brus brother Posted June 4, 2006 Share Posted June 4, 2006 Is there any rule of thumb as to how long the original factory AC charge is good for. My 2000 seems tepid under extreme heat and I was wondering if it is just "used up" and in need of recharge. Is there a way of measuring the refrigerant oil to determine its' "coldability"? Are the recharge meters/freon cans from Wal-mart as good as any other method? Quote Link to comment Share on other sites More sharing options...
Ranger83 Posted June 4, 2006 Share Posted June 4, 2006 Put a thermometer in the output vents on max. I think it's supposed to be in the 50's. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 4, 2006 Share Posted June 4, 2006 That really depends on a lot of things, including how extreme the climate is (both winter and summer) where you live. In my experience with R-134a systems it is not unusual to have a slow leak of refrigerant that reduces the efficiency of the system. The first test is to run the system while the engine is idling. Put the vents on "recirc" and the fan on high. Put a thermometer into one of the center vents and measure the temperature of the outlet air. The outlet air should be 25 to 30 degrees F colder than the ambient outside air. If not, then your system is not working properly. Next test is to do the thermometer thing while driving on the highway, where the engine is running at least at 2500 RPM. If you measure a significantly different outlet temperature when you're driving (say more than 10 degrees colder than at idle) then you probably are losing coolant to a slow leak. If you have never recharged an A/C system yourself before, I advise you to either get it done professionally or to get someone with experience to show you how to do it, and make sure you have gauges. The days of recharging a system using a sight glass pretty much disappeared with R-12 systems. If you make a mistake and connect up the recharge can to the high pressure rather than the low pressure port, the last thing you'll see is that can exploding in your face. If you indavertently add too much coolant to the system, you'll pop seals in all the A/C plumbing in the car and then you'll have a major repair on your hands. If you have an obstruction in the system and you don't know how to diagnose it by differential pressure, then you'll blow the compressor when you add more coolant, and you'll have an even more major repair to worry about. Other than that, A/C systems are easy to service! Quote Link to comment Share on other sites More sharing options...
subeman90 Posted June 4, 2006 Share Posted June 4, 2006 if it makes you feel better my wifes 99 legacy is a little low on the coolness factor too. I and benebob have both used the "walmart can with the gauge on it" type of recharge and have both had good results. My buddy Ed has done it also to an Audi and something else and he had good results too. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 5, 2006 Share Posted June 5, 2006 I wasn't trying to scare him off -- just to make sure that he was properly careful and sure that he knew what to do before trying it.... Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 5, 2006 Author Share Posted June 5, 2006 Did the Walmart charge help or is tepid the norm for those years? As for Wayne's caveats, I do prefer to avoid shrapnel injuries where possible so if someone can point me to the low pressure side, it would be appreciated. Also, is there a need to remove/evacuate the old oil or is this simply a process of topping off what refrigerant/oil has been dissipated or used up? It strikes me as odd that I never have to recharge my refrigerator... if it makes you feel better my wifes 99 legacy is a little low on the coolness factor too. I and benebob have both used the "walmart can with the gauge on it" type of recharge and have both had good results. My buddy Ed has done it also to an Audi and something else and he had good results too. Quote Link to comment Share on other sites More sharing options...
subeman90 Posted June 5, 2006 Share Posted June 5, 2006 I could be wrong but isn't the high side and the low side different sizes making it almost "fool proof"? If not the caps on inputs have letters on them L and H As for did it help???? I didn't do it to the legacy yet and on every hot day we have around here I get reminded of it from the wife. I did it to a 95 OBS and yes it did help a lot. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 5, 2006 Share Posted June 5, 2006 the ones that i've seen have different adapters, so it is mostly full proof from what i've seen. this is for 134a and 12. i've had no problems charging my own, it's very easy. i have a vacuum puller as well to "do it right" if need be. i'd imagine if you had all the tools available to an a/c tech, they would have high and low side adapters of all sorts and in the hands of a non a/c expert like myself it would be easy enough to accidentally attach to the low side port. but if you're buying a can to charge with, it's going to have the right low side port fitting on it. it will be hard to get the "perfect" amount of charge in there without gauges, but my friends and myself have never had any problems adding some charge if needed. make sure everything else is working fine (the fan and a/c clutch) before mindlessly recharging. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 5, 2006 Share Posted June 5, 2006 I hadn't considered that the WalMart special would only come with one fitting. I guess it is virtually foolproof, but I'll bet there's at least one fool out there who would prove me wrong some day (I acn imagine somebody fashioning an adapter to connect up to the high side just because they wanted to make sure that both sides were charged up!!) Anyway, as far as needing to take out the old refrigerant -- you don't have to unless there is a serious leak in your system. As long as the "OFF" pressure in your system is higher than normal outside air pressure, you'll not have any air in the system - just refrigerant. So grab your WalMart can, hook it up, follow directions, and charge away. If you don't have any gauges then monitor the outlet air temp as you charge, and as soon as it feels cold enough to you then stop adding refrigerant. Remember, more isn't necessarily better, and too much in the system is likely to blow seals. THe reason your home fridge doesn't need a periodic recharge is that most of the fittings are brazed together rather than put together with flanges and O-rings. So they don't leak as often. Not to mention that you don't take your fridge out for a spin and bounce the #@$$ out of it over the roads daily! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 5, 2006 Share Posted June 5, 2006 Not to mention that you don't take your fridge out for a spin and bounce the #@$$ out of it over the roads daily! quit making me laugh at work!!!! ha haaaa!!!!!! Quote Link to comment Share on other sites More sharing options...
