A/C is not cold - 2009 Subaru Forester

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#1
Make
Subaru
Model
Forester
Year
2009
Miles
120,000
Engine
2.5 L 4-cylinder
Hey everyone and thanks in advance for your help!

My friend has a 2009 Subaru Forester and the air conditioning does not blow cold air, it only seems to blow outside air.

Last year the car had the same issue but the A/C randomly started working again.

She's a grad student who can't really afford to bring her car in to a shop so I told her I would look into it and see if I can fix it, but I don't know too much about car A/C systems.

The car doesn't make any odd sounds making me think that the compressor is working okay (though I could be misinformed). Additionally there does not appear to be any refrigerant leaks. The air pressure seems to be normal, so I don't think the blower has any issue either.

Are there any recommendations on how to troubleshoot this issue?

My first though was that the system needs to be recharged or that the evaporator or condenser could be the issue.

Any advice is greatly appreciated.

Thank you!
Steve
 

billr

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#2
There are a couple of things I will suggest now, but real quick you may have to decide if you want to invest in a gauge set (about $50 at Harbor Freight) or abandon this effort. Being able to read both high and low pressures is essential for all but the simplest of A/C work.

Does the compressor clutch come on, so that the compressor is actually being driven? The pulley for the compressor will always be being turned by the belt, don't get fooled by that. If the clutch doesn't engage, compressor isn't turning, you need to check its electrical power circuit, so an electrical multimeter will be an immediate need. Do you have one and know how to use it?

Dig out a UV "black" light from the olden-days and shine it around the compressor and hoses going to it. Refrigerants have a UV-sensitive dye in them that will glow a sickly yellow-green if there are leaks in the system. As a sanity check, to make sure your UV testing procedure is proper, take the caps off of the high/low charging ports and shine the light at the uncovered ports. There is sure to be some dye in those.

Trying to charge with one of those cheapie cans with a single gauge is a "Hail Mary" play. It might work, but it is just as likely to be a waste of time/money that would be better spent on the gauge set, so you can have a decent chance of fixing this. In fact, over-charging with one of those cans can result in poor cooling and just confuse the issue; as well a raising pressure up high enough to stress things unnecessarily.

Whatever you do, do not put anything in there that alludes to be a sealant; not as an ingredient in the refrigerant or as a separate product. A pro shop will probably refuse to touch the system if it has sealant in it; or will jack the price way up to account for removing it from everywhere.
 

nickb2

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#3
I highly recommend what Billr wrote above. Especially those add on cans. They usually have some form of sealant in them. Any pro shop like where I work always take out the sniffer and analyze before doing any AC work. If it has anything else than what is supposed to be in there, we straight out refuse to do the job. Not worth the risk of contaminating a very expensive recovery station.

By law, we cannot empty the system in atmosphere and then proceed to flush the system of contaminants. So a separate station for recovering contaminated freon/r134a is needed and not alot of shops have one. So a specialty shop will be needed, and yes, as Billr wrote, it skyrockets the price.

I rarely see an AC job below a grand. So invwsting in a cheap set of guages and a vacuum pump if you need to open the system is a good investment.

Here is a link to a very iffy kit. https://www.amazon.ca/Generic-Gauge...5RYMBHFEDQC&psc=1&refRID=B2YQZ3XNH5RYMBHFEDQC

You will need to buy three adapters to complete the kit to make it r134a, probably making it the price of this other link. And again, probably only good for a few jobs before the fitting start leaking and gauges crack etc. https://www.amazon.ca/YaeTek-Combo-...TEBRHDMT0GG&psc=1&refRID=7C2HXPRTBTEBRHDMT0GG
 
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#5
For intermittant problems such as these, I will take the time to "train the customer" to make to simple observation of compressor clutch operation. Have her watch the clutch as someone turns AC on and off several times. Then, she will be prepared to observe and report her findings when the problem occurs.
 
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#6
You are very nice to try and help her. But being a novice with A/C, I would suggest that you do not get involved. A/C is tricky and expensive. Having said that, IF you proceed, those on this site will try to assist you.

BTW, every response above I agree with.
 

nickb2

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#8
As the article mentions, some systems disable the compressor via the cycling switch when static pressure is below 25psi.

So reading static pressure with a gauge set is imperative as a first check. Next is to check if the clutch works. You can bypass the ac clutch relay and see if the clutch engages. But doing this does not mean everything is ok, we have not checked the electrical portion of the system before the ac clutch relay. Such as cycling switch, ac head unit commanding it on or off, etc.

Some systems also use a PCM command on also. Most modern cars do now. I have seen some problems where everything was ok on the HVAC side, but the pcm was overriding the system because another portion of the engine was in trouble. In one case, the engine was slighty overheating, the ecm went into protection mode and shut down ac system to prevent further overheating. I merely use this as an example to denote that sometimes, everything can be mechanically sound yet still not perform. Such as a clogged condenser for example. In VERY rare occasions, you may end up having a bad ecm.

In the pdf below is your wiring, note that you will see what I mean by the ecm also controlling the cycling/pressure switch and the ac compressor.

also included a electrical check chart of the entire system. But as Billr wrote, you need a DVM and knowledge of how to use one.
 

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nickb2

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#10
Another thing to consider is ac clutch gap. If the gap has become to large, the electrical force to close it will be to great and you will have an inoperative system. You will notice a rust color on your compressor. Very common on subaru. Watch this video, notice the clutch gap is obviously to large and you can see the rust all over the comp. You can hear the clutch slipping.