Diagnosing AC system failure?

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tl;dr: the AC hisses, but doesn't cool; what should I do?

My Accent's AC went out. It's summer, and even driving with the windows down on the interstate doesn't cool the interior down that much. The dealer said it would be $108 to do the gas flow leak inspection. Here's a video of the noise:
https://www.youtube.com/watch?v=BU997mQN4x4

Should I start replacing every single part in the system? Is there a cheaper way to go about fixing it than going to a dealer (smaller mechanic shop maybe)? I'm going to buy new parts, it's just a matter of finding what is broken and replacing it (sounds easier than it probably is though). I still haven't done the timing belt replacement, so it might be a good idea to roll this repair into the same huge ordeal.
 
Despite how easy some youtube videos make it seem, a timing belt replacement is an advanced repair. If I was you, I'd get a lot more experience before I tackled it. Especially if it's your only vehicle.

As far as throwing parts at the AC system, that can get real expensive real fast.

Go to an independent shop and get their estimate to fix it.
 
Do you have a manifold gauge set. That is the basic tool, beyond checking the fuse. It could be low on R134a. But its a sealed system, so if its low on R134a you have a leak. You can jump the low pressure shut off and see if the compressor tries to kick in. I assume you have checked the belt?

Beyond the $50 manifold gauge set, things get expensive. A good R134a detector is $200. An evacuator system (to remove and filter, store the R134a) is very expensive.

You fill the system by nn ounces of R134a, and a system to do that properly is not cheap either. Vacuum pump?

Get a manifold gauge set (HF is good enough) and start checking things.

If it looses R134a, it could be (most likely) a bad o-ring, leak in condenser, or the high or low valve.
 
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The cursory test is your pressure, at idle and say, 2000 rpm, with supplemental air flowing across the condenser. And knowing high and low sides is important.

The fact that it hisses doesn't strike me as out of the ordinary, in that many AC systems hiss as they start to operate for whatever reason.
 
The last time I have heard an ac system hiss it was low. Get a manifold set and post pressures and temps. Have an aassistant kick on the ac while its hooked up and see if it only cycles. If its low add until pressures are right....

Or bring it to an Indy shop for an evac, dye, and recharge.

Up where I live the temp swings can really cause a mess with 134a. All summer long it can hold, and come winter parts shrink and not necessarily leak, but osmose. Not a whole lot to do, it leaks too slowly to leak oil or detect, and to truly fix might be a whole system replacement. So once a year or three they are back to get topped off...
 
I would suggest you find a guy to test the A/C system and tell you which parts you need -- then change the parts yourself. You'll have to pay a diagnostic fee, but you'll still be money ahead by changing your own parts. That's what I did one day. The guy told me (in his words) that the compressor wasn't sucking anymore. So all I had to do is change the compressor and take the car back to have the system charged with refrigerant. Easy Peezy.
 
Shade tree mechanics basic how to...

If the system is cool, but not cold, and / or the gauges say you have some pressure, R134a can be added.
Can tap, a gauge, and R134a is all that is needed ...

Can tap with gauge...
http://www.walmart.com/ip/Deluxe-R-134a-Recharge-Hose-and-Gauge/16888796

I prefer to add some PAG oil first, helps the seals and compressor...

http://www.walmart.com/ip/PAG-100-with-ICE-32-Oil-Charge/16888788
(1 ounce PAG oil, 1 ounce R134a, and 1 ounce "performance enhancer")
Only add refrigerant oil ONCE, system will drown!

Attach hose to low side, larger diameter hose. Smaller hose is high side.

If the system is hot, gauge reads zero, compressor not engaging, or the system went hot suddenly, or you have to replace parts-
then by the time you sink money and storage space into tools, beyond this is work for a professional shop.
 
