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Discussion Starter #1
About a year ago I bought 2004 ZX5 Duratec somewhat hastily but I loved the car and was in a bind. It is now out of warranty but I have had zero problems with it, and I just got it inspected without a hitch.

Problem is that I knew when I bought it the interior noise was louder than it should be, at least stock. I'm just now getting around to investigating what it is, but I have virtually no mechanic expertise or anyone in real life to help me out unless I take it to an actual mechanic. In neutral it's quiet but when in gear the engine is loud and causes the interior to rattle a little bit when accelerating from a lower RPM. There is no detectable loudness outside the car though, and I'm not sure about inspection laws in regards to exhaust, but it passed emissions and everything when I got it inspected 3 days ago (NY state) no problem.

Basically just wondering what could be making it so loud. For all I know a past owner could have done something to intentionally make it louder, and if so I'd like to restore it to the quiet way it comes stock. Any ideas?
 

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I haven't ridden in a Duratec car so I can't say how loud or quiet they are, so this is just speculation.

I'd imagine it's just normal interior noise. It is not east to combat all the harmonics of a cars engine and road noise at every rpm and road speed. Generally there is some transient response felt through the car, rattles, wind noise, etc. When they assemble and design a car they combat these things by fluid filled motor mounts and gaps and tolerances in panels, a tight door handle won't make noise vs a slightly loose one will.

So your basic step one is to find out if something is loose. Try to localize where the sound is coming from, inside outside, drivers side center passenger side, front or back (we already know inside). Once you have that area narrowed down you should look closer at what is in that area, if it's the center maybe the radio isn't pushed in all the way and is moving around some.

One other thing you have to watch for is, does it change with road speed? If it does then you would look to the tires. Poor balance/alignment can cause interior noise just as the engine can.

It's just one of those things that is really hard to diagnosis over the internet and is a lot easier in person. Maybe you can search the regional forums and find someone to help, which I'd say would be the easiest way.
 

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Discussion Starter #3
Thanks for getting back to me.

But this is like really loud engine noise (sorry if I didnt' make that clear) that would lead me to think it's an exhaust issue. From inside the car it sounds exactly like a car that really needs a new muffler. In fact when I first drove it I thought the muffler needed repair until my stepdad (who wasn't inside the car) asked me what the hell I was talking about because it sounded perfectly quiet on the outside.

But yeah it's that loud, and as for where it's coming from it seems like it's coming from the the front/engine area. I just didn't think it would pass inspection if it was an issue with the exhaust making it loud.
 

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You could have a crack in the exhaust manifold, or a blown manifold gasket on the head. Much of the noise would be muffled on the outside by the extensive exhaust shielding....but might be heard from inside the car.

Is the exhaust system stock? Could be a loud after-market system that is mostly heard inside the car......

Inspections in this state concern leaks, missing converters, and broken hangers. A loud muffler passes inspection, but can still get you a ticket.
 

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Discussion Starter #5
You could have a crack in the exhaust manifold, or a blown manifold gasket on the head. Much of the noise would be muffled on the outside by the extensive exhaust shielding....but might be heard from inside the car.

Is the exhaust system stock? Could be a loud after-market system that is mostly heard inside the car......

Inspections in this state concern leaks, missing converters, and broken hangers. A loud muffler passes inspection, but can still get you a ticket.

That sounds more like what the problem could be, I just don't know how to tell if it's an aftermarket system because it looks stock as far as I can tell, at least in the engine bay. Thanks though [:)]
 

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Inspect the entire exhaust system carefully for broken/damage hangers or other issues that might cause the piping/muffler to contact the body. The fact that it is an interior noise problem thatr does not seem to manifest itself outside the vehicle suggests isolation of the exhaust system from the body is a likely cause. In gear the engine may shift position slightly, causing contact where clearances between the body and exhaust is small.
 

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Engines tend to make more noise under a load whether it's high gear at low speeds, or WOT.

You could have an exhaust leak at the flex pipe, but I'd think the vehicle inspector would've noticed that- maybe not. Things like that tend to puff noticeably at idle.

I'd have to say that Penguin sounds most correct.

Hmmm.. here's another thought, what about an aftermarket air intake? That made my exhaust note much louder. The stock air cleaner is a big freaking foam filled box located in the fender behind the driver's headlight under the plastic inner fenderwell. It's supposed to be a lifetime filter, but lots of people remove it for a replaceable filter- and Ford cancelled the idea in 07. You'll know if someone changed it because the stock filter shouldn't be visible under the hood. Follow the air intake, it should go to a black box just behind the driver's headlight, then down from that box to a hole leading inside the fender. That's the stock set-up, if you still have it.
 

