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Could I have too much oil in the compressor?
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Harryh
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Jul 27, 2008, 2:51 PM
Post #1 of 11
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Could I have too much oil in the compressor?
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In 2000 I got a 1991 Toyota Camry, 4-cylinder sedan.
Sorry, but I have a number of questions related to the A/C.
When I first got the car, I thought the air was not very cool. Each year it stayed about the same, or a little less cool, it was hard to tell. Anyway, I don’t think there was much of a leak for those years. I am assuming that freon can slowly migrate through rubber hoses. This summer, no A/C. I had the R12 system evacuated for 30 – 45 minutes. I bought one of those R134 refit kits to refill it myself. I assume that the R12 oil does not come out of the system when it is evacuated. I read that the R12 oil would sit in the bottom somewhere and not cause a problem with the R134 oil in the refill can. The system took one 11 oz. can of freon, oil, and sealer to bring it to 33 psi. I’m trying not to put too much pressure on the old system, but I haven’t been able to find what the original pressure was supposed to be.
After about a week the A/C was not working again. I put an 8 oz. can of freon, oil, and dye, and about 9 oz. of freon, oil, and sealer to bring it to 38 psi.
After a few days I checked for leaks with a black light. The only place I could find an indication of a leak was around the R134 adaptor nozzle on the low side. I tightened it up some more.
A week later no A/C. I checked with a black light again, and again the only place I could find was at the adaptor nozzle. I put Teflon tape on it and reinstalled the nozzle.
At this time there is no freon in the system, and I am hoping I have the leak solved.
I am worried that there is too much oil in the system, the original R12 oil and the oil from the cans of R134 that I have put in, leaving less room for freon.
Now the questions:
Does the oil come out when the system is evacuated or the freon leaks?
How do I check the oil? I don’t see any place to get oil out. The only thing I can think of is to remove the compressor and dump the oil out of the places where the hoses connect, but I sure hope there is an easier way.
This would put a lot of air and moisture into the system. After getting the oil out, can I put one can of freon and oil in, use it for a week, and while the A/C is running, open the valve on the low side (or the high side?) to let the R134, air, and moisture out, then refill with freon only? Perhaps after a week do this again and refill with freon only? Could this work? (Is R134 dangerous to the atmosphere?)
(Just in case I don’t have a problem with too much oil.) In doing the R134 refit and putting Teflon tape on the low side, I have had the adapter ports open for perhaps five minutes. Should I do the above procedure to get air and moisture out?
Does anyone know what the original pressure on the low side should be?
Also, I have seen these expensive super refrigerants that claim to reduce the air temperature by 10 degrees or something like that. Do these refrigerants do as they claim?
By the way, I can’t afford to have all the flushing and replacement of parts done when converting to R134. This seems to cost $300 plus. After making sure the leak is gone, I could replace the $42 drier/receiver. I could then have the system evacuated again to get rid of the air and moisture if the above procedure of filling and bleeding the R134 doesn’t work.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 27, 2008, 3:35 PM
Post #2 of 11
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Re: Could I have too much oil in the compressor?
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Arggh! Death kit stuff at work here. You can't tell how much refrigerant is in a system by a low pressure gauge at all - period! Kits lie and don't advise of this.
Orig car held 27oz R-12 and 7oz mineral oil. Most of that oil would still be in the system.
When switching to 134a you would find and fix the leak first. Dump out oil and blow it out if you can and replace the drier which holds some oil.
If not getting all the old oil out I would use just 3.5 oz or Ester oil and no others. You only have guesses at how much oil is in a system untill you know it's all empty or all new parts throughout.
Evacuating does not remove significant amounts of oil.
You retrofit using 60% of the weight of the original known charge - weight counts but watch both pressures. From 60% you can go 1-2 ounces up and recheck till performance is predictable and pressures are in line with the conditions observed. Alone pressures can't tell you it's properly charged unless in conjuntion with all other things working quietly and properly it's a diagnostic and warning for you but not a means to measure the weight of the charge which is all important.
The "last try death kit cans" are just that. If a leak persists with the sealers they use you'll get no help from anyone who does A/C short of now a big job. Sealers can react with moisture or air and harden up inside a delicate system never to flush out so components are trashed. They kinda don't brag about that on containers!
To try again first locate the original leak while there is anything in the system. Then while open you could make a try to blow oil out - trash the drier, add Ester, vac and charge. That $300 bucks is going to look darn cheap pretty soon! >>>> http://www.autoclimas.com/...igerant%20charge.php <<<<
That link will be a world of help for charging up next time from a well held vacuum. You decide on what to do with what's in there now
T
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Harryh
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Jul 27, 2008, 5:05 PM
Post #3 of 11
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Re: Could I have too much oil in the compressor?
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Thanks Tom for that very fast response.
I know I'm going as cheap as I can, but it's either that or no A/C at all. I'm afraid I can't do the correct things and will have to get by with what I can do. (Probably big cost in the future.)
I've read about the types of problems with this simple R12 to R134 conversion. I'm hoping I'll be as lucky as some of the people who have done this and are still going after a couple of years.