Originally Posted By: Merkava_4
I would suggest you find a guy to test the A/C system and tell you which parts you need -- then change the parts yourself. You'll have to pay a diagnostic fee, but you'll still be money ahead by changing your own parts. That's what I did one day. The guy told me (in his words) that the compressor wasn't sucking anymore. So all I had to do is change the compressor and take the car back to have the system charged with refrigerant. Easy Peezy.


You got lucky there. I would expect most shops to take the shotgun approach and just want to replace the entire A/C system, except for the evaporator. You know, since they hate to actually diagnose stuff and it's more money.
 
Unless you see evidence of PAG oil leaking from your
system I would NOT add any as it is very common for the
refrigerant to seep out very slowing over time but the oil molecules are too big to leak out. If you just need to top off with r134a use a can with only refrigerant in it and NO additives, stop leak, or oil.
 
Originally Posted By: mattwithcats
Usual place for A/C leaks is the Schrader Valve.

A few drops of soapy water on top of the valve, look for bubbles....

Tools are made that allow you to replace without having to remove all the refrigerant from your A/C system.

http://www.amazon.com/dp/B002G1UNUS/ref=...d=IFO4SHV5OR1D9


The high side service port on some systems has this little teflon ball check valve deal instead of a Schrader that I have seen leak. It is a rather asinine setup, because it is not serviceable, and you must replace the whole high side hard line.
 
Check the clutch on compressor at the wheelie. If it's not engaging compressor can't work. If you find the coolant has leaked out, they make a dye you can push through system with a partial recharge to help identify any leaks. I'd check some parts stores for lender tools. Some of them will lend you specialty tools with a credit card or deposit down. AutoZone at least used to do that.
I wouldn't buy any parts at AutoZone though. Buy those at Napa. Youy could buy some oil or some miscellaneous thing at other parts stores if they happen to have a vccum pump or gauges etc. To loan ya. Just to not feel like your just taking lol. I use to do that to show appreciation. Sorry if I'm insulting your intelligence here. Hard to know how knowledgeable a guy is by just a few post on a forum lol.
 
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Is it just blowing out warm air or is it seeping air out? And if just seeping is the air still cold?
 
Is it just blowing out warm air or is it seeping air out? And if just seeping is the air still cold?
 
@Leo99:
Yeah, I haven't even figured out totally how to immobilize a car to change the oil. The timing belt is probably several months in the future at the rate my research has been going (I'd like to change the plastic seal, too, but that requires re-timing the exhaust as well).

Any specific things I should look for in an independent shop? I'll probably check out Angie's List; worked well enough for getting the muffler repaired. I don't think there's going to be anyone advertising their services for AC in particular--it's not that specialized afaik.

@Donald:
No, I don't have a manifold gauge set. I'd have to research the different the same way I've researched the other stuff: look up the Amazon ratings (HF's aren't much cheaper; I found a few that were cheaper on Amazon), ignore the ones with a bunch of low star ratings, list the best ones, then check back with the Bob forums. I have absolutely no idea in what to look for in a manifold gauge set (what type of attachments, valves, hoses, vacuum pump vs no pump, etc.).
Here's my starter list:
https://docs.google.com/spreadsheets/d/1...#gid=1584751642

I don't know what a low pressure shut off is, or where it's located on the '03 Accent. Maybe I could find it in the workshop manual. I can probably find it myself; I've spent enough time under the hood staring at mysterious components.

I can't figure out what kind of evacuator I need. The ones I'm looking at on Amazon are either air or manually operated fluid evacuators. I couldn't find one that specified a filter; they look like sealed containters with no filtration.

For a gauge set, detector, evacuator, vacuum pump, one can of refrigerant, and a recharger hose, it would be $346.95 (this isn't counting any replacement parts; this is just for the diagnosis, and assumes that all the parts listed would work for the intended application).

Everyone keep in mind this is a $2700-ish car. Might be cheaper to sell it and get a $5000 car without the same issues, but at some point, I might have to do this kind of repair or get it repaired by someone who knows what they're doing.

@WANG:
Yes, you can hear the clutch engage, followed immediately by the hiss.

