A/C not cold anymore
 

The A/C on my '02 V70 2.4T with 106K miles is not cold anymore. On the auto setting, everything runs fine, but the air is not cold. Occasionally there is a slight odor like something slightly burning. Is this as simple as a coolant charge, or do I have a larger problem? If it is just a charge, can I use one of the $40 kits from Auto Zone? Thanks.

If the refrigerant is low, there is a leak that needs to be found and repaired. You can use those DIY kits to charge it, but that isn't the way to go because proper A/C recovery and charging equipment is needed to make sure no moisture is in the system, which can damage components.

For about $70-100, get yourself an A/C gauge set if you plan on touching your A/C. it will allow you to properly diagnose a lot of what is going on, and it will keep you safe in the process. Measure the low and high side pressures* at 1500 rpm, the ambient temperature right in front of the condenser, and the vent temperatures. Report back the readings and we can begin to diagnose. As for the burning smell - is the a/c compressor making lots of noise as well?

SOOO many people try to get by with only the low side gauge on those recharge kits, and then wonder why they blew off one of their A/C lines, after adding just a single can of R-134a.

ES6T is correct in that the proper way to know how much refrigerant is in your system is to recover it, weigh how much you removed, and then recharge by weight to the specified capacity. That said, you _CAN_, using a gauge set and cans probably do an acceptable job, as long as your paying close attention to both the high and low side pressures. It's not the preferred approach, but it's an option.

* On this vehicle, the high side port is recessed. Some R-134a couplers are unable to reach the recessed port. For example, one of my high side couplers' service hose connects at the middle of the coupler (looks like a tee). That one will NOT attach to the service port on this vehicle. Another one of my couplers attaches to the service hose at the TOP of the coupler (looks more like an elbow). That will will just BARELY connect to the high side port. I also have coupler as well, which is extra long and easily reaches that high side port.

The system seems to be running properly. No squeaks or rattles, or hums. I recently replaced the blower motor on my '96 850 and all those bugs disappeared. Aside from the smell, and it is pretty slight, and the lack of cold air, the V70 is relatively pristine at 106K. I'll likely take it to my mechanic. He will probably charge the system with a dyed coolant to find the leak I trust him, but I was hoping to save on the labor cost. Thanks for all of your input. Always helpful.

Good call on taking it to someone you TRUST if not comfortable getting a gauge set at this time.

I found out that my problem is the auxiliary fan. Is this a doable DYI installation? The part is pretty expensive, but it does not look too hard to install.

I have a similar problem in my 2006 2.5T. I recharged the system a can (inc gauge) form Autozone. The A/C ran cold for a couple of weeks and then the problem returned, so I have a leak. I also noticed that my radiator fan was on full all the time.

Some investigation suggests that if the pressure in the a/c system drops significantly the fan comes on to cool the engine as it thinks you have the a/c on. Another fill of r134a fixed both problems (fan & a/c) perhaps proving the fan theory.

This is a bummer as even though I soon won't need a/c (Northern California) I still have to address this with a professional as I can't have the fan howling all the time.

Is the auxiliary fan actually burned out (i.e. with voltage applied, it doesn't run), or is the engine overheating?

If it's not the above situation, then I'd question the auxiliary fan diagnosis. There's a pressure sensor in the A/C high pressure line that is used to control the fan speed. At higher pressures, the fan speed is increased. Thus, if low on refrigerant, you'll have low high side pressures, which will result in a slow fan speed, but you'll have poor cooling primarily because you're low on refrigerant. Need both low and high side pressures as mentioned above....assuming it's not a clear fan problem.

Please don't put anything containing sealer into your a/c system unless you want to massively overhaul the a/c in the next year or so (or don't foresee keeping the vehicle that long). The stuff generally appears to work great for awhile, but then takes out your whole system.

As it turns out, I think a previous owner used a sealer in my A/C system like Webbch warned against. The smell I detected was indeed refrigerant. I actually need an EVAP core which I understand requires a full dashboard removal. I also understand that this is a pretty labor intensive project. Anyone have experience with dash removal?

I have done it on other vehicles, but not this one, so can't tell you specifics. Normally, it's a lot of work, but not insurmountable. I don't let it scare me anymore, just roll up my sleeves and have at it. That said, I have the luxury of having a backup vehicle to use, so extended downtimes aren't normally a major issue.

How have you determined that sealer is present, or is it just a hunch? It's not uncommon for evaporators to develop a leak over time. That by itself isn't any indication of the presence of sealer. As for sealer testing, there's a product that can be used to test for the presence of sealer (Neutronics QuickDetect). It only tests for the presence of the harmful type of sealer (the epoxy-like substance, not the seal-swelling kind). However, I haven't had any luck finding a shop near me that uses it, and the kit is prohibitively expensive for a one-time use (something like $300). But if you call around to a number of shops, you might find one that uses it.