Funny Noise(Whistle) Coming From Vents When Air Circulation Starts On

leksa250 · April 4, 2013

Hi guys!

I am getting funny noise(like a whistle) coming from front vents when air circulation starts on the cold engine .It is not the first time when it happened ,firstly I couldn't find where the noise was coming from ..then next morning (only when engine is cold)I started playing with the air con and ventilation system and I noticed that when I swtiched off the fan ,the whistle was gone as-well. If you leave the fan on ,the whislte noise will go away after 5-10 minutes engine running.Anyone had this problem before ?Any ideas what that could be?Many thanks in advance jack

ronnaybarkay · April 11, 2013

Not sure if it may help,but I understand there is a small servo inside each vent for controlling the direction of the airflow from each vent. I had Lexus Sheffield examine a knocking noise from the car and the identified the from shock absorber. In addition the technician picked up on the servo in the vent next to drivers door window always moving causing a noise. Lexus wanted £299 to fix. I went to my local garage where I bought the car and they said the could do it for less than £100. The only issues with some vents is the dash may need to come out. Its none essential so Ive not bothered.

It may be totally wrong as a suggestion.

rog99 · February 1, 2015

Hi jack

A slightly old thread but might still be getting some reads so i'll reply anyway.

My RX400h has a whistle when the aircon is in re-circ mode. I guess this is something to do with the path the ducting takes (maybe too many corners or too narrow or something).

When your engine is first started the aircon fan speed will be high to get to your preset interior temperate quick. Once it gets nearer to that then the fan speed slows down...and the whistle is no longer audible. You can test if this is the same whistle by going into the fan settings and manually altering the speed up/down with the re-circ mode on, and see if the whistle stops.

Now if anyone knows how to eliminate this whistle, other than setting the fan speed manually, i'd be pleased to hear about it.

(re-circ mode is preferable in queuing traffic etc rather than sucking in exhaust from other cars which selfishly don't automatically stop the engine and run in EV mode when queueing ).