I need a bit of help. The car is making a hissing noise like a lorry/bus dumping its air. Ive narrowed it down to a liquid dripping from an AC pipe where it goes into the firewall. It doesnt produce the liquid, therefore the noise, when I dont use the AC. Its not coolant as Ive checked that, its not oil as its a clear liquid and the car doesnt smell of oil. I suspect its condensation from the AC pipe. It then drips onto the hot manifold below and instantly evaporates making the hissing noise. I have never own a zed with working AC until this one, but Ive never heard it make this noise in the year I have owned it. Is this normal or should I be worried? Ive attached a picture to help explain.

 

Hi Tom,

I don't think it's anything to worry about - as you say, it's condensation forming on the AC pipe, then dripping down onto the exhaust manifold.

Mine makes the same noise, particularly on a hot day, after the AC has been working hard to keep me cool ?

I also have a small puddle form under the nearside rear of the engine compartment - pretty much below the area in your picture. The liquid is colour and odour-less, so it's neither coolant, oil or AC gas; so obviously condensation. All cars AC systems dump condensation in a similar way after they've been working hard in warm weather - they just don't all drip onto a hot manifold and hiss!

Thanks Richard, I thought this was the case, but it's nice to have confirmation. I get a puddle exactly where you describe as well. Having never owned a zed with working Aircon I just wanted to make sure!

The aircon drain hose is also in the same location, maybe a little lower, which is just a rubber hose outlet to atmosphere, and is where the puddle under the car will be generated from.

It is very easy to kink it when working near the ECU inside, causing the heater box to fill up with water internally, causing a sloshing noise on cornering. i know this from experience ?

 

I had never noticed condensation build up on that fixing shown. Are you sure there is not a small gas leak through the threads? Maybe smear in washing up liquid or similar and see if you get any bubbles?

On 11/05/2022 at 10:41, craig said:

The aircon drain hose is also in the same location, maybe a little lower, which is just a rubber hose outlet to atmosphere, and is where the puddle under the car will be generated from.

It is very easy to kink it when working near the ECU inside, causing the heater box to fill up with water internally, causing a sloshing noise on cornering. i know this from experience ?

 

I had never noticed condensation build up on that fixing shown. Are you sure there is not a small gas leak through the threads? Maybe smear in washing up liquid or similar and see if you get any bubbles?

I will do that just to be sure today, but the aircon is working great and keeps the car freezing cold