Anyone know if a good write up on how to diagnosis a ac problem on a Subaru? Just blows hot air. I don't know the history of when it last worked.

 

Looking for some type of diagnostic chart to follow, or member write up.

 

Thanks,

 

Geo

Subaru a/c systems are really robust and rarely have failures. i've only really seen two typical failures and one is far more common than the other.

 

they are usually just low on charge...but this is usually caused by a leak.

 

the good news is that the two most common leakage points are the two orings at the hose fittings on the compressor. i suppose it makes sense since those seem the most vibrations and heat cycling

 

you don't get any easier to change or cheaper. one bolt and the hose end slides out of the compressor - pull it out and change the oring. wipe all the dirt/grit off from around the fitting before removing so it doesn't fall down into the compressor.

 

often times if you're really careful you can tell where the leak was (but not always).

 

the autoparts stores sell bags of generic a/c orings. just buy a bag and carefully match them up.

 

last two non-working a/c subaru's i worked on were fixed by these orings. 2003 H6 OBW and a 2000 Forester. ironically i just drove my buddies 2003 home with me today....ice cold A/C - two new orings baby. what is sad is how many a/c systems i've fixed by replacing these two $1 orings....but every person i've ever known that's taken a non-working a/c to a shop is always billed many hundreds to fix it....based on my experience some of those were $300-$600 oring repairs.

 

it's common enough that i would do it, charge it and see if it holds the charge. only takes 15 minutes to do all of that and you'll know if it's something more ominous or not.

 

the other failure item is the compressor/clutch - which will reveal itself as working or not once you charge it.

 

i've never personally seen another type of Subaru a/c failure...except a hole in a condensor...probably a puncture or previous accident.

Let me echo what GrossGary says. In my 2000 4-cyl OBW, all it took was the two o-rings.

Very cool. I will change them. Its nice to hear this may not be a big issue. The car is new to me, tryed it today for the first time..and nothing but warm air. I have an o ring kit here with about 30 different sizes. I have never had ac that Did not work.

Edited June 21, 201114 yr by Rpm90001

Unfortunately mine was the leaky condensor coil .

 

But its making cold again, wifey is a happy camper

I have an o ring kit here with about 30 different sizes.

i always get the a/c oring kits - they're green so i guess they convinced me they're different . not sure if it matters though, but might want to check. i highly doubt it'll matter any time soon.

 

if you just charge it it'll work fine. so charge it to make sure you got the leak fixed then if you want it professionally vacuumed and charged do it once you verify it's not leaking any more after a few days.

 

where was the condensor leaking? only ones i've ever seen leak were in an accident or punctured. they're all aluminum so they don't typically corroded or rust to the point of leaking. i'd like to know where the weak point is if one can just leak due to age.

Edited June 21, 201114 yr by grossgary

Very timely that this is posted now. My 99 OBW A/C just went out recently. I charged it with a can of 134, but that only worked and lasted for one day. The following day, the system was back to putting out only warm air. The compressor is not turning on, because of low 134 pressure.

 

I will take your advise and change out the two O rings, and hope for the best. I was dreading spending hundreds on getting it fixed, as no matter what, any shop is going to charge minimum of hundreds to fix any A/C system. They also like to add new parts to a system that are not broken.

those orings or a compressor has fixed every single non-working a/c system i'v ever fixed (and it's been quite a few).

 

i've replaced two condensors - but i hardly count those as diagnostic repairs since they were due to puncture/accidents.

 

subaru a/c systems don't seem to have too many failures.

 

there are some newer ones i think that has a sensor go bad on them - the sensor on the compressor i think subaru has a technical service bulletin about it. but i think that's a 2000+ model.

My compressor recently kicked the bucket. Wouldn't engage no matter what I did. Replaced it with a rebuild model, $400. Oof.

Are you guys buying the can-and-hose kit or the still somewhat cheap gauge kit?

 

 

Dave

Are you guys buying the can-and-hose kit or the still somewhat cheap gauge kit?

 

 

Dave

 

Yea, I use the can-and-hose kit. Latest version has a spring loaded squeeze handle control attached to the hose. Seems to work okay.

There is one more A/C failure that first gen legacys can have that I have seen at least a few people experience (myself included):

 

Thermoswtich behind glovebox stops working, either causing the compressor to not cycle at all or to work intermittently.

 

not sure what year/model your subaru is but I agree a leak is definitely the most common failure, so start with that.

I went out to look over the system to see if anything stood out. I took the caps off both hoses and noticed small bubbles of green liquid in one of the Schrader valves ( if thats what they call them for ac) Looks like the previous

Owners may of had some type of dye in the system. I looked all over for any dye and have not found anything, looks like the valve is leaking. Is their a seal on the valve? Or do I replace the whole stem? Dealer only part? Suggestions more than welcome.

 

Thanks,

 

Geo

some schrader type valves have replaceable innerds- like on a car. You may be able to unscrew the inner portion of the valve and replace it or the little rubber O ring.

I went out to look over the system to see if anything stood out. I took the caps off both hoses and noticed small bubbles of green liquid in one of the Schrader valves ( if thats what they call them for ac) Looks like the previous

Owners may of had some type of dye in the system. I looked all over for any dye and have not found anything, looks like the valve is leaking. Is their a seal on the valve? Or do I replace the whole stem? Dealer only part? Suggestions more than welcome.

 

Thanks,

 

Geo

 

 

 

Pretty sure that you can buy the Schrader valve stem insert from most any auto parts store. You will also need the stem insert removal tool, that is needed to unscrew and remove the stem. Prolly best to telephone a parts store to see if they carry replacement Schrader vale stems and a removal tool, and have both in stock.

 

You may get lucky, and only need to tighten up the leaky Schrader with the tool. I would try that first before replacing the valve.

 

Yes, the green liquid indicates that someone added dye to the system to find where the refrigerant is leaking out. That dye is fluorescent, so a special colored light is needed with special tinted eye glasses to see the dye leakage.

Do I really need the glasses and light, the valve that is leaking is so green you just can't miss it. It seems if it was leaking anyplace else, I would be able to see it. I really stands out, but it was also sealed under the cap. After I drive it, I can pull off the cam a see small bubbles. This would be great if it was the only leak.

Do I really need the glasses and light, the valve that is leaking is so green you just can't miss it. It seems if it was leaking anyplace else, I would be able to see it. I really stands out, but it was also sealed under the cap. After I drive it, I can pull off the cam a see small bubbles. This would be great if it was the only leak.

 

For what it is worth, I searched for leaks with a UV kit. I looked all around wearing the special glasses and special light. I couldn't see any stains that showed leakage.

 

Today, I replaced the O rings on both hoses that attached to the compressor. It is very easy to replace the O rings. As I posted earlier, tighten up the core of the Schrader valve where you see bubbles. If that fails to fix the problem, then replace the O rings.