Left Front rattle.....

[split]

My 2013 Fiesta SE Sedan w/dual clutch auto, has a rattle in front of the steering wheel under the hood.
It only occurs at speed > 35MPH, and gets drowned out by road noise at around 60MPH
The noise does not change with speed or RPM
While driving along, I can put it in neutral and the sound does not change..
I can't feel it through the steering wheel or pedals.
Its a fast rattle, not a clunk. It sounds like wind induced rattle from plastic. I have jammed paint sticks into any loose plastic and the sound persists.
I can't find anything else loose.
It seems independent of the road condition.
It rattles independent of engine temp
No issues with steering or struts or CV joints or radiator fan
It only has 57K miles, and looks new under the hood and elsewhere

Is there some common problem that might explain this?

Baffled !

 

[LionsTooth]

Not heard of this, but yeah it must not be motor/gearbox related if you keep hearing in neutral. Did you check the trim around the bottom of the windsreen? Maybe a wiper arm is loose? Sometimes sounds travels around and its hard to pinpoint. Prop the hood and get a friend to ride around on top of the motor while you get it up to speed......never mind!

 

[Handy Andy]

Ever seen this?

You have two, one on each side at the, and just above the, front wheels.
The metal base bolts to the car, the "puck" rests inside it and is mounted to the SHOCK
which is part of the "strut" the Strut is the spring, and shock, the spring pushes up and holds against the metal
thru a 2-piece plastic cup bearing.
The Stock absorbs road noise and mounts to this "puck"
Both are the strut, these two allow the wheel to turn (rotate to steer) but maintains the position as an axle.
The klunk you hear, may be from this assembly ...
the puck can pop out of the base and "float" until the weight of the wheel is lifted so the the puck can reseat.


​

 

[Handy Andy]

See if you have any loose parts hanging down from the dash - it can be many things...

 

[split]

The klunk you hear, may be from this assembly ...​

I don't hear a clunk. Its not from the wheel area..at least it does not seem to be. And even on an absolutely smooth road, I hear it.

 

[split]

See if you have any loose parts hanging down from the dash - it can be many things...

Its definitely outside under the hood.

 

[split]

Not heard of this, but yeah it must not be motor/gearbox related if you keep hearing in neutral. Did you check the trim around the bottom of the windsreen? Maybe a wiper arm is loose? Sometimes sounds travels around and its hard to pinpoint.

The sound is under the hood. Nothing loose in the wiper area.

I have noticed that the hood insulation has fingers near the back of the hood which hold it in place. These fingers are not holding anymore. I suppose it could be the insulation flapping.....but there should not be any air flow back there as there is a rubber gasket sealing the back of the hood to the body.

Was considering covering the grill opening to the radiator with plastic, just to stop any potential wind.....just as a test

 

[econoboxrocks]

The sound is under the hood. Nothing loose in the wiper area.

I have noticed that the hood insulation has fingers near the back of the hood which hold it in place. These fingers are not holding anymore. I suppose it could be the insulation flapping.....but there should not be any air flow back there as there is a rubber gasket sealing the back of the hood to the body.

Was considering covering the grill opening to the radiator with plastic, just to stop any potential wind.....just as a test

Are they broken off? If so, I'd just tape it down and drive it. If it stops making noise, you found the problem.
The car doesn't have any panels underneath to stop air from moving around in the engine bay, so there is air moving around. It may just be vibrating against the hood.
Maybe not, but I'd start there. If that doesn't stop it, it's something else.

 

[split]

Are they broken off? .

No, the fingers are still there, but they pull right out of the hood if I try to put them back in. I doubt tape will stick to that material. Maybe a ratchet strap might work as a test. I'll see what I can come up with

 

[LionsTooth]

No, the fingers are still there, but they pull right out of the hood if I try to put them back in. I doubt tape will stick to that material. Maybe a ratchet strap might work as a test. I'll see what I can come up with

I removed the sound blanket because it wasn't staying in place in the rear clips...I didn't hear any sound difference.

 

[econoboxrocks]

No, the fingers are still there, but they pull right out of the hood if I try to put them back in. I doubt tape will stick to that material. Maybe a ratchet strap might work as a test. I'll see what I can come up with

Can you take a pic and show us?

 

[Handy Andy]

Hmmm...

