I have an S40 1.9D and notice of late that there is a rattle/tin sound when I put on the heater. This seems to last until the car warms up and is very irritating. Anyone got any ideas on the cause?

have you tried putting the blower from off to full speed a few times? maybe there's something in there. Fixing this kind of stuff (deep in the dash) is not easy. :(

There might be a leaf stuck in the blower motor.Have you changed the pollen filter lately?

Thank you for the reply. The noise only occurs when the temperature dial is turn to hot - it never occurs at the cold setting even when the blower is turned on. Would changing the pollen filter help?

It might help some. There might be something in there still and when it is on hot the air moves diffrently through the heater box assy.

Thanks again. Can you tell me where the pollen filter is and is it easy to replace it?

Remove the under dash panel on the passenger side.In about the center you should see a cover.You will have to push in on the tab and drop the cover and the pollen filter is in there.

Once again, many thanks. I'll let you know how it works out.

No problem anytime.

I changed the pollen filter and it made a small difference to the noise. The good news is that I discovered, through trial and error, that the noise level is dependant on where the direction of the air flow is set. Thus when it is set to the 12 o'clock position i.e. pointing to the windscreen, there is no noise - however turn the dial to the 1 o'clock position and the noise starts. As this is the only position that I can hear the nosie, I am quite happy to avoid this setting. However, the noise does disappear when the engine heats up.

There might be something trapped in the vent system.