nipper Posted June 5, 2006 Share Posted June 5, 2006 there is no such thing as fool proof, if there was there would be no need for americas funniets home videos. Original question. Refreigernat does not go old. Rubber o rings do. 90% of the time a leaky o ring is the cause. Also new refridgerant is not as good as freon, so it takes longer to cool a car down, and feels really poor at idle. nipper Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 5, 2006 Share Posted June 5, 2006 good point, your charge is'nt "used up". it either stays in the system and works or it leaks and doesn't. if it's still working a little bit, it may be that the leak is leaking down to a low pressure and then it holds. if you charge it, the high pressure may cause it to leak again back down again to where it's at now. leaks don't often go away on their own. check out howthingswork.com if you're curious how the charge continuously cools. Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 5, 2006 Author Share Posted June 5, 2006 Then if a leak is possible, would the refrigerant with leak additive be the ticket? BTW, I checked and the low and high connections are marked with... get this... L and H. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted June 5, 2006 Share Posted June 5, 2006 look at your L and H ports and see if it looks "wet" down inside the valve stem. use a flashlight to peak down there. if it does, it would be worth the 50 cents to replace the valve stems or at least tighten them. they have seals at the base and are a very common cause of leakage. funny thing though....i never see "cheap" a/c fixes when talking to others but i know for a fact that these valve stems leak and need replacing.....so how many $1 fixes plus charging end up being WAY more is what i'd like to know! i've stayed away from the leak additives myself, maybe someone else can comment on that for you. i replace the orings and valve stem cores instead. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 5, 2006 Share Posted June 5, 2006 look at your L and H ports and see if it looks "wet" down inside the valve stem. use a flashlight to peak down there. if it does, it would be worth the 50 cents to replace the valve stems or at least tighten them. they have seals at the base and are a very common cause of leakage. funny thing though....i never see "cheap" a/c fixes when talking to others but i know for a fact that these valve stems leak and need replacing.....so how many $1 fixes plus charging end up being WAY more is what i'd like to know! i've stayed away from the leak additives myself, maybe someone else can comment on that for you. i replace the orings and valve stem cores instead. leak additives BAD! first off once the rubber oring go bad they go bad. No way of using an additive to swell them up. The additive can clog up the internal parts nicely of an AC system (receiver/drier and the expnasion valve). I have yet to see one that workd for more then a season. nipper Quote Link to comment Share on other sites More sharing options...
avk Posted June 5, 2006 Share Posted June 5, 2006 A new product recently hit the market: Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 5, 2006 Share Posted June 5, 2006 I second nipper's comment. Anti-Leak additives are just like radiator Stop-Leak. You can use them if you dare -- but you're often asking for trouble! There is another kind of additive, a dye marker that allows you to see the source of leaks more easily (it looks like flourescent paint when it leaks out of a faulty connection). That you can use if you think you have more than a slow leak, and if you think it is confined to only a couple of joints. However don't get those additives mixed up with the idea of lubricant additives -- a lubricant suspended in the refrigerant is ESSENTIAL for proper A/C operation. It keeps moving parts from seizing up and also keeps the seals wet, which keeps them from drying out and cracking. BUT- if all you are doing is adding replacement refrigerant to a system that has a slow leak, you don't need any extra lubricant. There's enough in the system already to keep things slick and happy, unless you've had a massive seal failure and everything's leaked out of your system. If you're still getting some cooling, that is not the case for you. Bottom line, add a small can of R-134a and see how much cooler it gets. Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 8, 2006 Author Share Posted June 8, 2006 OK, used the Walmart gauge/hose and screw on can (pretty straightforward) and it was low. Added almost 1 can to get it just into the low end of the full range and then it didn't want to take the remainder of the can. Do these cans normally empty completely or is there an equilibrium point where the pressure in the system is the same as the pressure in the can and it stops taking more oil/gas? It definitely seems to be cooling better and I managed not to sacrifice any animals in the process. Quote Link to comment Share on other sites More sharing options...