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Discussion Starter #8
well I took it to a mechanic. He seemed pretty perplexed and had never come across the noise before. In neutral the car is quiet inside the cabin but with the hood popped he could tell something was off.

After listening around using a screwdriver as a stethoscope he came to the conclusion it was probably the camshaft bearings but told me to contact a ford dealer and have their repair shop look at it. [:(]

Does this sound right to anyone? I searched the forums but couldn't find anyone with a similar problem
 

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My sister has a 2000 Focus LX, when its a cold start the interior shakes like a mofo and gets pretty loud. You can't even really tell where it's coming from, like the whole cabin begins to shake and makes a loud noise. Supposedly after the car warms up, the noise goes away and the shaking/vibrations stop. I cant confirm that though because i'm not in her car often, and when I am its only for a short trip.

Is that what you're experiencing too? And if you are, im curious to know what has/is causing that.
 

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Discussion Starter #11
Yeah the motormounts are fine though. As for the loudness and vibration it occurs ALL THE DAMN TIME. I'm kinda baffled as to what step to take next. The mechanic said cam bearings but he didn't even seem 100% positive since he was pretty stumped for a few minutes. I might just take it to another shop to see what they come up with... I'm told the cost of replacing the cam bearings is really high because it's likely they'd have to take the engine out to do it, but I found an online tutorial that seems to indicate the engine can stay.

Thanks for the input everyone, I still have a feeling this is gonna cost me though haha. The worst part is that the car technically runs great and it's just a matter of me hating the sound, but it's got low enough miles (30k) that it'd be definitely worth whatever it costs to fix it. I'm just apprehensive to put over a grand into a fix that seems uncertain. [unsure]
 

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A total shot in the dark here but is there any modification at all to the intake system? Meaning is the resonator in tact and all hoses attached well? Is there a filter at the bottom of the MAF tubing going down? Maybe someone put the stealth CAI mod on there and you missed it. Its hard to see for sure. If its quiet at idle outside the car then I doubt its an exhaust leak. Sounds like intake noise to me.
 

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Discussion Starter #13
A total shot in the dark here but is there any modification at all to the intake system? Meaning is the resonator in tact and all hoses attached well? Is there a filter at the bottom of the MAF tubing going down? Maybe someone put the stealth CAI mod on there and you missed it. Its hard to see for sure. If its quiet at idle outside the car then I doubt its an exhaust leak. Sounds like intake noise to me.
I've entertained that idea but anytime I mention it people seem to blow it off, haha. So thanks for makin me feel sane. [:)]

It seems pretty possible though, I think since I'm gonna see my dad this weekend and he's pretty handy with cars I'll have him take a look with me or somethin. He's one of the few people I know with any knowledge about cars but I was never able to get his help since we weren't really talking [limp]
 

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Discussion Starter #14
welp, you were right nole05, motor mounts it is. Second opinions are glorious.

My dad and I took it to a ford dealership and they checked it out and were sure it's a motor mount. Taking it in 2 days to get fixed. So pumped to have a hopefully quiet car again [8D]
 

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Ive had the same issue on my 03 zx3, and Ive come down to the shocks and struts, because the noise is worse and the wear on my tread. I havent replaced them yet but will soon, my car also has 150000 on it and I do all the work on it. Im pretty sure but good luck[wave]
 

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Ive had the same problem, my next step is to replace the springs and struts. but Ive been thru 3 sets of tires. my car has 160000 miles. and the humm is getting louder. the parts are going to cost me around 200 dollars at the cheapest. Ive researched this and have come down to the struts. but the car has a lot of road noise naturally.
 

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I would still check the passenger side motor mount. I have an 06 Focus wagon with a Duratec 2.0. It had a vibrating interior and a lot of engine noise transmitted thru the car, especially at idle. I replaced the right side engine mount and it is much quieter with no more vibration. Put a jack under the passenger side of the engine and raise it until the weight of the engine is off the frame of the car. If the vibration goes away, there's your problem. Even when these motor mounts are bad, they look just fine. The difference between the new one I got and the old one was only a quarter of an inch of settlement in the mount.
 

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I have a 2003 Ford Focus SE with 75,000 miles that has the same problem. When you first start it up there is loud engine noise coming into the cab. I mean really loud. I have had the motor mount replaced which helped with the vibration but not the noise. The engine is quiet on the outside but loud at startup and when driving. My service garage has no idea why the noise is coming into the cab. If you find a solution please pass it on.
 
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