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infinitenexus
infinitenexus HalfDork
11/24/20 1:09 p.m.

2012 mustang gt, always well maintained, suddenly developed a very loud knock.  Only 69k miles.  It ticked lightly for a bit (I rarely drive the car) then suddenly boom, this sound 

https://youtu.be/zUpz-rdMwgg

 

big yikes. I turned it back on to move it out of the driveway just for a second and when I gave it a little gas it sounded like gravel in my motor. 

Appleseed
Appleseed MegaDork
11/24/20 1:27 p.m.

I've had 2 22REs nuke their rods in my 4Runner. It's a sound I never want to hear again. 

Start looking for a GT500 lump to swap in?

infinitenexus
infinitenexus HalfDork
11/24/20 1:39 p.m.
Appleseed said:

I've had 2 22REs nuke their rods in my 4Runner. It's a sound I never want to hear again. 

Start looking for a GT500 lump to swap in?

Sadly no. I'm actually getting ready to trade this car in on something more economical, so this was a super annoying time for this to happen. I'll basically be dropping a bunch of money to fix it and then trade it in right after. 

jfryjfry (FS)
jfryjfry (FS) Dork
11/24/20 2:33 p.m.

started to ask how much as it sits, but i don't need it i don't need it i don't need it i don't need it....

...

how much as it sits?

clutchsmoke
clutchsmoke UltraDork
11/24/20 2:34 p.m.

In reply to infinitenexus :

2020 strikes again! Can you drop the oil pan, throw in some fresh bearings and send it?

z31maniac
z31maniac MegaDork
11/24/20 3:05 p.m.

Ouch. Thankfully I noticed it on my 135 before it got that bad, so I was able to trade it in.

jimbbski
jimbbski SuperDork
11/24/20 3:47 p.m.

I've had an engine with a rod knock and that sounds more like valve train to me. A rod knock had more of a ringing tone to it but what do I know.

I've never worked on a Ford DOHC 5.0L V8.

Subscriber-unavailabile
Subscriber-unavailabile HalfDork
11/24/20 3:50 p.m.

No bueno . When I had a 240sx I was driving down highway and when a car pulled up next I heard knocking, said to myself that car bout to blow, then my oil light came on and boom. Gl buddy!

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) UltimaDork
11/24/20 3:51 p.m.

In reply to clutchsmoke :

This is brotella, lucas and trade in

Professor_Brap (Forum Supporter)
Professor_Brap (Forum Supporter) UltraDork
11/24/20 4:50 p.m.
captdownshift (Forum Supporter) said:

In reply to clutchsmoke :

This is brotella, lucas and trade in

Facts. 

Streetwiseguy
Streetwiseguy MegaDork
11/24/20 5:20 p.m.

That's not a good noise.  It's either spun a rod, or ingested something that is stuck in the piston, because that is the sound of a piston hitting a cylinder head, I'd say.

Or the flywheel is cracked.

iceracer
iceracer MegaDork
11/24/20 5:26 p.m.

If it is an auto it could be a cracked drive plate.

Doesn't sound like any rod knock I've heard 

Shaun
Shaun Dork
11/24/20 6:39 p.m.
iceracer said:

If it is an auto it could be a cracked drive plate.

Doesn't sound like any rod knock I've heard 

I agree-  I've heard 'rod knock' quite a few times and it never sounded like that.  Maybe rod knock is in there,  somewhere..

dean1484
dean1484 MegaDork
11/24/20 7:22 p.m.

I would agree that does not sound like rod knock. Valve train is my bet. I would get a long screwdriver or better yet a mechanics stethoscope and see where it is coming from. 

dean1484
dean1484 MegaDork
11/24/20 7:24 p.m.

I would also pull plugs and see if I find any damage. Depending on what I hear/find I would then pull valve covers.

infinitenexus
infinitenexus HalfDork
11/24/20 7:47 p.m.
clutchsmoke said:

In reply to infinitenexus :

2020 strikes again! Can you drop the oil pan, throw in some fresh bearings and send it?

That's the goal. I'm hoping we can fix it that way and be done with it 

infinitenexus
infinitenexus HalfDork
11/24/20 7:50 p.m.

Thank you all for the replies. I'll try to look into it being valvetrain noise. The sound is very loud and sounds like it's coming from the front drivers side of the engine. Here's the fishy thing - my battery was also drained. That's why I was initially wondering if my alternator was just bad, but this sounds much too severe for that. 

Streetwiseguy
Streetwiseguy MegaDork
11/24/20 7:51 p.m.

In reply to infinitenexus :

Remove the belt and fire it up.

rslifkin
rslifkin UltraDork
11/25/20 8:35 a.m.

Last time I heard an engine make a noise like that (which echoed through the whole engine, making it hard to find), it turned out to be a totally collapsed / failed lifter.  Wasn't an overhead cam engine though, so I don't know if the valvetrain on this would make quite the same level of noise. 

nocones
nocones UltraDork
11/25/20 8:47 a.m.

What's the pulley ratio on for accessory drives?  I counted about 35-40 hits during your 11 second video.  If we assume 40 during 10 seconds that's 240/min.  Rod Nock would likely be 1-2* per rev (I'd think) as the piston changes direction.  If I'm off by my count you could be in the 1/4 of RPM range that would be valve train.  Are they interference engines?  What's idle speed?  It could be 1/2 idle speed and is just a cracked exhaust manifold.  Is the AC on in your video?  AC compressor or clufch failure could sound really loud and would be at some strange multiple of engine speed.

Sucks not matter what it is though.  You don't expect a low mile car to need this kind of attention.

noddaz
noddaz UltraDork
11/25/20 10:05 a.m.

Pull the drive belt and recheck.  Noise still there?  Disable one cylinder at a time to find out which cylinder.  Noise still there?  Look for a cracked exhaust manifold.  (It didn't sound like a rod knock to me either.)

TGMF
TGMF HalfDork
11/25/20 10:07 a.m.

Thought the 5.0's were supposed to be solid engines?  

z31maniac
z31maniac MegaDork
11/25/20 10:34 a.m.
TGMF said:

Thought the 5.0's were supposed to be solid engines?  

They are. But the reality is, sometimes E36 M3 fails.

pjbgravely
pjbgravely HalfDork
11/25/20 11:06 a.m.

It has been so long since I heard a rod knock that I can't remember parts of the test. When you shift it will get better or worse or maybe both. If it is steady during a shift it will be a main bearing or something else. It doesn't sound like a rod/main knock or a wrist pin to me.

bentwrench
bentwrench SuperDork
11/25/20 11:11 a.m.

Broken/loose flex plate?

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