avk Posted June 8, 2006 Share Posted June 8, 2006 The instructions that come with the kit do not tell you that lower temperature means low pressure. A good system can operate at as low as 20-30 psi on the suction side. On the colored gauge, that would be near the bottom of the scale. They also don't tell you to purge air from the hose, although some kits come with a pre-attached hose already fileld with refrigerant. Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 8, 2006 Author Share Posted June 8, 2006 It wasn't the preattached hose but rather hose/gauge and separate bottles. So, does the system first suck air out of the hose before it starts pulling refrigerant from can? This wouldn't seem ideal. How would you purge air from the hose? The instructions that come with the kit do not tell you that lower temperature means low pressure. A good system can operate at as low as 20-30 psi on the suction side. On the colored gauge, that would be near the bottom of the scale. They also don't tell you to purge air from the hose, although some kits come with a pre-attached hose already fileld with refrigerant. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 8, 2006 Share Posted June 8, 2006 you didnt purge the lines of air? You should of also held the can upside down to help get all the liquid/gas out at the end. How is it blowing now? nipper Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 8, 2006 Author Share Posted June 8, 2006 Followed directions. Run AC on high. Attach hose/gauge with quick connect to L side. Read pressure (in low range). Disconnect from L port and attach can. Reattach quick connect and kept filling and checking and as per instructions kept can upright. Gauge read just over 25 (just into the OK zone)and when I disconnected coupling and detached can, a small amount of gas and oil remained and was discharged from the can. There was no instruction on purging the line though in hindsight I could have pulled the trigger and release the valve in the quick disconnect coupling thereby assuring gas in the line... next time. For now, it seems to be running cooler but then again Nipster, I'm just across the Sound here in CT. and it's pretty darn cool today. Just spoke with Interdynamics/manufacturer and was told there is no way/need to purge their 11 inches of hose... Space Shuttle Challenger (o-rings??) Go with throttle up... Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 8, 2006 Share Posted June 8, 2006 You'd purge the air by giving a short blast from the can into the hose (yes, that means a little of the refrigerant will be lost to the air) and then quickly making the connection to the Low Pressure fitting on your A/C system. Also, I've noticed that with those cheaper hand-recharge kits sometimes the equilibrium pressure in the A/C at idle is too high to take all that the system needs for a full charge from the can. There's a trick that you can employ to suck a bit more into the system. Just reach over and open the throttle a bit - enough to bring the engine speed up to the neighborhood of 2000 - 2500 rpm. That will drive the compressor a bit faster and the pressure in the low pressure side will drop - sucking out a little more from the supply can. Whether that is enough to bring your system back to where it blows cold at idle is entirely dependent on whether too much outside air has been introduced into the system -- which can happen if somebody else tried to charge it up and didn't know hwat they were doing. usually, unless the system's been really improperly treated, the "fast idle" trick will give you all the refrigerant that you need. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 8, 2006 Share Posted June 8, 2006 Nipper - you need to be careful when you advise someone to invert the can. That's OK when the can is nearly empty, but it is a definite no-no when the can is near full. inverting the can brings liquid refrigerant into the charging hose. Too much liquid injected into a compressor that's designed to, well, compress a gas will cause it to break. Gas is compressible, the liquid is not. When you're nearly depleted in the can, it is OK to invert, since most of what then comes out of the can does instantly vaporize as it gets into the A/C lines. Bottom line - invert your cans judiciously - and only in like-minded company! Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 8, 2006 Author Share Posted June 8, 2006 The manufacturer's rep also stated that the ambient temperature would also affect the gauge reading which would be lower on a 65 degree day like today than on a 90 degree scorcher. Thanks all for the input and thorough discussion. I hope it helps someone else when they go searching here. Quote Link to comment Share on other sites More sharing options...
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