Air Con Hissing Sound

[Forummer]

Hi all,

 

There is this hissing sound in my air con (previously dont have) and air con seems warmer but still cool.

 

What's happening? Car is only 6 months old.

 

Need advice.

[Silver_blade]

I guess there is a leak some where in the air con system. Should claim under warranty.

[Watwheels]

U should ask yourself what u did to your car recently. Cannot be the car do things on its own.

[Ahyoo2002]

Very likely somewhere in the aircon system has some leakage.

 

Send it for a check and claim warranty.

[Forummer]

I did nothing to inside engine or air con. My car is totally stock.

 

If I had been guilty of doing something, would I be posting my problem to gain uneccessary attention?

[Vblaster_w211]

Simple. Not enough gas. Just top up. My hissing sound went away also after that.

[Ahyoo2002]

If the root cause is not found, topping up of gas maybe temporary.

[Vblaster_w211]

Hissing is due to low gas pressure.

 

Low gas pressure may be due to leak or just time for normal top up.

 

Hence hissing is not only due to leak. My Honda started to hiss after 4 yrs or so. Time for normal top up.

Edited October 20, 2008 by Vblaster_w211

[Ahyoo2002]

Ok, for my pass experience, low pressure are likely due to somewhere leak. Maybe I am the unlucky one

[Forummer]

Hi all,

 

I just went to check. Pressure was below 200. So top up for now. Agent said wait for a while. If again turn warm, then there must be a leak.

 

Now back to normal for a moment. Monitoring.

 

Thanks guys.

[Yeobh]

I am surprise the Agent AC mechanic is no very professional - he should have use gas leak detetctor or colour dye to try locate the leak.

 

I suspect the pressure relieve valve located inside the evapovrator is faulty.

Edited October 22, 2008 by Yeobh

[Qr25vet]

i thought from my knowledge the expansion valve always produces a hissing sound? and halogen leak detectors not always accurate...of cos those super beak leaks u can smell it due to the PAG oil leaking out

[Enduro25]

now everything budget bdget..pay no rise tat y now they work also work minimal..hehe

[Yeobh]

As far I know not for the evporator expansion valve there is hardly any noise. Of course you get alot of hissing sound from Turbo charger wastegate, steam boiler etc.

A very high class Gas leak detector only can be trigger by R134, R12 and refigerate. A poor quality gas detector ( in our climate) can even be easily trigger by cigarate smoke.

PAG oil is lub oil and not colour dye.Colour dye can only be detect by UV black or blue light

[Yeobh]

If that is the case, such mechs should be give a walking certificate.

[Kianbeng]

Normally, aircon gas no need to be topped up. If Low Pressure, normally there's a leak. If you use for 5 years aircon become not cold, even when they so call "refill" the aircon gas, they actually let the gas out first before refilling. And when they let the gas out, the pressure should still be there, but just that the gas is "useless".

[Dafansu]

thought most people top up at least once per year or per two year

[Kianbeng]

something is wrong? I don't.

 

But when I do servicing on my aircon, it's natural to just "refill" coz they have to dismantle and leak out the gas anyway. But if you see what they do...the first thing is they will check how much pressure is left. If there's low pressure before they do anything, they will tell you there's a leak and will proceed to troubleshoot the leak first.