A new and weird sound upon full stop

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2005_LS_V8

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I have 65k miles on this 2005 V8, the car is new to me since 11/2013. I've changed fluids and put new tires on. Opened up the airbox some in a homemade intake mod. No aftermarket tunes to the engine.

So, the last few days I have been noticing a weird sound when I come to a complete stop. It only lasts a little longer than a second. It reminds me of the sound you get on a car that is 'dieseling', that run on phenomenon where you turn the car off and it clunks around for a few seconds, shudders and shakes and then dies. But this is not that loud or long and it doesn't shake the car. It just goes 'rat-a-tat' and then stops. Almost could be said to sound like a valve clattering.

The reason I ask is I'm thinking about doing a lot of maintenance in February with my tax return money, but don't want to mis-spend if something else needs attention. Next up is back brakes and fuel filter. Then I was strongly considering all new coils and plugs, to make sure those are all good and I'm getting all the stock performance I can get.

Maybe this is a dirty fuel filter or fuel pump getting old? I'm just looking for which systems or parts to direct my mechanic to. I'm not planning to get out there and start swapping out parts in the cold : ) Wondering if anyone else ever heard this sound. It sounds like it is coming from the engine bay, just right of center. Can't open the hood to check though, because it only does it when driving and I come to a complete stop. Does it for one second and then it's gone.
 
Does it do it for one second after you come to a complete stop?
Or, only while still moving, even if only slightly moving?
 
It's just as I come to a complete stop and now that I think about it, I believe it's on the harder stops. Maybe it's low gas in the tank, because I was down to '26 miles remaining' on the fuel readout before I filled up today. It did seem more pronounced today and yesterday. I'll have to watch how it does with this full tank, because on the way home from dinner just now, I don't recall hearing it.

It's definitely not happening while moving, not slow or fast. Only for that second after stop, a little chugga chugga and that's all.
 
I'm no mechanic but maybe something is loose, not sure what, but when you come to a harder stop it's just shaking back and fourth a few times and that's it! But I'm not sure if that's any help at all haha
 
I went out for another trip last night with the full tank of gas and I can't reproduce the problem, so I think that's all it was. I'll use that as a cue to fill up next time. Thx!
 
Resurrecting an old post, but I have the exact same thing happening, and it's not fuel level related. In fact, it's not even 100% reproducible (doesn't do it all the time). But, if I stop at what I consider a typical level of braking I get this sound described above. If I stop real easy, it almost never happens. If I stop hard, it almost never happens. I'm at a loss for the culprit. It seems to be coming from the underhood front passenger side more than anywhere, but that's just my opinion. As the original poster stated, I don't actually "feel" anything, just hear it.

06 with 36,000 miles and everything is original under the hood except for belts.
 
If you accelerate decently hard a little bit before stopping, does it then always or nearly always do the noise? After that, if you accelerate very gently and then stop again does it not do the noise?
 
Maybe a clanking brake pad if it only happens when hitting the brakes for the first time after shifting forward. Light braking might not create enough noise, hard braking might create too many other noises and feelings to notice. After the first braking, the pad is already moved forward
 
FDR said:
Maybe a clanking brake pad if it only happens when hitting the brakes for the first time after shifting forward. Light braking might not create enough noise, hard braking might create too many other noises and feelings to notice. After the first braking, the pad is already moved forward
Click to expand...

High heat degrades the spring tension of the anti-rattle clips and rust can cause the brake pad “ears” to bind

OP needs a brake hardware kit. If rotors are still in good condition, could have them turned or just put new pads on along with kit, which consists of shims and the rattle clips. Clean sliders, lube and put back together. Use new rubbers if needed.


I suspect rattle clips. Pads wear down, clips get too close to rotors, touch on vehicle weight shift.


~ but hey! WTH do I know. (just did brakes on the 03 LS8) (band-aid to prove it)


EDIT - - - -

Should have seen the down to metal rear inner pads! Not good!
 
Wait ... is bike70 not referring to the first post's statement of ...

'dieseling', that run on phenomenon where you turn the car off and it clunks around for a few seconds

yeah, brakes don't make a run-on dieseling sound.

OK, confused, I'm done!
 
G-RELL said:
thinking spongey caliber?
Click to expand...

that would definitely be a big problem...

personally, I only prefer my caliber to be large... like at least near a half of an inch or better, it just so hard to beat .45!:shifty:
 
BigRigLS said:
Wait ... is bike70 not referring to the first post's statement of ...

'dieseling', that run on phenomenon where you turn the car off and it clunks around for a few seconds

yeah, brakes don't make a run-on dieseling sound.

OK, confused, I'm done!
Click to expand...

No, but something sliding/rolling from back to front could. It's a long shot, but not much else makes sense here (unless I'm not understanding how the sound is being described.)
I've had a slight version of this before. It was a rock that a kid left in the passenger door pocket.
 
LOL, my aftermarket lug nut remover rolls around in the drivers side door pocket on the 04 LSE, catches me off guard sometime. What's that noise? I meant to wrap it in something.
 
I couldn't help but see a similarity to my cars current issue. You can read my recent post. I first noticed a loose sounding rattle/clackity clack/knock sound when stopping and thought it was possibly a loose piece of splash guard or plastic trim. Maybe it was a rock rolling around in the engine compartment? It seemed to only happen when coming to a stop as well but after some time this is what I was able to gather.

1. The noise happens at around 900-1k rpm and only around that narrow rpm band.

2. The noise happens on deceleration as well acceleration. On acceleration was not as noticeable and is easy to miss because of car/engine/road noise and the fact that I would move through that rpm band quickly. I had to find a quiet piece of road and accelerate kinda moderately slow to hear it but now that I know it happens I'm able to hear it fairly consistently.