Well, you have fender plastic wheel wells, and even the front valence - which has a left and right side mount kinda like a splash guard - that bolts the plastic wheel well, to the front bumper skirt/cowl. Uses a T20 or T25 and an 8mm socket for 3 screws - right in front of the wheel. Behind inside the wheel well itself.

If you hit something, this may be where that "rattle" is, broken plastic and the wind pushes it.

The upper portion of the wheel well uses plastic retainers push in rivet types...another spot to check.

 

[donaldjl]

Just saw this. Is it a higher or lower pitch, like something lighter or heavier? Does it sound metallic at all, like maybe a heat shield that broke loose and is rattling around near the cat?

 

[split]

I have ruled out the hood insulation. I inserted a thick card board sheet that extended over most of the engine bay and out into the wiper area. Shut the hood on it. This shielded the insulation from any wind. Absolutely no difference.

Any and all plastics in that area were jammed with wooden paint sticks so that they could not move. This includes the inner fender skirts, valence, radiator shroud, etc.

Its a rattle sound, not metalic, not high pitched. A spinning something with bad bearings could make this sound too, something with constant RPM. But it only happens @ >35MPH and is independent of engine RPM, road condition or engine temp. Noise does not change with speed. Its like on/off. A/C Fan is off. Coolant Fan is not running. In gear or neutral, same.
If I had to guess as to its location, I would put it in the area surrounding the transmission. This vehicle is like new. Not a drop of oil leaking from anything

CV boots look new(but not speed dependent,so not likely). I'm going to get a passenger to try to pin point the noise location from the passenger seat. Maybe we can triangulate it.

 

[Handy Andy]

How about having someone stand outside by the road, long straight stretch of level surface?

It's so you can have them look and see if something is getting pulled down onto the road in the shadow, clean-clear view of underneath between road, wheels and undercarriage underneath the car. Can be a E-Brake cable onto a valence getting caught in the airstream - pushed into the wheel or down to the road.

I come up behind some vehicles everyday that have something like hose or cable dragging along underneath - see it plain as day. I'm surprised they don't hear it, or maybe they've just learned to ignore the noise it makes.

Just some thoughts...

 

[split]

I have been underneath and don't see anything hanging or loose.
We just did the drive and the passenger is pointing towards the left front wheel. I'm hearing it at the transmission at the same time. I feel nothing in the steering wheel, but I'm going to jack it up and check the front left wheel bearing. A wheel bearing at 58K miles?? If the bearing is sourced from China, then yes, otherwise I would bet against it. Also, I just drove it 2000 miles and it was making the noise the whole trip. If it were a bearing, you would think it would have turned to dust after 2000 miles . (UPDATE: Raised the front, wheel bearings seem fine.)

This time I even switched off the engine while in neutral @ 40MPH, no change in the noise.
One other interesting bit is I don't seem to hear the noise while I'm initially accelerating to 35+, I have to back off then I hear it clearly. I have noticed that a few times. As we go faster, the road noise drowns out the rattling....so 35-40 is where I have been focusing.

 

[split]

More data, still no answer.
I now believe something is definitely switching on. If I get up to 40 real quick back off and maintain speed, NO rattle.... wait...wait, what ever it is switches on and I can hear the sound go from quiet to loud(over about 3 seconds) and stay there, all at constant speed. I pulled the fuse on the radiator fan and A/C pump. No difference.

What is on the left side of the engine that switches on or opens up?
All I see is the MAF, throttle body and of course the Dual clutch trans. Everything works, shifts fine, no check engine light.

 

[Calebdrums1985]

Sounds like the transmission shift forks doing their thubg and preselecting gears...does happen between 123 gears?

 

[split]

Sounds like the transmission shift forks doing their thubg and preselecting gears...does happen between 123 gears?

The sound persists even in neutral, engine off, coasting (Dual clutch trans)
But the trans shifting, could be the something "switching on", as it shifts into some higher gear. That would make sense with the notion of hitting >35MPH and then backing off....at that point the trans is likely shifting to a higher gear since the load comes off.

 

[Calebdrums1985]

The sound persists even in neutral, engine off, coasting (Dual clutch trans)
But the trans shifting, could be the something "switching on", as it shifts into some higher gear. That would make sense with the notion of hitting >35MPH and then backing off....at that point the trans is likely shifting to a higher gear since the load comes off.

I know my duel clutch rattles when selecting gears a little. Happens more when your weak on the throttle and brake.