[CBecker]

1997 Legacy Wagon 2.5i, if it matters...

When I turn on the AC or set the diverter to DEFROST, the AC fan turns on, but the air doesn't get any colder or dryer.

From the front passenger footwell I hear a fan and what sounds like a vacuum leak.

The previous owner reported that the AC was anemic and appeared to have a leak, but no leak was found via an UV dye test.

The last time I had a mechanic look at it, he said he got cool air out of the vents (but not cold). Now I get no change...

I'm contemplating having someone rip out the entire AC system and replace it, but I don't know if it's worth it. I'm also getting the itch to upgrade to a 2007 or newer Outback-- should I get the AC repaired, or get a quote and adjust my asking price?

 

[Startiger]

I would start with one of those Do-it-yourself AC repair kits. The type with a bottle of refrigerant, gauge and hose that you can get for ~$20-30. Start by using it to check your coolant level and then add coolant if it needs it. If the system has a leak, then keeping the coolant level up will help a lot.

example:
[ame]http://www.amazon.com/SubZero-Synthetic-Booster-Reusable-Recharge/dp/B0002KKLJS/ref=sr_1_4?ie=UTF8&qid=1345117232&sr=8-4&keywords=ac+refill+kit[/ame]

Then I would keep an eye on the coolant level for a few weeks/months. If it keeps falling on you, requiring you to top it off, then you know you have a leak somewhere and then you can start shopping around for AC mechanics in your area.

 

[H-D]

Start with the basics! Feel the hoses where they enter the firewall one should be quite warm/hot, the other should be cool/cold, with a bare minimum of 60 degree differential between the two. Also, carefully feel the hose from the compressor to the condenser, it should be roughly as hot as the top radiator hose (HOT!). Next check the hose from the condenser to the firewall/expansion device, should be approximately 40 degrees cooler. Lastly, check the return hose from the evaporator to the compressor, should be roughly 80 degrees. Look for any frosting along the whole circuit, any showing represents a restriction point. I'd want to find a 'good ol' boy' to check your system's pressures, if he has the gauges & a vacuum pump he's probably good enough. My own suspicions are concentrated on the function/adjustment of the temperature blend door cable. Has the HVAC control been disturbed, or the dashboard R&R'd? There are small metal 'E' clips on each end of the temp blend door cable which CAN effect the air outlet temperatures IF missing or improperly installed. I check the cable operation while lying in the pass. side floor, as I am dimensionally & coordination challenged. With a bright light, you should be able to observe the action of the door's bellcrank as you stroke the control lever through its range. You are looking for lost motion.

 

[H-D]

page 2
I type too slowly!
Disconnect the blend door cable from the bell crank & cycle it to both extremes of its travel while feeling for air discharge temp at the handiest outlet. Improvement? Adjust the cable! No joy? Other (harder to deal with) possibilities: Debris (conifer needles, mouse motels, etc.) restricting airflow through the evaporator. Some kid's girlfriend's necklace falling from the mirror into the defroster outlet. I've dealt with both of these myself. If none of this helps, come on back & I'll delve into the REALLY WAGs. Oh, & remember to adequately support any 'good ol' boys who'll help (like the a-c pressure checker) ...ya never know when ya might need 'em again! Most'll work cheaply, but have projects of their own.

 

[idosubaru]

repair it.

replace the two orings on the compressor and recharge it and see what happens. it's very likely to fix it and work fine for many more years, worth a shot. i have a write up to that extent here:
http://www.subaruoutback.org/forums...efrigerant-repair-5-less-15-minutes-less.html

 

[Greenmamba]

No mention yet if the compressor is engaging, rather than just hearing the AC fan running. The clutch on the compressor - does it engage and then turn with the drive belt?

 

[CBecker]

repair it.

replace the two orings on the compressor and recharge it and see what happens. it's very likely to fix it and work fine for many more years, worth a shot. i have a write up to that extent here:
http://www.subaruoutback.org/forums...efrigerant-repair-5-less-15-minutes-less.html

Thanks... I'll start here and see where that leads.

 

[CBecker]

No mention yet if the compressor is engaging, rather than just hearing the AC fan running. The clutch on the compressor - does it engage and then turn with the drive belt?

Hm. Good question. I'll have to start the engine and check that...

 

[CBecker]

Today's testing results:

I drove the car for over 30 minutes with the temperature set to COLD, fan on HI, and AC on.

Air coming out of the vents was not measurably colder than with the AC off.

I parked the car and checked the two hoses going through the firewall to the evaporator. No significant temperature difference between the two.

I verified that the AC compressor was correctly engaged when the AC switch was on, and disengaged when the AC switch was off.

I looked under the vent caps-- low-pressure valve was dry, hi-pressure valve had a little green liquid in which I saw one or two bubbles surface and pop. Don't know if that was leak or vibration.

I then touched both valves with a screwdriver and vented some pressure.

I then attached a recharge hose and read 25 psi before charging. As I charged to 50 psi (ambient air temperature > 80d F), the compressor started making a new noise, like a metal blade hitting something. Imagine a playing card hitting the spokes of a bicycle wheel, but much higher pitched and metallic. It definitely seems to be a result of pressurizing the system.

Inside the cabin, I looked in the passenger foot well, and verified that the hot/cold gate moved to both stops via the dash slider. Before pressurizing the AC system, I verified that what sounded like a vacuum leak was coming from the evaporator. After pressurization, the vacuum leak sound is gone.

I then drove the car for about 20 minutes, AC on, fan HI, temp COLD. The air coming out of the vents was now cooler than without AC, but nowhere near cold. When I parked the car, the small pipe through the firewall was warm, and the large pipe was just barely cooler, definitely not cold.

Current situation:
AC system pressurized
Slightly cooler than ambient air coming out vents when AC on
Vacuum leak sound gone
AC compressor sounds like it's eating itself.

I guess I'll wait for the system to depressurize again, then go after the evaporator.

Thanks for all the input!

 

[H-D]

I'm not aware of these compressors having a reputation for being overly noisy (like a GM R-4). Look for signs of oily deposits at the compressor front seal, comressor line o-ring seals (which grossgary already posted about), condenser & its connection seals, dryer connection seals, & connections at the evaporator. I've only found evaporator (unit itself) leaks by using a sniffer at the condensate drain tube. Most compressor failures I've dealt with traced back to systems which leaked so much that they had to be 'topped up' more than once a season & then only received refrigerant, but no refrigerant oil. Kudos to Greenmamba for starting at the MOST basic step! I apologize for assuming facts not in evidence!