2007 Volvo XC70 - A/C Problems, Where to start...? Topic is solved

cmayo1 · Post by **cmayo1** » 21 Apr 2025, 17:01

I just started messing me with my Volvo's A/C. It hasn't worked in the past, so I charged it through the correct port up to about 32PSI. As I was charging it, the A/C compressor kicked on. While the A/C is running, I can hear a hissing under the dash that stops when i turn the A/C button off. It also does not continue when the car is off.

The temperature is not cold. At all. I do feel some conditioning, but nothing cold. I let it cycle for a good 10-15 minutes before shutting it down. I did some light research before posting this and here are some thoughts I have.

1. The knobs or themistor on the climate control. My fan knob for a while was not changing speed when rotating it. That was fixed by just spinning it back and forth a bunch over a long period of time. I haven't really done that with the temperature knobs because it's been cold out and I've used the heat. Could that be part of the problem? The knob thinking it's set to, idk, 74 when i sent it to 60? At the same time, my thermostor is probably filthy so I will look at that.

2. My radiator fan is not working. Thing has had so many heat cycles that it crumbles in your hands with the slightest touch. It doesn't spin, but I've never had the car overheat

3. I have an EVAP code (P0456). I think that the EVAP temp sensor comes into play somewhere, but I do have a leak near my gas tank so it's most likely that.

Thoughts?

Thanks!

Post by **br0dy519** » 21 Apr 2025, 20:53

You have a major refrigerant leak. Get a UV light and check to find where it is. It is possible you may have to shim the compressor as well, look into the breadclip/ziptie trick.

Your EVAP code has to do with the emissions system, not the A/C evaporator temperature thermistor, which can ohmed out easily.

Your radiator fan is a separate issue that should be addressed.

dikidera · Post by **dikidera** » 22 Apr 2025, 01:06

No special coloring required for UV light? I have the same issue as OP. I basically over some span had my refrigerant leak out last year with hissing behind dashboard but only for a few moments at a time. With the heats now, it has become unbearable in the car, at the same time any charging which costs $$$ will simply leak out again.

Post by **abscate** » 22 Apr 2025, 03:28

You will hear hissing in front of the dashboard during normal AC operation as the refrigerant equalizes pressure between high and low side , with the engine off. Any refrigerant leak you can hear will discharge the system in minutes.

Post by **br0dy519** » 22 Apr 2025, 05:01

These cars shipped with UV dye added to the factory charge I believe, there’s a sticker stating it on mine.

Post by **vtl** » 22 Apr 2025, 10:07

Get yourself A/C kit with gauges and vacuum pump like that: https://www.amazon.com/VIVOHOME-Manifol ... B07LBLDZ89 You are supposed to vacuum the system very well in order to evacuate all the trapped moisture before adding new refrigerant. If it sat open for too long you need to replace A/C dryer as well.

Hissing is ok, this is expansion valve working. No hissing under the dash = dead valve.

Do your HVAC actuators work? When you put it to full hot, does it get hot? Does it get at least not hot in full cold?

Having engine fun running is critical for A/C to work properly. If yours is broken you can use a floor fan in front of the air dams in the bumper. Keep spraying water on the A/C radiator to make it cooling more effectively.

Use DiCE/VIDA to read evaporator core temperature. It should go to almost freezing point.

ortho stice · Post by **ortho stice** » 23 Apr 2025, 05:14

No fan means no air over the condenser when the car's not in motion means no cooling is going to happen. Plus your pressure's going to go pretty high, I'd imagine. Fix your fan first of all.

cmayo1 · Post by **cmayo1** » 23 Apr 2025, 16:46

Thank you all!

Lots to do. I'll probably take care of the radiator fan first since that's more vital than my pit stains. I was hoping this was something easy but is it ever? Once I get that fan, will probably have to go to a junk yard, I'll think about getting that AC kit.

The thermistor did have a bunch of dust built up around it (see attachment), but still not cold air. The air is not burning hot like on high heat, but its definitely not cold and doesn't feel conditioned. I was also sitting in my driveway rather than driving, so my broken fan doesn't help.

Interestingly enough, while I was disassembling the unit and fumbling around, I bumped the AC on and it felt cooler than post disassembly/dust removal. I'll try it again tomorrow and see if there's any difference, but doubts are high.

Cheers!

cmayo1 · Post by **cmayo1** » 23 Apr 2025, 16:53

Also, does anyone know which one I need? Using car-part.com (see attached; specifically which fan assembly)

Post by **abscate** » 24 Apr 2025, 04:37

Get your part number from the online Volvo web parts store using your VIN , then search the fitment section to learn which cars have thst part. That can help guide your junkyard search. There is no substitute for taking your old part in and matching it to the used part, internet junkyard shopping is hit and miss.