Help! New Engine Noise

Here is my 2 cents. If it makes that noise again I'd give the IAC a good smack with the handle of a screwdriver. If that doesn't change things. Unplug the IAC while it is running. See what happens.
And while I just told you to hit the IAC. I don't disagree with Kevin about NOT hitting things with a hammer and listening with a long screwdriver. The listening technique works and does help.
That does not sound like a bearing noise in any case from my point of view.
And someone else suggested the PCV. I have absolutely replaced PCV valves for customers that have made that noise.
 
supergordo said:
. Unplug the IAC while it is running. See what happens.
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Did that this morning. Unfortunately I wasn't filming. The engine died within two seconds or so. I think the rattle did  not stop immediately when I unplugged the IAC valve, which I guess would suggest that the IAC isn't the issue.

Nonetheless, I just replaced it with a junkyard unit courtesy of a '99 E-150 4.2; at least that way I can rule it out. Plus my stock IAC has been known to be on its last leg; a year ago, it kept me from starting the engine, but then worked again after a good cleaning.

The E-150 valve has some major corrosion of the housing, but at $12 it's worth a try. At least it's an OEM Ford part.

20250321_143210.jpg

supergordo said:
And someone else suggested the PCV. I have absolutely replaced PCV valves for customers that have made that noise.
Click to expand...

That was literally the first thing I replaced after buying the car three years ago. Granted, that was a cheap Autozone unit. And I didn't even know why I was replacing it; I just wanted to do something, and that was easy. I still have the stock PCV valve somewhere.
 
Three days in a row, I started the car early in the morning, in coldest possible conditions, and no noise was present. One could assume that the swapped IAC solved the issue, but I'm skeptical since unplugging it the last time the noise was present did not stop the noise instantly.

Meanwhile, it's been dry for days. Now it's raining. If it's an electrical arcing issue, humidity may be the deciding factor.
 
This particular noise hasn't occurred in weeks. It seemed cold/rain related, so I may come back to this thread next winter. For now, knock on wood, all is well.
 
1997ThunderbirdLXV6 said:
This particular noise hasn't occurred in weeks. It seemed cold/rain related, so I may come back to this thread next winter. For now, knock on wood, all is well.
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So, you think replacing the IAC with a used one may have fixed your issue?
 
1997ThunderbirdLXV6 said:
No, I don't believe that's what it was. But I really don't know.
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I hate when that happens. And it has happened to me a lot. The other day, I start the car and drive off... the car is running like I pulled two plug wires and stuck a stick in the spark plug hole... I had no idea WTF I did or what happened. I went into the store, got my stuff, came out, started the car and WAM! Drove like it was new. Go figure.
 
After working on my car and getting it running again, I have a tapping noise on the passenger side of the engine. I read it could be the valve tappets are lose or could just be the injectors rattling away as the open and close. I will use a stethoscope to listen where the noise is and go from there.

I had to laugh when I replaced the altenator on my Town Car cause it was making noise. After doing that, I found that the noise was coming from the valve body... :facepalm:
 
Using my stethoscope, I found the tapping noise to be coming from the injectors, not the valve body. I could hardly hear the valves doing their thing, but the injectors made it very clear they were the ones making the noise. It went away after a bit.

Problem solved.
 
White Lincoln said:
Using my stethoscope, I found the tapping noise to be coming from the injectors, not the valve body. I could hardly hear the valves doing their thing, but the injectors made it very clear they were the ones making the noise. It went away after a bit.

Problem solved.
Click to expand...
I'd run some Lucas injector cleaner in it for the next few tank-fulls of gas
 
1997ThunderbirdLXV6 said:
Got into my car. Opened windows. Started engine; startup was normal. I immediately noticed an unknown noise. Opened hood and recorded video below. What is this???
  • Appears to originate from top center/center right of engine.
  • Sounds like a very fast tick (?).
  • After recording, I shut the engine off; I did not check as of yet whether it changes with rpm, with shifting into gear, with A/C on, or whatever other condition one could come up with.
  • I gave it a tiny bit of throttle, but all I can say is that the sound persisted.

Click to expand...

Ok, bringing my original post back from the dead, because it's happening again. I didn't record a new video, but this older video in my original post still applies.

Opened the hood, and then I pulled the PCV valve up, but not all the way out, and it stopped. Pushed the PCV back down, and the noise started again. Even just pushing onto the PCV valve while fully seated seemed to alter the rhythm slightly.

What's interesting is that the noise suddenly cuts off. I'm guessing about two minutes after starting the cold engine, I hear a single click, sounds almost like a switch, and the noise cuts off entirely.

Any new guesses what this is?
 
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