds like something is off.




That said, I don't care. Car drives fine, I've got plenty of warranty and I have no desire to deal with Ford service.

I think everything's fine.
 

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Discussion Starter #11
So here is my car that I took a couple of videos of to show the difference in noise.

The first one is with the A/C turned on and how quiet it runs



The second one is with the A/C turned off and the rattle/ring clearly audible...to me it sounds louder than what the vid is showing as well

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Mine has this noise and decided to pop the hood and take a peek. To me it almost looks like its coming from the belt tensioner itself. Mine only occcurs after a long drive, but if I rev it up a bit it will go away for a while so its hard to reproduce when I need it to.
 

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I have the exact same issue with my 17 with about 1,000 miles it's been doing it the whole time. Oddly so mine disappears when I turn on the AC as well I think it has something to do with the pulley tensioners as I read in other threads. people have taken their St's into the dealers even had them swap pulleys and it still continues to make the noise. I rolled up to a 2.0 ecoboost fusion and noticed that his car was making the exact same noise, weird. It's such a horrible sound but people say it's normal, I just want to know what it is.
 

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Got it on my 2014 with 41k. I'm worried that when it comes time to sell/trade, that the next potential owner will think it's a bad rod or bearing in the motor... :(
 

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Any possibility of it being the throw out bearing? They tend to rattle a bit when you're in neutral. Try having someone sink the clutch while your standing next to it listening. Before anyone mentions it, I don't know why the noise would go away when the A/C compressor engages but it's certainly easy to try to rule out the transmission.
 

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Not the throwout bearing; or at least mine is not influenced by clutch placement. The AC influences the sound not because of the AC, but because of the load on the engine. Sometime the slight rpm increase from being in gear and taking your foot off the brake pedal is enough load to make my rattle go away. I've been under the hood in the pulley area on the right side with a stethoscope when I could catch it doing it at idle, and I cannot pinpoint it. My guess honestly is valvetrain somewhere under the valve cover on top. Could certainly be wrong though.
 

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My 2013 has done this for 48K miles. No ill effects. I never did find the true culprit but it is a disturbing sound like a bad rocker arm but definitely lower motor area. I know the balance shaft module is gear driven. Maybe play in the unit. Do not worry, drive the hell out of it! Tommy
 

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Mine does this too. 2015 ST3 with 36k. From what I read in other threads, it's the direct injected motors. LOUD!


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