Leaving The Car Aircon "On"

[nocturn]

Thanks Transam. It doesn't look normal to me but I don't know much about the mechanical side of things.

It's good to get your advise

why would you choose to disbelieve your dealer service people and take the advice of a random individual on the innertube?

[mogandave]

Thanks Transam. It doesn't look normal to me but I don't know much about the mechanical side of things.

It's good to get your advise

why would you choose to disbelieve your dealer service people and take the advice of a random individual on the innertube?

It looked to me like the “random individual” was just confirming what the “dealer service people” had already told OP.

Something wrong with asking around if you think the dealership is blowing smoke up your….?

[NanLaew]

I have seen a 3M branded airconditioner cleaning aerosol in Makro. They also had the 3M branded auto fabric guard which I bought and used since the new truck has 'cloth' seats. I also use Febreze deodorizer once a week. I bought that in Malaysia as I haven't seen it anywhere in Thailand. Great if you have a dog, kids or a sweaty arse.

Back to the OP and whether turning the a/c on and off separately is a good idea. Since battery technology is better and a/c units don't come on with 'full load' when the engine is first started (unless the a/c clutch is buggered), then theoretically, there's no need to turn the a/c on only after you have started the engine. However, I was enlightened to see that turning if off several minutes before stopping the engine is recommended by Toyota. It makes sense as the cold air inevitably causes condensation in the plastic interior duct-work which, if not evaporated off before stopping the fan, would indeed cause the condensation to form water which in turn would encourage mold and hence the arse-like smells. So turning off the a/c but leaving the fan on will be my new standard operating procedure and I can blame any bad smells on the kid or the dog!

As for the water dripping from the underside, this is indeed the sign of a healthy a/c unit. It's when you don't see any water dripping that you should start to wonder. A blocked drain can result in the water backing up inside the evaporator housing or, depending on the plumbing and duct work, inside the car!

Edited July 24, 2012 by NanLaew

[DrTuner]

I recently got a looksee into the pipings of wife's Mitsu Space Wagon as there was a foul smell. The service took the whole thing apart (two AC circuits, it's a big boat) and the source was located to be mold on the front water collector. Cleaning up the water exhaust pipe (there's even a way to do that by poking a rod through a service pipe) and possibly throwing in some chlorine from time to time would've prevented it.

It's the lousy level of scheduled service here that brings problems, not the actual hardware..

[MAJIC]

in theory cars battery is most able to recieve charge while it is still cold, so for the battery ideally one should run the car for 10 minutes (not idle), before switching on any electrical consumers.

but where I come from headlights and rearlights turns on with engine, and a heater is needed to see anything out of the windshield, and rearwindow defroster and exterior mirror heaters and batteries still live 3-5 years

and the ac interior fan uses same power as one headlight bulb, so use the ac as you please

Strangely in a hot climate,the cold air clears condensation.

[DrTuner]

Strangely in a hot climate,the cold air clears condensation.

It's because of the way the AC works. Humidity condenses on the heat exchanger, you'll see the condensed water running out of the drain pipe mentioned before. The low humidity of the cooled air will aid in the evaporation of any condensation in the cooled space, effectively sucking the space dry.

But the moment the AC is turned off and new, humid air enters the system the water will condensate on the cold surfaces. As a practical exercise, just take a beer bottle from a fridge and go outside. This is probably behind the recommendation to turn off AC a few minutes before turning the fan off: it will allow the ducts to return to ambient temperature without gathering a heavy condensation on them.

I never bother with any of it. The automatics on the Mitsu either do their job, which they in general do, or it's off to service once in a while.

[MAJIC]

Strangely in a hot climate,the cold air clears condensation.

It's because of the way the AC works. Humidity condenses on the heat exchanger, you'll see the condensed water running out of the drain pipe mentioned before. The low humidity of the cooled air will aid in the evaporation of any condensation in the cooled space, effectively sucking the space dry.

But the moment the AC is turned off and new, humid air enters the system the water will condensate on the cold surfaces. As a practical exercise, just take a beer bottle from a fridge and go outside. This is probably behind the recommendation to turn off AC a few minutes before turning the fan off: it will allow the ducts to return to ambient temperature without gathering a heavy condensation on them.

I never bother with any of it. The automatics on the Mitsu either do their job, which they in general do, or it's off to service once in a while.

Drtuner,I Bow to your superior knowledge!

[BangkokMatt]

Thanks for clarifying this folks. @Nocturne thanks for your nonsensicle post - the dealership and Transam were in fact saying the same thing

Edited July 25, 2012 by BangkokMatt