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Knocking noise when at stop light.
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Author:  TrailMix [ Tue Dec 04, 2012 9:12 am ]
Post subject:  Knocking noise when at stop light.
66 Dart... When I'm at a stop light, sometimes I hear a loud knocking noise in addition to the sound of motor. It's only when I have my foot on the brake and am at a complete stop. If I take my foot off brake and inch forward in the car the noise stops. The brakes seem like they work fine at the moment. I'm not 100% sure, but it sounds like noise is coming from right in front of the steering wheel.


Not sure what kind of brakes I have, I know the Dart had a couple different options.... hopefully I can get the wheels off later today to take pictures.

Any advice or insight is appreciated, thank you.

EDIT: It has been doing this since I bought car a few months ago. I drive it every day. Although it doesn't always make the noise... Only sometimes.
Author:  Danarchy [ Tue Dec 04, 2012 9:33 am ]
Post subject: 
check your Torsion Bars & bushings (maybe?)
Author:  mattelderca [ Tue Dec 04, 2012 10:26 am ]
Post subject: 
Hmm... things that make a knocking sound when the car is at a COMPLETE stop. Not WHILE you are stopping, correct?

I think you should be able to rule out brakes if the above are both true.

So, what would knock at a stop? Does the knock go away if you shift to neutral? Manual or automatic trans? I assume auto but you know how that works.
Manual could be clutch, auto could be loose torque converter bolts. It could also be something easy like a motor mount.
Author:  TrailMix [ Tue Dec 04, 2012 10:32 am ]
Post subject: 
Auto trans, Sorry forgot to mention.

I'm almost positive it's when I'm stopped and not when I'm stopping. I haven't tried to switch to Neutral or Park but I will try that.
Author:  Doc [ Tue Dec 04, 2012 12:19 pm ]
Post subject: 
My guess is that something on the engine/trans is hitting on the chassis while stopped, at low idle speeds.
Does the "knock" sound align to any slight engine mis-fire, at low idle?
If so, it's time to check engine mounts, trans mount, exhaust pipe, oil pan, etc for proper support & clearance to the chassis.
DD
Author:  Slanted Opinion [ Tue Dec 04, 2012 12:27 pm ]
Post subject: 
I'm betting on the exhaust system...
Author:  ValiantBoyWonder [ Tue Dec 04, 2012 12:49 pm ]
Post subject: 
i've had an exhaust pipe rattle against the edge lip of the gas tank. it could be anything. i'd suggest blocking the wheels and putting the parking brake on while the car is in drive and visually inspecting the car. BE CAREFUL!

i usually go down to the supermarket and put the front tires up against the parking stops and make sure the car is facing a wall. i put a spare tire between the wall and the front bumper, this way, if the car jumps the parking stop it'll run into the wall. just don't get in front of that sucker!

if the knocking will not show itself, then play with the idle a bit. bring a friend along and have them sit in the car with their foot on the brake and the car in drive. rev it a bit, sometimes it'll make things more noticeable.
Author:  TrailMix [ Tue Dec 04, 2012 1:06 pm ]
Post subject: 
I'm having my exhaust system checked out as I write this. Ill make sure I ask him about it. Unless he notifies me first! Thanks for the heads up.
Author:  Doctor Injector [ Tue Dec 04, 2012 11:24 pm ]
Post subject: 
Does the sound happen 1 time or more than once while you are stopped ?
Is it something in the trunk, like a body ?
Author:  bcschief [ Wed Dec 05, 2012 4:41 am ]
Post subject: 
Broken flex plate or loose bolts ( crankshaft or torque converter )

Brian
Author:  wjajr [ Wed Dec 05, 2012 4:52 am ]
Post subject: 
I too think that something is making contact when engine squirms or torques around when in drive with brakes on.

Have someone hold brakes while simulating approaching stop that generates noise, and observe how much the engine moves around on its mounts, and if the mounts are deformed or cracked.