@JHZR2:
The coolest it gets is at maybe 3500 RPM, and even then it's barely not-hot; maybe lukewarm. It can hiss, but it's got to cool, which it isn't doing. In order to do the cursory test, I'm going to need to buy some equipment, or pay someone to do the test for me. By high and low sides, you're talking about the front hot end with a pressure outlet for testing and recharging (the condensor) versus the cold rear side (i.e. closer to the blower fan in the passenger side body) where the evaporator core is. I think this video shows where one gauge is supposed to be connected: https://www.youtube.com/watch?v=lPcC0vgq3mM
It could be that the sudden vapor release that I noticed at the onset of the problem was from the high pressure release valve. The car has electrical problems stemming from the battery cables and the instability of the battery; it's possible the AC fan relay was affected somehow and caused it to vent r134a, but it seems less likely than a component failure. I hit a bird last week, and drove through ice, snow, and over an assortment of car parts fallen from everyone else's vehicles from January to May; I guess the condensor could have been pierced; but based on the sudden vapor release, seems more likely to be something further towards the rear of the engine compartment; I was never able to pin down where that vapor came from though.

@hansj3:
I don't know what the pressure and temps are supposed to be. Based on the sudden onset of the problem (like I mention in the video link), it seems more like a component failure than osmosis. A sudden loud hiss followed by vapor emitted from beneath the hood is a pretty good tip-off that something in the system is broken and needs replacement.
This says it's supposed to be 28 PSI with 525-575g of R-134a after drawing vacuum for a half hour on the High side, with the gauge hooked up to the low side:
http://www.hyundai-forums.com/lc-2000-2005-accent/124109-correct-2002-hyundai-accent-c-psi.html

@Merkava_4:
The dealer said the inspection would be $108 for a gas flow test, and $165 for an evaporator purge; is that a good deal or not? I'd like to think I can beat the dealer's price, but then again the dealer is going to know more about the car than an independent. I guess it's worth a shot to ask. Changing out the compressor is going to be almost as hard as changing the timing belt...I might want to ask how much the independent would charge to replace a component I bought.

@bullwinkle:
Where's the condensate drain? A set of glasses, some AC dye, and a UV light would be about $44.65; about the same as getting a cheap detector; might be a decent alternative if the detector doesn't work or if I don't get someone to do the diagnostic for me.

@mattwithcats:
How much of the PAG 100 am I supposed to add before the regular r134a? I don't know where the Schrader valve is for the Accent. Is it the same place as the High and Low side pressure valves?

@GiveMeAVowel:
Other guy says to add it, you say not to. In the interest of everyone getting along happily, should I add a little bit?

@WANG:
I don't know whether it has a Schrader or a ball check valve; I'm going to randomly guess Schrader. Maybe the service manual will say, maybe a parts retailer will say it.

@ronp:
I can hear the reduction in RPM and increase in load. I want to stay away from tool lending though. I've had this one Netflix DVD for two months. :\ The blower is working fine, it's the cooling that has failed. It's lukewarm at best, usually as hot as the engine compartment when I first start it up from idle.
 
If the compressor engages, and is presumably compressing, see if you can get a feel of the vapor/suction line (the bigger of the two) leaving the evaporator. It should be cold to the touch.
 
Originally Posted By: JHZR2
The cursory test is your pressure, at idle and say, 2000 rpm, with supplemental air flowing across the condenser. And knowing high and low sides is important.

The fact that it hisses doesn't strike me as out of the ordinary, in that many AC systems hiss as they start to operate for whatever reason.


if they hiss, they're low on gas.
 
If the compressor clutch engages, how long does it stay engaged? If for only a few seconds, then its probably low on R134a. As you add R134a it should stay engaged longer and longer.

So given its a $2700 car, the cheapest thing to do is to throw in a few cans of R134a a year (but start with one). The best is to get it fixed.

Leaking R134a does contribute to greenhouse gas problems the earth is having, but not to a hole in ozone layer.
 
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