jkurz

Yes, it is so loud that it is difficult to tell where it is coming from. I had somebody else ride with me. they seemed to think that the vibration/noise was actually coming from the transmission tunnel although it can be heard throughout the car...

I was getting this sound too, after I found that my antifreeze level was really low I’ve added more and it went a way. Check the level of your antifreeze. Hmm, interesting. Thanks for the option, I never would have though of that, I will have to check it out and let you all know if it works! Did you ever solve this issue? My 2000 GS300 has been making the same noise.

I have what I believe is a similar noise. Has yours been diagnosed. Mine almost sounds as if it is in the air conditioner vents.... almost sounds like

I have a 2000 GS300 with around 85000 miles on it. This year we have had some extremely cold mornings in NC. When the weather is below freezing (in the 20's) the car makes a whistling/humm which is very noticeable in the passenger compartment. The noise only occurs between around 33 - 37 MPH and gets gradually less noticeable as the car warms and eventually disappears after 20-30 minutes. Also, if the car is kept warm in the garage the noise does not occur. The noise seems to be coming from the area of the transmission tunnel just behind the front seats although it is difficult to tell where exactly it is coming from. If I put the car in nuetral and coast the noise remains. If I turn the engine off and coast, the noise remains... and always seems to be in the 33- 37 MPH range. Could it be the rear engine mount (transmission mount)? Does anyone have any ideas?