3. The noise happens in park. With the car running and in park I can very lightly/slowly raised the rpm to around 900-1k rpm and bingo there is the noise! If I hold it at that rpm it will make the noise continuously but once the rpm drops below or raises above that rpm band the noise goes away.

4. The noise seems to come from left top of the engine

I took the car to Ford and without removing engine parts they feel it is the Cam Phaser. They used the "Car running and in park" test and disconnected the electrical connection to the VCT solenoid that controls the Cam phaser and they said the noise went away.

I hope that what I have learned in some way helps you.
 
BigRigLS said:
High heat degrades the spring tension of the anti-rattle clips and rust can cause the brake pad “ears” to bind

OP needs a brake hardware kit. If rotors are still in good condition, could have them turned or just put new pads on along with kit, which consists of shims and the rattle clips. Clean sliders, lube and put back together. Use new rubbers if needed.


I suspect rattle clips. Pads wear down, clips get too close to rotors, touch on vehicle weight shift.


~ but hey! WTH do I know. (just did brakes on the 03 LS8) (band-aid to prove it)


EDIT - - - -

Should have seen the down to metal rear inner pads! Not good!
Click to expand...

OK, I guess I should have elaborated a little more...I bought the car 2 years ago with 22,500 miles on it and the front brakes and rotors were replaced by the dealer I purchased it from. Unfortunately, they (Toyota/BMW/Audi/VW) Dealer likely were not familiar with the LS (took it in on a one-owner trade), so they didn't install the "rattle kit" for the brake pads if I recall correctly from the dealer repair invoice). I had my local Ford dealer take care of that as it was under the 6 month warranty I had from the purchasing dealer. So, in any case, the brakes and rotors are still quite new. It's been making this noise for quite some time, never getting much different. I tend to not think it's brakes related, as the sound doesn't seem to be that "low" and seems more in the engine area.
 
Wabel said:
I couldn't help but see a similarity to my cars current issue. You can read my recent post. I first noticed a loose sounding rattle/clackity clack/knock sound when stopping and thought it was possibly a loose piece of splash guard or plastic trim. Maybe it was a rock rolling around in the engine compartment? It seemed to only happen when coming to a stop as well but after some time this is what I was able to gather.

1. The noise happens at around 900-1k rpm and only around that narrow rpm band.

2. The noise happens on deceleration as well acceleration. On acceleration was not as noticeable and is easy to miss because of car/engine/road noise and the fact that I would move through that rpm band quickly. I had to find a quiet piece of road and accelerate kinda moderately slow to hear it but now that I know it happens I'm able to hear it fairly consistently.

3. The noise happens in park. With the car running and in park I can very lightly/slowly raised the rpm to around 900-1k rpm and bingo there is the noise! If I hold it at that rpm it will make the noise continuously but once the rpm drops below or raises above that rpm band the noise goes away.

4. The noise seems to come from left top of the engine

I took the car to Ford and without removing engine parts they feel it is the Cam Phaser. They used the "Car running and in park" test and disconnected the electrical connection to the VCT solenoid that controls the Cam phaser and they said the noise went away.

I hope that what I have learned in some way helps you.
Click to expand...

This is interesting. What you describe is very much what I'm hearing with my car. I will try to do the same tests that you did but I think mine does the same.
 
bike70ride said:
... they didn't install the "rattle kit" for the brake pads if I recall correctly ...
Click to expand...

Gotcha, so not the brakes as I earlier suspected but then corrected myself after rereading the very 1st post.

Just as a note: The "anti rattle vibration clips" are part of a "brake hardware kit" ... the LS has little notches on the ears of the pads themselves, the rattle clips have a little dimple, these are often not ligned up or seated correctly by some DIY'ers and when not aligned in the notches, the clips themselves like to run along the very top edge of the rotors. Applicable only to the front brakes on the LS. They also serve purpose as low pad warning indicator.

If you're like my wife, whom drives with the tunes cranked pretty much from start of ignition to shutdown, the last point above is considered null and void.

~ She a bit nutty that way.

Anyhow, good luck, hope you find that annoying noise, I know it would drive me crazy. I always notice them and always have to find them.
 
So I payed special attention to the noise last night as I drove home from work. Here's what happens.

If I come to a relatively slow stop, as I'm down to maybe 10 mph or so, right before the tranny shifts into low gear, (tach around 800 rpm) I hear the "chugga-chugga-chugga" noise and then it drops into 1st. Don't feel a thing and if I stop more abruptly it often doesn't do it (maybe because the tranny shifts down faster?). Other than that noise, my tranny shifts great, no hard shifts or clunky reverse engagement. I have never had the fluid changed, and I doubt it has been done by the previous owner. (The car was always serviced at the local Ford/Lincoln dealer per the Carfax history and due to the low mileage and very consistent service history thru the years, I have no reason to believe they brought it to any other service shop.) I had a notion to call the previous owner's dealer and see if they could release all the service history they had on the car, but I have not done so...and not sure that they could even legally do that?

Anyway, just the latest update I have. I'll have to try and record the sound if I get a chance.

Thanks!
 
You are the titled owner of the car now. You can get the full Ford service records. Even independent shops (if they subscribe) can get that info from Ford's network.

A full transmission fluid exchange is a good idea (except at a quick lube place), and it doesn't cost an outrageous amount. (Not because of this noise or any other problem. Because you have no transmission problems right now and you want to keep it that way.) You are probably not due on miles, but you are due on time.

How about this (on the noise). Get up to the right speed to start stopping from. Shift into neutral and then stop at the same rate as causes the noise. If there is no noise, then maybe it was engine/transmission/driveline related. If the noise is still there, then probably not engine or transmission.
 
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