Two Mystery Noises.

**Jason789** · 30th April 2011, 07:54 PM

Hello,

I have two noises coming from my TD5.

1) Sounds like some sort of electric motor from the passenger side foot well each time I'm coming to a stop at traffic lights etc.
2) Sounds like stuffed bearings of some sort slowly spinning somewhere in the dash behind the radio when I'm waiting for the glow plugs to heat when starting the car.

The fan for demisting etc is working, has been removed and cleaned.

I have no idea of these noises. Is there reason to be concerned??
Any feedback or theories would be appreciated.

Cheers,

Jason

Sully · 1st May 2011, 12:34 AM

Noise one is your climate control vents moving about. This is more noticeable when the cc is turned off, or when not on auto.

No real cause for alarm.

Noise Two.... No idea.

**mturri** · 1st May 2011, 07:18 AM

1) Servo motor that controls air inlet source by closing/opening a flap within the air distribution box; per RAVE:

"The inlet air source is automatically controlled whether the air temperature control (ATC) is on or off. While the system is on, the inlet air source
can also be manually controlled to give timed recirculated air or latched recirculated air.

While the system is off, the ATC ECU uses vehicle speed to determine the inlet air source. With the vehicle at rest, the inlet air source is set to recirculated air. When vehicle speed reaches 17.5 mph (28 km/h), the inlet air source changes to fresh air. The inlet air source then remains at fresh air until the vehicle speed decreases to 5 mph (8 km/h), when it returns to recirculated air.

While the system is on, the ATC ECU uses the LH and RH temperature selections, vehicle speed, ambient air temperature and coolant temperature to determine the inlet air source. In the automatic mode:
- If one temperature selection is set to LO and one is set to a specific temperature or HI, the inlet air is set to recirculated air.
- If one temperature selection is set to HI and one is set to a specific temperature or HI, the inlet air is set to fresh air.
- When specific LH and RH temperature selections are set, the inlet air source remains at fresh air except when the air distribution function is set to face level only or face level and footwell outlets. If the air distribution function is set to face level only or face level and footwell outlets, at 56 mph (90 km/h) the inlet air source changes to recirculated air (to exclude ram effect, which becomes excessive at speed). When the vehicle speed decreases to 37.5 mph (60 km/h), the inlet air source returns to fresh air."

2) Possibly the in-car temperature sensor blower, see this post: http://www.aulro.com/afvb/discovery-...ng-column.html

**Fluids** · 1st May 2011, 10:06 AM

1) could also possibly be the ABS motor ... on the basis it only happens when coming to a stop each time. Does the brake pedal pulse/vibrate when it happens ?

2) mturri is spot on. Time for a cleaning. Follow the link.

**Jason789** · 1st May 2011, 11:07 PM

Hello,

Thanks for the info on the climate control. I didn't know that the climate control switched from fresh to recirculated air depending on vehicle speed. This probably explains both noises that I am hearing(its harder to focus on the noise heard while slowing down due to watching traffic etc). I had no idea that they could make a car climate control do such things automatically
I'm fairly certain that its not the temperature sensor blower in that the noise is not coming from that area(although a project for the future).

Thanks for the replies.

Cheers,

Jason

Thread: Two Mystery Noises.

Thread Tools

Two Mystery Noises.

Bookmarks

Bookmarks

Posting Permissions