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I've always thought I'd teach myself auto A/C service...one day. Well, that day has come.

My '08 9-5 has zero pressure in the A/C circuit. I know that because my first diagnostic test was to depress the high side Schrader valve with the engine off and...nothing.

I noticed the A/C was very weak last fall and then parked the car for about 10 months because reasons.

So I'm about to buy a manifold gauge set and a vacuum pump and get to work. Are there any known points of failure I should look first? Thanks.
 

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Well, I'm answering my own question here. From another thread: there are 3 areas that are prone to leaks. The condenser at the front of the car ( looks like a radiator) which is prone to damage from stones and chippings/also corrosion. The compressor shaft seal and the pipework/dryer at the front of the car.

Now I remember seeing a small amount of greenish fluid dripping on the passenger side of the engine compartment before I parked the car last fall. I guess I'm going to be looking at the compressor shaft seal.
 

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I never really see any common failures really. but often times on any car its just a loose schreader valve. Generally just follow all of your ac lines and check your condenser. The condenser sits infront of your radiator and will be the first thing you see. What your looking for is a dirty oil buildup. if none seen it could just be a schreader valve.

Some things is to grab a can of 134a at autozone. They take roughly 1.7 lbs of it. Feel free to convert that to oz. Get some ac dye. Pull one of the schreader valves out and dump about an ounce of dye in it. Or get the harbor freight ac dye injection kit. You can replace the schreader valve(s) for good measure. but after charging it. But then you can use a black light and yellow glasses and trace the ac lines looking for a leak.
 

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Agree with above, first call - put dye in to find leak. Be advised its filled by weight, not pressure, and damage can ensue if its over-filled. Even if one does know the weight of one of those refill cans, one doesn't know how much is already in it (although I know you are assuming yours is empty).

My 2004 needs a re-gas annually. The indie mobile AC guy found leaks and last year replaced the condenser, dryer and a seal at the compressor. It has still run down after a year - 325 grams came out (825 is full). Couldn't see any leaks so at the moment its a mystery, and he'll come back after a couple of months to check again.

Generally, from what I've read/heard/experienced, the 9-5 system is rubbish compared to earlier Saabs. My 9000 is still cold without a re-gas for the 6 years I've had it, and the 2002 9-3 stayed cold the entire 156 K miles / 13 years I ran it.
 

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Yeah correct weight is 825g which is about 29.1 oz. You can over/under charge your system by a few tenths without much consequence, so ball park (28.8 to 29.5). You can approch this 2 ways and it just depends on how much you want to spend. You can get the cans of 134a, the hose and the fitting to charge your system. Then you'll need a digital scale. You get 3 of the 12oz cans and just suck in 2 of them, then your at 24oz, the 3rd can you can place on the digital scale and suck out an additional 5 oz and call it a day.

Your best bet without an ac machine is to grab a 12oz can and and 18 oz can and throw them both in there. While trying to leave a little in one of the cans. And you can charge by pressure as well. Its not 100% but will work. If you over charge the system and end up causing higher then normal pressure your high pressure cutoff valve will turn your ac compressor off to prevent damage to your ac system. Just watch your pressures. The low side should go as high as 45psi, then drop to 30psi as your compressor cycles on and off. if you go lower then 30psi you undercharged it, over 45psi and you over charged it. If you question my logic... I have a 2 year automotive degree, all of my ase certifications except automatic transmissions, 6 years professional automotive experience, 1 year of that in a shop specializing in volvo, saab, suburu. And I have successfully charged a jeep the same way... no complaints but I'm also more then just a hobbyist as well.

Agree with above, first call - put dye in to find leak. Be advised its filled by weight, not pressure, and damage can ensue if its over-filled. Even if one does know the weight of one of those refill cans, one doesn't know how much is already in it (although I know you are assuming yours is empty).

My 2004 needs a re-gas annually. The indie mobile AC guy found leaks and last year replaced the condenser, dryer and a seal at the compressor. It has still run down after a year - 325 grams came out (825 is full). Couldn't see any leaks so at the moment its a mystery, and he'll come back after a couple of months to check again.

Generally, from what I've read/heard/experienced, the 9-5 system is rubbish compared to earlier Saabs. My 9000 is still cold without a re-gas for the 6 years I've had it, and the 2002 9-3 stayed cold the entire 156 K miles / 13 years I ran it.
There should be no need to recharge your ac... ever... I have seen 70's model vehicles running R-12 blowing cooler then R-134a systems. If you have to recharge, you have a leak. If you cant see a leak, then its probably your evaporator core. There is only 2 ways to check that... AC sniffer pointed at the air ducts, and remove your dash, so you can remove the HVAC unit to inspect your evaporator core. But most commonly a slow leak can be them schrader valves. After recharging a system I generally blow the fitting out with compressed air, then grab the schrader valve with a pair of needle nose and pull up on the schrader valve.
 

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Had a fail on our 06 wagon in 2018. Found a bracket that supports one of the coolant lines had broken allowing a chafe that put a pinhole in the evaporator. Had to replace the evaporator and recharge to get back in business. In retrospect, realised a rattle that could be heard at start-up was the warning the bracket had failed, but only when the A/C had failed was it clear where the noise had come from.

