Whistling at startup?

[J Piroth]

Every time my ST has been sitting for a while, there's an odd whistling noise when I first start it up that seems to be coming from somewhere in the engine.



It's kind of a hollow, constant whistle/whine that goes on for a few moments. Then, the RPMs settle down and the noise goes away. If I don't wait long enough for it to quit on its own, the RPMs drop and the noise goes away as soon as I put it in gear.



Could this be a precursor to the dreaded cracked elbow, or something else? I haven't thrown a code, and there doesn't seem to be any effect on performance.



Thoughts?

 

[Thomas Rogers]

Piro,



Do you park outside at night? Is it really cold where you are (well below freezing)?



If so, it could be the alternator. Some 1st gen STs had a condition wherein the alternator would whine when very cold. It would sound louder as the RPMs were increased, until the engine warmed up.



I had this happen when the temp would fall below 15 deg F.



TJR

 

[J Piroth]

TJR,



I do park outside, but I'm in Florida, so the coldest it got last night was in the 40s and it did it this morning.



It seems like it may last a little longer when it's been cold/cool out, which was one reason I thought it might be a hose or something else that needs to warm up and relax before the engine settles in at its usual idle RPMs.

 

[Thomas Rogers]

Piro,



Then it's probablu not the "extreme cold" alternator issue, not exactly anyway.



But it could be related. The next time it happens, grab a friend, have them accellerate and you listen with the hood popped to see if the noise is coming from the alternator.



Tom

 

[Tom Schindler]

Without hearing it, I can't tell you for sure, but it could be the ISC valve. My brothers did that.



Is it really loud and annoying?





Tom

 

[J Piroth]

Tom,



It's not loud, but definitely noticeable. Happens every morning, or other times when the ST sits for long periods of time, and it seems more pronounced and like it goes on longer if it's been cold/cool out.



As it whistles, the RPMs sit around 1500, then they drop down to 1000 or so and the whistling stops.