The Nissan Path

Hey guys,

My AC hisses when it's on. Anyone else's do this? It sounds like pressure is being released in varying intensities. It's pretty loud and another one of those things that makes my passengers ask, "What the hell is that?"

It's coming from under the dash somewhere and it comes and goes, louder at times. Not sure if it's the coolant converting to gas, a vacuum line or what.

AC works well.

Sometimes that's a sign of low refrigerant...

mine did the same. Its not cooling, and it hisses.

It was low on refrigerant, as soon as I topped it off, it cooled great and the hissing went away.

I've never had to top off again either, I assume it leaked out of the seals on the compressor, and the new refrigerant I put in has a lubricating leak sealer, I think it makes the seals swell to prevent more seapage.

If there is a leak elsewhere in the system, this may not be the solution.

t

Mine does this only when I come close to or to a complete stop. I've also seen my AC condenser fan doesn't work. Doesn't spin when the AC is on.

AC blows cold when driving, but not when at a stop.

I think you're all correct... it all sounds like what mine is doing. I'll top off the refrigerant and see if that helps.

I'm hoping I don't have the issue with the rear AC lines yet. We'll see.

Thanks much for the feedback!

I think the rear AC lines are aluminum, which means they won't rust, but will rub through pretty easily...

I had exactly same symptoms. Turned out that AC pressure was low. Next I found a leak in rear AC lines under the body. First I was lucky, workshop was able to weld and stop the leak.
2 years later, same problem. Now the AC lines are replaced with somekind of rubber lines.

disallow wrote:I think the rear AC lines are aluminum, which means they won't rust, but will rub through pretty easily...

I do not agree with this, mine looked like rusted (under dirt and salt).

I had exactly same symptoms. Turned out that AC pressure was low. Next I found a leak in rear AC lines under the body. First I was lucky, workshop was able to weld and stop the leak.
2 years later, same problem. Now the AC lines are replaced with somekind of rubber lines.

disallow wrote:I think the rear AC lines are aluminum, which means they won't rust, but will rub through pretty easily...

I do not agree with this, mine looked like rusted (under dirt and salt).

NmexMAX wrote:Mine does this only when I come close to or to a complete stop. I've also seen my AC condenser fan doesn't work. Doesn't spin when the AC is on.

AC blows cold when driving, but not when at a stop.

i had the same ac only cooling when driving issue also. i cheched the ac fan a noticed it was not running. i removed it and wired in a aftermarket 8 inch unit that made a world of difference. i only used two of the four wires from the oem ac fan. taped up the other two.

DanJetta wrote:Hey guys,

My AC hisses when it's on. Anyone else's do this? It sounds like pressure is being released in varying intensities. It's pretty loud and another one of those things that makes my passengers ask, "What the hell is that?"

It's coming from under the dash somewhere and it comes and goes, louder at times. Not sure if it's the coolant converting to gas, a vacuum line or what.

AC works well.

sounds like you might have a evaporator leak since it's loud from the passenger side in the truck . check the freon level and the ac fan to make sure it's functioning properly.

Alrighty, so I put in a full can of coolant and the hissing is gone.

The process was confusing, though. When I connected the gauge, the meter went from "way overcharged" to the low part of "normal" as the compressor clicked on and off. Adding a full can didn't cause the level to read any differently. Makes me wonder how much coolant this thing takes.