My car had an occasional knock only when backing out of garage down a small grade while turning steering wheel, it sounded just like a main barring noise. Engine has an uneven pronounced lope in gear when stopped. Long story short I had dimpled one of the header tubes to clear top of power steering gear adjustment nut, and it would only make contact when backing out. This took several seasons to figure where I’m solo, that is no second set of eyes hand. After replacing worn sagging engine mounts, and shimming driver’s side mount 3/16th inch higher did the knocking stop, and proper clearance from adjuster nut was maintained under all conditions.

Another knocking/clunking spell began suddenly when stopped in drive sounded somewhat like barring sound developed after a nonstop 100 mile run after recent transmission R&R; it was loose converter bolts.
Author:  TrailMix [ Wed Dec 05, 2012 6:37 am ]
Post subject: 
Alright, I took to exhaust shop and the mechanic said he's 95% sure it's not the exhaust system. I asked him when the car was finished and he said he didn't see anything, but he put it back on the rack said then told me "its probably not the exhaust"...

So that leaves me with:

-Torsion bars & Bushings
-Broken flex plate or loose bolts ( crankshaft or torque converter or loose converter bolts)

hmmmm, I'll have to look into both of these. I have a Valiant service manual, but are these bolts difficult to get to?

The problem is, the noise is not consistent and surely doesn't do it every time I drive. Someone asked if it's one knock or continuous... It's def a continuous thing. When it happens when stopped and brakes are all the way pushed in.. "knock, knock, knock, knock." ... (Doesn't align with any misfire.... Low idle? Perhaps.. It does seem like it idles low)

And just for clarification, it's only when I stop at a red light will it randomly do it....Then I'll accelerate and get to a stop light 2 miles down the road and there will be no noise.. So frustrating! Thanks for the suggestions!
Author:  mattelderca [ Wed Dec 05, 2012 8:01 am ]
Post subject: 
Next time it's knocking, try a few things that will help track it down.
Shift to neutral,
Raise the idle a bit while keeping the brake on and it is still in gear,
Shift to reverse,
And then see how the noise changes.
Or better yet, take a passenger along and have them jump out and open the hood when you here it and have a look around. It will surely be something loose or touching something else. As mentioned, it could be worn mounts allowing the engine to move around at a low idle or vibrate something.
Author:  Mroldfart2u [ Wed Dec 05, 2012 9:42 am ]
Post subject: 
I am still thinking in my head its flywheel/converter related. Altho a hint to the TYPE of knocking noise will help narrow it down.

A side note:

My Volare has a "noise" (for lack of better term) at easy highway speeds. It SOUNDS like the light metallic tap of a fan nicking the shroud. I can let off gas it goes away, I can accelerate it goes away, only steady easy higher speed cruise does it make this sound. I have not investigated it as I cant get it to duplicate setting still and havent found anyone fast enough to run along side of me with the hood up..... :wink: lol I DO know the mounts are shot because they are "drooping" some on both sides. When spring gets here and IF i am still using the car I will invest in the mounts and see if that is the problem. ( I never think to look closely at the shroud etc when checking oil/water etc :? )
Author:  TrailMix [ Wed Dec 05, 2012 10:37 am ]
Post subject: 
Okay everyone, thanks for the help. Got a new muffler put on this morn, mechanic relooked over exhaust system and said it wasn't the case....

BUT... It started to happen out of the blue again on the way home... I know it's unsafe to be on a phone while driving, but I snapped a quick video...

In the video, the knocking is already happening when I hit record.. I take my foot off break at about the 3.5 second mark for about a half a second and then when I take my foot of brake again at the 5 second mark to move forward at light, you'll notice initial "knocking" noise vanishes... I hope posting a link isn't again forum rules...

http://www.youtube.com/watch?v=MVyxoPQI ... e=youtu.be

Next time it happens, I will try shifting in and out of neutral, reverse and park and taking note if any change occurs.
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