New Evaporator in place, showing the line that caused the chafe (this is with the fasteners loosened to allow the evaporator to be replaced, it was not this obvious with only the single bracket fail)
276133


The pinholes from the chafe that caused the leak.
276135
 

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Agree with all said above. Investing in manifold gauges and a vacuum pump (as well as safety glasses, if you don't own any) is a must to diagnose.

Since it is been sitting for 10 months, could be a small leak (Schrader valve, O-rings, etc.) that drained it all over 10 months. Sounds like you have dye in the system, so for the heck of it you may want check it with UV light/yellow glasses to see if you pick-up anything obvious. Compressor shaft seal and/or the condenser are prime suspects if the system has completely drained.

You could also use the compressed air trick first to find leaks, rather than using refrigerant. If you have an air compressor that is.
 

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@SAR02Aero:
Interesting and good troubleshooting. I'm sure you had a typo and meant the condenser though, not the evaporator
 

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@SAR02Aero:
Interesting and good troubleshooting. I'm sure you had a typo and meant the condenser though, not the evaporator
Not sure what your referring to, but If I remember right its not a typo. If you have dye in the system and cant see any oil buildup on any ac parts... its probably the evaporator. Yes that radiator looking thing in the HVAC box behind the dash. not too common, but I have replaced a couple of them. They are generally pretty armored because of the HVAC box and don't often fail.
 

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Your pictures show the condenser so I thought you were talking about the condenser.
 

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I couldn't agree more an AC should never need charging, and the 9-3 didn't. But surely that's like saying a tyre should never need pumping up! The AC sniffer idea is one I haven't heard of and I'll interrogate the AC guy next time. He got a visual on the evap core by diving into the footwell, and nothing showed with the UV light. I asked him would the dye simply flow downstream i.e. into the HVAC unit, but he says it would show upstream as well. Hmmmm.

The evap is replaceable without removing the HVAC unit. It slides out the same side as the cabin filter, after cutting the pipes via the fan aperture from above. The replacement is in two parts.
 

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I couldn't agree more an AC should never need charging, and the 9-3 didn't. But surely that's like saying a tyre should never need pumping up! The AC sniffer idea is one I haven't heard of and I'll interrogate the AC guy next time.
Yeah a sniffer is a good tool, especially to identify an evaporator leak. As Kamikaze points-out, you could point it to the vents and see if you get a hit. But a more effective is to stick it in the AC vent pipes under the car as refrigerant gas will come-out this way as well. But I've found that "cheap" sniffers can cause false alarms. For example checking the Schrader valves in the service ports may set-off the sniffer, but when testing them with soap and water there are no leaks to be found.So if you are going to buy one, don't buy the cheapest out there. You get what you pay for!
 

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@SAR02Aero:
Interesting and good troubleshooting. I'm sure you had a typo and meant the condenser though, not the evaporator
Your pictures show the condenser so I thought you were talking about the condenser.
Oh I see now. The pictures are not mine. The pictures are the condenser.


I couldn't agree more an AC should never need charging, and the 9-3 didn't. But surely that's like saying a tyre should never need pumping up! The AC sniffer idea is one I haven't heard of and I'll interrogate the AC guy next time. He got a visual on the evap core by diving into the footwell, and nothing showed with the UV light. I asked him would the dye simply flow downstream i.e. into the HVAC unit, but he says it would show upstream as well. Hmmmm.

The evap is replaceable without removing the HVAC unit. It slides out the same side as the cabin filter, after cutting the pipes via the fan aperture from above. The replacement is in two parts.
No, you got that all wrong... I am serious about AC never needing recharged. Ive seen 50 year old vehicles running R-12 (No longer available to purchase) blowing colder then 134a and never been recharged. A Tire however, is a different animal altogether. Tires will naturally loose air over time. I didnt move my mailbu for over 1 year and all 4 tires had 12 psi. During 100ºF Days the tires swell and turn on TPMS lights. I set my tire pressure every other oil change unless I use the rack at work (Just lazy about it at home)

And are you sure your not talking about your heater core thats removable? I have yet to see a evaporator that you can take out without removing the HVAC box. The heater core sits right behind the cabin filter. The HVAC box with the evaporator is in HVAC box behind the glove box. This picture kinda gives you a better idea.

As far as the sniffer goes... there is cheaper... but........ Snap-on Store
 

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Now that's a nice sniffer but way-out of my price league, unfortunately!
First off I should mention that AC is heaver then air... so if you suspect a leak at a connection... then hold the detector below the fitting in question. The schrader valves you just stick on the edge of the hole.

Well there is this one. But you get what you pay for. Will this work... yeah... but you get a lot more false positives. You can blow on it and set it off, bump it and set it off.
Search Results For "Refrigerant Leak Detector" - $70
Electronic Refrigerant Leak Detectors - $250
Great price on Mastercool 55900 at NationalToolWarehouse.com -$150
MCL55900 - IntellaSense II Leak Detector - Cornwell Webcat - $274
 

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Good points, hold detector under the pipes/fittings, etc. I already bought one on Amazon a while back for $70 or so, if I remember well. I'm just a flimsy weekend warrior and not a professional (by anyyyyy stretch of the imagination, may I add) like you so it serves me well so far and saved me money already as I found leaks on first use. I'm an office dork (Sales) by day, garage warrior on weekends / nights!
 
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