4.0L SOHC High Pitched Whistling Noise

[Rhett]

Maybe it was the DPFE solenoid

Yes, in addition to what I said above, the solenoid also made a high-pitched noise. That was a bad one. Not just the valve and tube. It got so loud you could hear it down the street.

 

[LoquetusofBorg]

Does this whine go away under a load? or does it stay the same?

 

[LoquetusofBorg]

If you can here whether or not the whine is still the same under a load then you are most likely looking for a vacuum leak, try a smoke test.
Loquetus

 

[LoquetusofBorg]

By smoke test I mean smoke the outside of the vacuum lines and see if it gets sucked in and if that does not work put smoke to the inside of the vacuum lies. That test will rule out any of your lines.
Loquetus

 

[koda2000]

Does this whine go away under a load? or does it stay the same?

No, seems to remain constant and again it's not a whine, it's more of a whistle. I'm not going to have time to fool with it this week (too much going on) but I'll get back to it when I have the time.

 

[LoquetusofBorg]

Well I am super curious now and I most likely won't let this go as noises like that bug the hell out of me too. The whistling is constant then it will be vacuum related as that is the only constant regardless of load.
Loquetus

 

[CDW6212R]

Take the engine cover off and see if the sound becomes louder. That cover slightly muffles sounds from the DPFE which is under it.

 

[koda2000]

Take the engine cover off and see if the sound becomes louder. That cover slightly muffles sounds from the DPFE which is under it.

On the Job 2 engine the cover doesn't cover the DPFE.

 

[CDW6212R]

Okay, I forgot how small those are.

 

[LoquetusofBorg]

Wish I could be there to help you disconnect one vacuum line at a time to find that annoying whistle, could be fun. You could set up a webcam and I could be there in spirit watching you while having a sandwich, hahaha. Just having a little fun with ya Koda, good luck as I know it will go quick for you.
Loquetus

 

[RandomNerd2000]

I pity whoever got a red negative battery cable, that looks incredibly stupid.

 

[koda2000]

I pity whoever got a red negative battery cable, that looks incredibly stupid.

LOL, yeah the previous owner was a real dope. You should have seen some of the weird stuff I found done to this poor truck. At least the red ground cable is functional.

 

[RandomNerd2000]

Yeah, but at least here they sell both, same shelf, side by side so I mean, that just adds insult to injury on his part.

 

[koda2000]

Yeah, but at least here they sell both, same shelf, side by side so I mean, that just adds insult to injury on his part.

I would have been happy if the battery cable was the only dumb thing he did.

No A/C - broken A/C high pressure switch from changing the #4 spark plug (one of the 5 plugs and plug wires he managed to change). I'd wondered why there was one brand new plug and plug wire in the bed.

Had no heat - vacuum hose off the heater control valve and a dead blend door actuator.

He removed 3 interior door panels, lost a bunch of pieces/hardware and broke EVERYTHING (and I mean literally every single thing) inside the driver's side rear door, because he came to the conclusion that 3 window motors all died at the same exact moment... problem was a bad master window switch.

Ran the rear diff empty because he didn't replace the leaking axle seals, got water in it and ruined the ring and pinion gears, spiders and even the axles shafts.

Apparently never changed the engine oil or trans fluid and filters in the 180k he owned it.

The list went on and on. Would it make you feel better if I put some black shrink wrap on the red ground wire?

 

[CDW6212R]

I saw the red cable too, and it always bugs me also, but I remember well that 25+ years ago you could only buy red cables of various lengths. If you wanted better, or black, you had to go to the dealer, or have it custom made.

 

[RandomNerd2000]

Nah I personally don't care that much, I just can't get over his level of ignorance.

 

[AnnoyedUser]

This very annoying high-pitched squealing sound definitely seems electronic in nature. On my 2007 Sport Trac, it occurs ONLY WHEN:

1). It is a hot day (85 F or higher); and,
2). The car is running at 65 MPH or higher; and,
3). The car has been running for at least 10 minutes.

This awful noise occurs regardless the radio being on or off.

I VERY HIGHLY SUSPECT it is a malfunction with the TPMS (Tire Pressure Monitoring System), which sends RADIO signals to the vehicle's computer about tire pressure AND temperature. As soon as I slow down to under 50 MPH, it stops.

Can't believe Ford doesn't definitively know about this? What is the solution? Thanks for whatever suggestions occur.

 

[donalds]

The only thing I can think of
Just throwing it out there
Ignition coil
A bad capacitor on the ignition coil

Does it sound like a dog whistle

 

[AnnoyedUser]

The only thing I can think of
Just throwing it out there
Ignition coil
A bad capacitor on the ignition coil

Does it sound like a dog whistle

Not a whistle, exactly. More like a very high-pitched humming noise. Sometimes intermittent, sometimes constant. But most importantly, it occurs only when all three conditions above are present (ie, hot day, high speed, & vehicle has been running for at least 10 minutes).

 

[donalds]

Still sounds electric in nature