Heater Gremlins
 

Rover 75 2.5 Auto Club 2001. The car has got air con. and climate control. I have a noise from the centre of the dash behind the heater controls. I will decsribe it best as I can !!! Its a soft whiring noise and a bit clicky but seams to only happen when the left hand heater control is set over 20 degrees ? The noise gets slower the higher you go but quicker as you go down the way. If I turn off the heater it still does it for a few mins. Its intermitant and not there all the time. To me its like maybe a sticking motor/motorised valve/flap/solenoid that sort of thing but a real pain as i can hear it working away. Again as I said only now and again. The olny way I can't hear it if I turn up the radio volume. I look forward for you comments on this one. Regards, Robin.

The whir and click you describe appears to be the vent opening and closing. AFAIK this should only occur when the the ignition is switched on to open and off to close, otherwise I'm sure it should remain static when in use.

Morning Robin and a welcome over here,

I had a clicking noise a few months ago when I had the left temp control set between 20 and about 24c. Noise seemed to come from behind the glove box.

Did all the tests (details on the other forum) but nothing showed up. Decided it was probably a sticking distribution valve and a flap was just flapping. Never did find the time to take things to pieces and the noise went away after about four weeks.

Suggestion: If its a clicking/flapping noise leave well alone for a week or so to see if it gets better or goes away. The previous owner of your car may not have used the A/c much.

On the other hand if its a whinnig noise I am a bit stumped. I have had two auto 75 V6's and both have (on and off) made a whinning sound seeming to be related to the revs of the engine and in lower gears and at lower speeds like in traffic. Noise seems to come from aroud the middle of the dash at just below radio level. But when you switch the A/c off the noise goes away !

With a bit of luck somebody will come along later with an explanation.

Regards

David

It could, as GG suggests, be the air recirulation motor.

Assuming the ATC is set to auto then the following should happen:

1. On ignition position 2 - the Air recirc. motor opens to the outside air flow.
2. On ignition off - the Air recirc. closes the outside air flow.
3. If the cabin temp. is quite a bit higher than the outside air temp then the ATC will CLOSE the outside air flow until a more suitable interior temperature is reached. This event can happen at anytime whilst the car is running if the temperature difference is high enough.

You can overide the Air Recirc. control via the appropiate button on the ATC pannel and this will cause the vent to close the outside air flow until you either switch the engine off or you press the air recir button again or the Auto button.

If your car is doing something other than above then something could be amis.

Thanks for that Simon and I think I understand what should happen.

I will play with the recirc button to see if that makes any difference to the noise.

But the bit I am not sure about is this. The recirc motor should work briefly to open or shut a flap ?? The motor would probably be single speed ??

If that is the case why would the whining noise similar to a worn gearbox (or a worn electric motor) rise as the engine revs decrease and fall when they increase.

Do you think it might have anything to do with the A/c fan (not cooling fan) which has I understand a fair number of speed settings when a/c is auto but only six when in manual??

The motor may be single-speed but the bits it moves are a set of linkages and bearings. It may be these that are making the noise rather than the motor itself.

If it is not the air recirc motor then something else is causing the noise. Have you gone through all of the manual settings for each vent combination to see if it is the same noise accross the board or if it is limited to a certain speed/temp/vent combination(s)?

Also, does it do it when your driving (ie engine running) or when sationary and when the engine is off?