High Speed High Frequency Noise

[engine23ccvfd]

Hello All,

When travelling at 80MPH and above do you hear a very high frequency noise. I am wondering if it could be caused by the valve stems or something on the front air dam could be the culprit.

[Dr Caleb]

When you look in your rear view, are there red and blue lights behind you?

Seriously, I've never heard anything. Where is the noise coming from? All around, front? back?

Turn everything off - radio, fan etc to narrow it down. It could be anything, it's kinda tough to disgnose something like this with a keyboard :)

[engine23ccvfd]

I cant figure out where the noise is coming from since its such a high frequency and I am partial deaf in my left year. It is not related to the AC (since it sucks I usually use the window down method), I doubt it is the fan since I dont hear the noise in the same RPM range at slower speeds, it does get louder if I am close to a divider wall on the freeway (just bouncing more sound waves back my way), and its not electrical noise.

[gonzo50]

Originally posted by engine23ccvfd
Hello All,

When travelling at 80MPH and above do you hear a very high frequency noise.
I really never paid it to much attention, mine does it too. :confused:
It almost sounds like the gears in the transmission meshing together like in a supercharger, or the torque converter, coming from that area.
All is fine here, just that high pitch whine at speeds. Anyone else ?

[TripleTransAm]

Tire noise? I have noticed these tires emit a specific kind of sound, one that I don't experience in my other cars with non BFG tires.

[Dr Caleb]

Originally posted by TripleTransAm
Tire noise? I have noticed these tires emit a specific kind of sound, one that I don't experience in my other cars with non BFG tires.

That would make sense. I've had BFG T/A's that made kind of a 'slapping' sound at low speed, which became a high pitched whining at high speed. A change in tire pressure (2-5 pounds UP) made a difference.

I haven't noticed this in the MM though. But I don't drive anywhere that i can hear the sound of the car reflected back at me, such as a tunnel or overpass with solid divider.

[gonzo50]

Originally posted by TripleTransAm
Tire noise?
I thought it could be something simple like what you said, because all of my prognosis is "AOK". :coolman:

[Agent M79]

I don’t have one yet but I was privileged enough to drive one recently. I noted a high pitch whine in or under the center stack. I was informed it was the hydraulic pumps in the transmission.

After hearing that I pretty much dismissed it so I don’t recall if it made the noise constantly at cruising speed or just when shifts were necessary.

[TripleTransAm]

The transmission thing sounds like a plausible reason. I've noticed that Ford auto transmissions since the early 80s were always noisier than others (maybe it's an overdrive-tranny-specific thing?). I find my MM's tranny is much quieter than those 80s whiners, but I gotta add that under WOT on the track, it does shriek up a storm!

[RCSignals]

engine23ccvfd and Gonzo50. I guess it's your wheel locks, since that's what you both have in common on your cars and are both experiencing this same phenomenon ;)

[TripleTransAm]

LOL! Actually, I was going to suggest it was something to do with those damned noisy 300As... :)

(on a quiet night, if you listen carefully, you can hear the sound of your wiring harnesses being sliced through... that, and Fourth Horseman's noisy rear suspension...)

[engine23ccvfd]

Hmmm wheel locks could be. I think I will put the factory lugs back on for a day or two.

I really dont think its the tranny the noise doesnt get any louder at a 100MPH than it does at 80 but it does have a higher pitch....maybe if I go fast enough it will raise above 22,000khz and I wont be able to hear it anymore :)

[MAD-3R]

Normaly that High piched noise comes from the passanger seat... ok, the pasanger.

[engine23ccvfd]

Normaly that High piched noise comes from the passanger seat... ok, the pasanger

Holy crap I am not even going to touch that one!!!! :flamer: :flamer:

[Petrograde]

I get the high pitched whine at 80mph too. It sounds like it's coming from the driver's window weather stripping to me. I dont have wheel locks so I know it's not that.

[RCSignals]

These cars have a double door seal. I don't think it's air entry. Perhaps at those speeds you're hearing wind nose as air flows over/around the mirror?

[Jeff]

I haven't noticed a high-pitched whine...oh, maybe if I turned down the stereo! :lol:

[GarageMahal]

I have heard a whine at freeway speed too, but only when it is wet out. I am sure what I hear is from the tires.

jta

[TAF]

deer whistle? :confused: :lol:

[TripleTransAm]

Well, I gave it a shot this afternoon. I couldn't make out any whine that was really noticeable... if I concentrated really hard, I could make out a slight hiss from the passenger's side of the dash.

I'm going to agree with RC's take on this and proclaim it wind noise (at least, on my car). I'm thinking it's the wind rushing past the wipers or perhaps the mirror or maybe even the windshield trim, and it's all being amplified/resonated within the ducting of the climate control system (which is why I'm hearing it from the passenger's side of the dash).

I have to specify that this 80 mph cruise was performed on smooth blacktop... if any of you are on cement, then it may be a different story. It's very possible that the tires hiss louder on cement than on blacktop.

Trivia: supposedly (as told to me by a civil engineer acquaintance), road noise from driving on cement is similar (volume-wise) to road noise on blacktop. The reason cement seems so much louder is that the noise generated is at a higher frequency that humans notice much more. Hence we perceive driving on cement highways as 'noisier'.

[TAF]

I had BAD wind-noise that was finally located on the drivers-side, rear door, fixed-glass. I had the whole fixed glass unit replaced. I must say that at speeds from 80MPH up...there is a LOT of windnoise from the sideview mirrors. Poor design? Or...just slow down?

[TripleTransAm]

Air brakes... ;)

Funny you mention the fixed glass noise. You reminded me of something I noticed within 5 minutes of leaving the dealership with my brand new Marauder, last March. Lots of wind noise from the passenger's side rear, from the fixed glass area. I made a mental note to the effect of keeping an eye on it in case it got worse... it was pretty loud as it was.

What's funny is that it no longer appears to be happening. I *doubt* I simply got used to it, especially since I tried so hard to pick off any extraneous noise this afternoon during my 80 mph test cruise. I can't explain it.

My last full-size RWD experience was the '85 Parisienne, and the air rushing over the vinyl roof made a heck of a whoosh. I never did get used to it, hence I'd be surprised about tuning out the fixed glass noise mentioned above.

[TAF]

3TA,

We isolated it by taping around all the windows... I put my tech in the back seat, and we drove around for an hour at different speeds stopping and removing the tape. He was VERY patient...and we found it and fixed it.

Did I tell you that we in ATL have the BEST tech in the world working on our Marauders? He's done I think 8 so far and I'm introducing another board member this week. Thanks again Dennis for the referral!

[Bigdogjim]

Sound does travel in a car so it can be very very hard to pin point the area. I would look under the front end for a "loose" air dam/fitting?

[TripleTransAm]

A heat gun was used during the tinting process... perhaps this had something to do with my disappearing wind noise? (although I'm still fairly certain it was already gone by the time I got the car tinted).

Nonetheless, good on you for taking the time to fix this. I certainly would not have put up with it for any considerable length of time.

[Petrograde]

Now that you mention it, ... The noise did get quieter after I tinted the windows.