Aircon noisy??

[YarisHybrid2016]

Hi,

Earlier this afternoon, I was sat in a car park when I heard a buzzing sound. At first it sounded like the hydraulic pump for the brakes, but it caught my attention because it wouldn't stop.

A bit more moving my head around and I realized it was coming from the air conditioning, so I switched the AC off, and it stopped. I switched it back on again, and whilst I could hear the pump/fan for the AC running, the buzzing stopped.

Not heard it before or since.

Can leaves or debris get in somewhere to cause this? It's the only thing I could think of. Car had been sat about an hour, having been driven for 35 minutes prior to that.

Air con is selected on all the time the car is in operation.

[vivalacoulter]

If it's gone away I wouldn't worry. When was the pollen filter last changed? Could have leaves etc in it I guess. Why always AC on anyway?

[FROSTYBALLS]

Since changing to our latest cars (2015 and 2016) we leave the air con on on both throughout the year. Partly because:

1. it keeps the system seals lubricated - less chance of leaks

2. better demisting in winter when used with heat

3. the latest coolant used in air con - r1234yf - is a currently a lot more expensive to replace than the previous r134a. Believe around five times at present.

R1234yf is a legal requirement in new cars from January 2017, although most manufacturers changed over to this coolant some time before. Cost of the gas will eventually drop - currently gone are the days of cheap re-gassing for recent cars.

[vivalacoulter]

Huh that's something to consider then. With my current Audi I normally just make sure I run the AC once a week.

[YarisHybrid2016]

Frosty gave a more detailed answer than I could, but essentially because I find the car mists up, and I like a cool cabin!

I know it is better for the AC to run, too, so bonus. It also helps prevent bacteria (if your AC smells, get it serviced).

I did blast the heater last week - I hardly use very warm air. It helps keep the system free of bugs.

I read a recommendation that says if you don't use the AC often, run it on max cold for 30 minutes once a week.

[vivalacoulter]

Won't running the AC all the time severely reduce mpg though?

[mrpj]

17 minutes ago, vivalacoulter said:

Won't running the AC all the time severely reduce mpg though?

Severly, no, the extra consumption is negligible. That negligible extra is well worth it for a nice cool cabin and the winter benefits too. Frostyballs item 2. Presumably his a/c is really efficient with that username! Fuel consumption is probably higher if you open window(s) which will "spoil" the aerodynamics of the body.

[monkeydave]

1 hour ago, vivalacoulter said:

Won't running the AC all the time severely reduce mpg though?

thats in the old days of a/c now it is only a tiny amount and a lot cheaper than having a leak and repair from under use