Smell in Aircon

my translated MR2 manual states that the air con should be used at least once a month to keep the compressor good or something, i like the eco setting on mine, works well and just turns the air con on and off to keep the temp constant, couldn't live without climate control now :)

It's not going into the motor. The motor is outside the housing.

Are you sure? Cos, thats crap. One of the best points of aircon, is that it demists the windows seriously fast.

All aircon's shut off at 5c and below, somthing to do with freezing.

The aircon button still works on most cars below 5c but the compressor doesnt kick in, have a look in your manual I know mine tells me this.

The compressor on mine definately does kick it, cos it makes a noise, i can hear it, and at idle the revs go up a smidge, no matter how cold it is. And there is no mention of it not working under 5c in my manual. Peugeot aircon must just be better than Audi :)

Volvos run the fan for 20 minutes one hour after you switch the engine off just for that reason!

as is my toyota :)

Common sense at last! This is very true. Think about what aircon does and its no surprise that they can stink. Bacteria love two things oxygen and water - some warmth also helps. Run the air con, water will as mentiond condensate on the evaporator. With all the air being forced through it you have totally ideal conditions for this stuff to grow.

There is of course on other funny way around this. Put a UV lamp shining on the evaporater this would kill the bacteria haha :)

Ed

Some shut off lower than that - 2 or 3 degrees.

Yeah but when it demists your windows fast you also end up misting it back up again as soon as you turn the aircon off.

Hmm, that sounds like a good idea...

This is to stop the thingamy from icing up. More or less by definition there is a de-ice sensor which stops the A/C once the lowest temperature bit reaches some value. 5c is rather conservative for this as it would imply a temp rise(loss) of 5 between the finned bit and the car interior. This seems to be a typically conservative design, by the way.

HST it doesn't seem to be all that likely that the car interior is sub 5c most of the time and once the car has warmed up a little you can still run the A/C to keep the lubricant circulating - which is a must even in winter as else the seals dry out and seize.

FYI, mine has a (aftermarket) rotary control in that I can wind up or down, to adjust the de-ice setting. The practical effect of this is the vent temperatures drop and the A/C works much faster, when dialled lower than standard. On a hot summer day - when this is most useful - the thingamy is highly unlikely to manage to form ice and even if it does, the ice forms on the outside and it just stops working temporarily, rather than causing damage. The principle is dead simple, just add a variable resistor in series with the de-ice sensor, could have it on a two way switch, resistor or direct, like a "summer / winter" thing. As to what resistance to use, I've no idea.

Only the ECC ones, and only after a certain model age (probably around the V70 new shape, S80, S60 type models. I don't think the previous generations did, though.

Air-con compressors / systems tend to have thermal cutouts - at both extremes. In cars I've had with air-con / climate control, the lower cutout has varied - in some cars 0c, others 2c. Although 5 sounds a little on the high side, I'm fairly sure I've heard of 4, so it could be on the money.

And you know why? Because the moisture that's built up on the evaporator and other parts of the ducting is being blown through to the cabin.

Well, it worked all through the winter, including those -5 days we had :)

Possibly the under bonnet temperature was allowable, also could be a fault with the temperature sensor - or simply a bigger leeway in lower temperature than most.

But I assure you car air-con systems will almost certainly have thermal cut-off points, to protect the compressor.

Well, you do when it isn't draining properly. If it does drain ok then the air is dryer and won't mist until you've breathed out more water vapour.

I've seen cars with drain tubes that should leak the water out onto the road, but mud has blocked the road end of the tubes and the water just fills the tubes and then is pitched into the footwells. The damp carpets this causes ensure a rapid misting up in winter at the drop of a hat.

Mind you, aircon / heating etc, does all work differently to the old heater only setup, and you can get all sorts of unexpected behaviours. Rapid misting is definitely possible even where there isn't a problem.

It is French tho.