Hi everyone. I recently bought a 95 volvo 850 wagon. The previous owner acknowledged that there were air conditioning issues. The compressor was shutting on/off so I jumped the low pressure switch, checked R pressure and added a can. Now the compressor runs solid and the air is cold, so at least there are no other big problems with the system.

however, I realize there is likely a leak somewhere or I wouldn't be correcting the low pressure. The most common place for leaks, the evaporator, was replaced in 2003 according to a sticker under the hood. Perhaps it is leaking again. When I turn off the car after running the AC, I hear a hissing noise for a few seconds coming from behind the passenger side dash area which is where the evaporator is.

Forgive me if it sounds like a silly question, but is that a normal noise or does it indicate that a leak might be at the evaporator? I've never had a car hiss like that so audibly in the interior, but this car is new to me.

My Volvo S60 doesn't seem to do this, but I've only had that for a couple weeks as well


Thanks for any help!

 

Mine has does the same thing since I got it three years ago. The air conditioner works fine though. But I know the hiss that you're talking about.

 

Greetings from Narita, Japan.

The hissing is probably all right, as long as the evaporator was actually replaced in 2003. It is probably coming from the expansion valve inside the evaporator and releasing accumulated pressure after shutdown.

Keep the AC running and see what happens within a week, then recheck the system pressure. If the pressure drops, however, I would first inspect thealuminum tubing connections for evidence of leak; you can spot it with a film of oil, asR134a (refrigerant, or more commonly known as Freon)is circulating with the oil within the system.

I hope this helps.


JPN

 

Thanks for the replies you guys.

For me, it stopped doing the hiss and it's still cold air blowing out. So the hiss was a one-time, probably normal thing.

I'll check pressure next week, thanks JPN!

 

My pleasure, I hope all goes well.


JPN

 

yeah mine does it all the time, i think it's pretty normal

 

The orface tube/expansion vavle is torn.

That is what makes the noise.

 

sounds possible. expansion device/orifice may have clogged with debris after the evap. change. Once a system is opened and allows outside air/moisture to conaminate system, trash often gets in if it is not properly vacuumed. Unless you want to do a full evacuation and deep vacuum pulled, I'd leave it alone if it's working. Your dryer may also be contaminated. If it works, don't fix it as they say. But expect long term issues a few years from now if you still have it.

 

Its not that type of setup. It is the culinder looking orface tube. There can't be anykind of outside contamination. What causes the noise is that the screen on the end of it tears and thats what makes the noise.

 

is it a big deal?

 

It won't affect anything leaving it like that.

If you replace it you will need to either work really fast or replace the dryer as well.

The orface tube is in the high side pipe in the frame rail between the back of the headlight and the firewall.

 

As an update, it did this a couple times and has since absolutely stopped doing it. The recharge seems to be holding up just fine.

Thanks for all the replies, folks!

 

Glad to be of assistance.


JPN

 

UPDATE here is some pics for you of an orface tube.

One is to show what it looks like.
Then some is of the bad spots. There is 2 bad ones and one good one.
The ones on the left are the bad ones.

 

Thanks Tech, the pics are very informative. Sometimes I wonder why Volvo uses fragile parts like that.

Have a good weekend.


JPN

 

The funny thing is 90% of car company's use the same one!!!