High pitched buzzing at Highway Speed

[mikebnissanz]

I've recently had my car recovered from a theft and a lot subsequent repairs (luckily mostly covered by insurance). Among the repairs was a clutch and flywheel replacement, and oil pan resurfacing. Since I've gotten the car back, I've noticed that at highway speeds there is a faintly audible high pitched buzzing (sounds like it could be metal on metal, or maybe like a very quite high pitch spinning saw) coming from the front end of the car. It's not audible with the top down or the radio on, but is noticeable otherwise. The pitch of the buzzing noise doesn't change with rpms, and the noise doesn't seem to occur at all at lower speeds. My dad (the previous owner of the car, who unfortunately doesn't live nearby) said a similar noise in the past was a result of a speedometer wire in need of replacement.

In the next couple of days I can post a audio file of the noise (as best as I can capture), but I figured I'd check if anybody has run into a similar issue or can suggest any questions. Also suggestions for good SF Bay area repair shops to help me investigate would be very much appreciated. Thanks for your help!

--Mike

[evildky]

Welcome to Nico! The fact that the noise occurs only at high speed would suggest it's something coming loose and vibrating in the wind like a splash shield or fender liner or even the fan shroud making contact with the fan blades. I'd gut the car up in the air and start poking around. I have to ask, what int he works are you calling "oil pan resurfacing"? Did you have to have a hole fixed?

[mikebnissanz]

Thanks! "Oil pan resurfacing" probably = me being hosed a little bit by a mechanic. They said the pan was super corroded and basically likely to start leaking oil very soon

[DCaff300ZX]

Another possibility since you said you don't hear the noise with windows open, it may be the fan in the upper console that circulates air around for the climate control. Just a thought since you have little to go on...

[DCaff300ZX]

Oh, just hit me- after some brake work I had that saw-like sound exactly myself once and it was the shroud plate on the backside of the brake rotor making minute contact with the rotor when moving. It would make a little noise nearly inaudible getting going, but become the saw-like sound you mentioned at higher speeds.
I'd just done brake work is the only way I found it...hope this helps!

[evildky]

So basically the sanded off the rust and hit it with a rattle can, not a bad idea if it's rusty, the question is why is the oil pan rusty? this a "low miles JDM engine that came on a pallet and was shipped and scooted on it's oil panto make a bare spot for rust to start? Or did someone bottom out the car on a curb or culvert?

[mikebnissanz]

Almost certainly the latter, many times It is quite low miles but lived on the east coast for awhile and was driven by my not so careful brother.