My wife complains of a noise that I have only been able hear once. It happened on acceleration and was a low-level hum of about 2 seconds duration. I immediately decelerated and it repeated on the downswing. My wife says she hears it more frequently lately and it seems to occur after the car is switched off and it sits for 20 or 30 minutes. We have taken it to the dealer several times but, of course, it never happens when they have it. Has anyone experienced such an event with their car?

 

(06 STS4) I don't have a noise that comes and goes, but there's a constant noise on acceleration that's driving me nuts. Its a wherr sound, like the alternator is going bad. It can only be heard inside with doors and windows closed. The dealer says it's a pump yadayada dealing with the AWD and that it's normal.

 

Thanks for the response, rudyeons. Update on my problem: Last night, I was driving the car. Due to road construction, I was traveling about 45 mph. I heard the noise and it was constant on acceleration and would disappear on deceleration. While I was slowly accelerating, a pushed the transmission selector to Neutral while maintaining acceleration and the noise disappeared. Reengaged the transmission and the sound immediately resumed. Did this several times with the samr results. I am now of the opinion that it is transmission related. I have yet to contact the dealer but intend to shortly.

 

if the problem is the same one i had and i will bet it is, its the manifold. I had problems with mine since about 23,000 miles they finally got it fixed right before my warranty ran out. Mine had a grinding noise on acceleration sounded like from the steering column but in fact was the manifold leaking. hope this helps, by the way when they fix it your car will smell like rotten eggs for a few days. 05, sts nothing but problems. lawsuit winner.

 

Thanks, Jeff. I still have not nailed down the noise so I'll certainly check out the manifold. Sounds very possible. Have a great day. Wm..