2007 Mustang knock or exhaust leak?

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Hope this video works...

2007 Ford Mustang 4.6L 87k miles, solid maintenance since I purchased 2 years and 32k miles ago. When cold I get the noise in the video, it is definetly in the lower part of the engine, it almost sounds like it is coming from the transmission. Car runs smooth and strong, I hope this is an exhaust leak (fairly common on these engines). Open to all opinions.
 
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Do you have a smoke machine? Smoke test the exhaust and you will see if there is an exhaust leak.
 
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Does the sound improve as the engine warms up, as in get quieter?

Sounds a little too deep to be an exhaust leak , might be a lower end issue imo.
 

Barkleymut

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I do not have a smoke machine. May get one since this noise concerns me.

It does improve and is barely noticable when outside temps are above 80 F.
 
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That sounds like a mechanical knocking noise to me. An exhaust leak is more of a ticking noise (VERY common on V/6 Mustangs from this era) that gets noticeably more pronounced when you accelerate the engine from idle.
 

Barkleymut

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That sounds like a mechanical knocking noise to me. An exhaust leak is more of a ticking noise (VERY common on V/6 Mustangs from this era) that gets noticeably more pronounced when you accelerate the engine from idle.
This is a V8, and the noise seems to almost go away when I accelerate. However it is hard to tell when sitting in the drivers seat since this car is not quiet. Was tempted to get the wife to gently accelerate while the car was up on ramps but we just had a fight and I didn't feel like trusting my life to her at the time.
 
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Sounds like normal piston slap? Both of my modulars do this when cold. My 123k mile 4.6 and nearly 240K mile 5.4.. Both are whipser quiet once warmed up. I pulled a hill with my 5.4 towing and was over 4000 RPM for 3 or 4 minute straight. When I got to the top I couldn't even tell the engine was running it was so quiet!

I do hear an exhaust leak as well - either one of the manifold/gaskets or the donut gasket is leaking.
 
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This is a V8, and the noise seems to almost go away when I accelerate. However it is hard to tell when sitting in the drivers seat since this car is not quiet. Was tempted to get the wife to gently accelerate while the car was up on ramps but we just had a fight and I didn't feel like trusting my life to her at the time.
I know you have a V/8. I just mentioned the V/6 (3.8L & 3.9L) because exhaust leaks coming from the exhaust manifold area are almost a given on them (loose/broken exhaust manifold bolts or a cracked manifold). People who own HEMI RAM trucks will also recognize this noise. You don't need to gently accelerate to hear an exhaust leak. Just hit the gas when the car is in park/neutral (you don't need to rev the engine very high), an exhaust leak tick will become noticeably louder as the engine accelerates from idle and mostly go away when you release the gas, especially when it is cold.
If the knocking that you are hearing goes away when the engine warms-up it is likely piston slap. GM 6.0L V/8s are notorious for this.
 
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If it was mine I’d pull the valve covers and check all the rockers. If the phasers have never been done that is also a possibility but that pitch of noise isn’t correct for phaser noise IME
 

Barkleymut

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I pulled the valve covers 6 months ago and everything seemed ok (although I am an amateur at rocker/roller/cam inspection). Plus the noise was not nearly as noticeable when listening up top...it is definetly louder under the car.

The screwdriver to my ear test does not give me any concern when listening to the valve covers.

I am leaning towards piston slap or maybe worn chain guides. There is a youtube video discussing the seals that blow out frequently on the chain tensioners and cause a lot of problems with the chain guides.
 
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If it was mine I’d pull the valve covers and check all the rockers. If the phasers have never been done that is also a possibility but that pitch of noise isn’t correct for phaser noise IME
Oddly enough, my recent Camry top-end rebuild made the same noise (but much quieter) for the first 5-10 min of idling, then it went away. Not sure what happened, but it has been driven over 150 miles and all is well.

I would probably smoke test the exhaust and also remove the valve covers for inspection.
 
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I pulled the valve covers 6 months ago and everything seemed ok (although I am an amateur at rocker/roller/cam inspection). Plus the noise was not nearly as noticeable when listening up top...it is definetly louder under the car.

The screwdriver to my ear test does not give me any concern when listening to the valve covers.

I am leaning towards piston slap or maybe worn chain guides. There is a youtube video discussing the seals that blow out frequently on the chain tensioners and cause a lot of problems with the chain guides.

Timing drive noise would be most noticeable at the front of the engine.

Does the engine rattle on cold start up for a few to several seconds?
 

Barkleymut

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Does the engine rattle on cold start up for a few to several seconds?
A little, but the darn thing has some type of automatic throttle that gives it gas for 5-10 seconds so that the rpms stay at 2k upon initial start...so it is hard to hear exactly what is going on.
 
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