Another engine noise post, sorry guys

[kountrykeith]

So I have a knock of some kind. Oil pressure good. It follows RPM. It sat for 6 years before me. Replaced fuel pump, cleaned tank rotten gas. Tried using regular stethoscope, didn't help. Any thoughts or experience helpful. Thank you.

Link to video
https://youtube.com/shorts/Z0620DvM9Lw

 

[Ramon Triton]

had a car with that sound before, i think it was valve lifters and was remedied by using thicker oil.

wasn't a ford though and i am no mechanic.

 

[JamaicaJoe]

Could be an exhaust manifold leak?

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[Yupster Dog]

I also think exhaust manifold leak. get under truck and look where the manifold meets the engine block. (sounds like the passenger side) you will see where exhaust has been leaking.(darker dust spot around the hole) usually it is the bottom rear corner that pops open first so it is easy to see.

 

[JamaicaJoe]

Could be a new leak caused when your cats were stolen.

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[kountrykeith]

Could be an exhaust manifold leak?

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Man I hope so. I heard a guy on here say something about putting a vacuum cleaner hose in the tail pipe, making sure its sealed then turn it on and you'll hear it whistle at the leak. Ever try that?

 

[Trainmaster]

I heard a guy on here say something about putting a vacuum cleaner hose in the tail pipe, making sure its sealed then turn it on and you'll hear it whistle at the leak. Ever try that?

Damn, sounds like a great idea. I want to try it now on my noisy Explorer and it's 18 degrees outside.

 

[JamaicaJoe]

Man I hope so. I heard a guy on here say something about putting a vacuum cleaner hose in the tail pipe, making sure its sealed then turn it on and you'll hear it whistle at the leak. Ever try that?

I expect you might have to close off the intake at the throttle body to perfectly seal off the engine. Be careful, unburned fuel getting into your shop vacuum might make for a "surprise".

I used to put a cloth over the exhaust of the running engine and stall it. If no stall, there was an exhaust leak,,,,somewhere.

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[jim8043]

I currently have the same kind of knock in my 98. sounded like it came from the rockers. followed a ford mechanics advice and checked for loose or blown out spark plug. Not it. took off the valve covers and replaced the lifters/lash adjusters. not it either. He suggested isolating the alternator and other things driven by belt. I removed the belt, ran it for a few seconds. Not it.

I am at a point where I have spent so much time not finding it that I am beginning to think it is in the lower engine. Perhaps a rod bearing or something. Although it is consistent, changes with engine speed even when speeding up or slowing down or under load or no load. Does at times seem louder, but not really sure. Temperature does not seem to effect it.

The exhaust manifold gives me some hope. I will try the vacuum cleaner or plug it to see if I can hear or see any dark areas around the manifold.

 

[Bilsto]

I don't know if this will help, but I've heard that the 4.6L motors are known for the timing chain guides to wear out and cause the chain to slap a little. Mine does it. Mine also has a bit of a knock that it does sometimes with a cold engine. Sometimes it doesn't do it though. It's weird. With 249,000 on it, there's a lot of noises that don't surprise me!

 

[Craig Lasnier]

I agree, exhaust manifold leak. Been there done that, that is also a known issue on these.

 

[Bilsto]

I agree, exhaust manifold leak. Been there done that, that is also a known issue on these.

I haven't heard if the 4.6 engines in the trucks do that as much, but it's pretty common in Crown Vics. I heard that they used inferior bolts to mount the exhaust manifolds, and that the tops of them just rust and pop off.

 

[lonestarjeff]

That sounds like chain dragging on plastic to me. Timing chain tensioner is my guess, but rule out the exhaust leak first.

 

[Craig Lasnier]

I haven't heard if the 4.6 engines in the trucks do that as much, but it's pretty common in Crown Vics. I heard that they used inferior bolts to mount the exhaust manifolds, and that the tops of them just rust and pop off.

I think your correct, the 5.4 had issues.