Since the loss of refrigerent seems to have been very slow I'm hoping there was no actual leak in the system in the first place, and the refrigerent migrated through the rubber hoses as air will do. I'm guessing that freon also can also pass through rubber, as all rubber is permeable. As far as I can tell, the only leak is at the poor fitting R134 refit nozzle on the low side.
It looks like at this point I should put one more can of freon in to make sure the leak is gone. Then contact this site again to find out how to get all the old oil out and flush the system.
If anyone has more suggestions I'll keep checking for more posts.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 28, 2008, 1:48 AM
Post #4 of 11
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Re: Could I have too much oil in the compressor?
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Ok: The low fitting is probably leaking because the pin that looks like a shrader (tire valve) is too close to the original shrader which is the one holding the charge without leaking. You can soap test where it's leaking - out the cap end or at the threads. It's a larger size schrader tool than the one for tires that backs off that pin - common problem with some fittings.
Dont' add any more crap unless you want to kill it! Dang buddy - it only holds 27oz of R-12 so 16.2oz (measure it) ((weigh the cans)) - one pure 134a can is usually 12oz so you need just 4.2 more and stop there! Drive it around and check performance there. If it's below in pressures and performance you could go up to 18.9 oz charge or add an additional 2.7 oz. Same thing - try it out again for a day perhaps. If still testing lower than expected you can go up to 21.6 oz max. After that it will start blowing warm air again and perhaps blow it up and you won't have to worry about it anymore! Invite the neighbors to watch and have a cook out BBQ to celebrate blowing up an A/C that could have worked.
You can't (yes you can if you have the equipment) measure how much is in the system unless you are counting on the way up. You'll never know the weight of what you release (illegal but I'm not the police) so you are lost without filling it up from empty. If you know whatever is in there now is only refrigerant without air contamination you can just remove the charge till pressure reads about 20psi which is empty if refrigerant - no real measureable weight to that. If any question the system needs to be evacuated and charged into a vacuum. Pump and gauges are rentable.
You need to empty this system when the leak is fixed that you know you have. Other leaks you can deal with later. Use one can of UV dyed, 12oz pure 134a with a can tap and hose. Just that will make some cooling. Then weigh the empty can with the tap and hose on it. That's now your "tare" weight and do the math with another 12oz now just plain (no dye) 134a till you have weighed in the amounts suggested above. You need a scale! Also know that anytime you remove a hose that air goes in so it must be purged - just a spit hose into air before rehooking up to car. No air is allowed or it's back to the BBQ!
So far you need an $11 can of 134a w dye (dye is harmless) and one pure 134a, $7, a can tap with hose, $15, and a gauge (depends on what is available) or rent gauges/manifold set. You do have a thermometer on hand don't you?
If needed you can rent the vacuum pump to start from a vacuum which will work thru the gauges and go back to the cans and tap for charge.
That's the cheapest possible (just a chance) way to get this cooling again.
___________________
Note: Refrigerant gases do leak thru rubber a little bit over long times. R-12 is thicker gas and doesn't leak as fast as 134a so "barrier" hoses are made for use with 134a. Old r-12 hoses should be so permeated with oil by now if not leaking with R-12 they'll behave with 134a.
_____________________
A/C ---- the cheap way is the most costly in the long run. The attempt to save a couple hundred can cost you a couple thousand for just trying and failing! Wonder how many "kits" they would sell if that was on the packaging?
T
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Harryh
User
Jul 28, 2008, 8:52 PM
Post #5 of 11
(9729 views)
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Re: Could I have too much oil in the compressor?
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This is good info Tom.
Your talk about the schrader valve may well be where my problem is. When installing the R134 refit nozzle I saw that it had what looked to be a valve in it. I removed it to make sure it was a schrader valve. It was, and I reinstalled it in the nozzle. Not trusting that it would properly push on the valve in the original fitting and seeing no reason to have two valves, I removed the valve from the original fitting, leaving me only the valve in the R134 fitting. If the R134 refit nozzle is dependent on the original schrader valve to make a good seal then I better reinstall it. I kept it just in case.
The soap test is a good idea. Stupidly I didn’t even think of it. Thanks for the reminder.
From your info that the system originally held 27 oz. of refrigerant I had already calculated that I would put 70% of that, 18.9 oz., into the system to be on the safe side. As you said, I would need to know that the system is completely empty first. If I am not sure of that, I will go with your suggestion of 16.2 oz. Nice to know I could go to 21.6 oz. if necessary. I’m guessing that is 80% of the original, and I agree that I would not want to put any more than that into my old tired system.
I will be satisfied with the system working to only a moderate amount of cooling. I’ll get as close as I can to the 16.2 oz. and try it as you said.
I am worried about air and moisture in the system since I had the low side port open a couple of times with no schrader valve in it for perhaps five minutes. When the leak or leaks are fixed I am considering replacing the drier, flushing the system myself if I can, and having it evacuated by someone. Then start all over on adding refrigerant as per your instructions up to 18.9 oz. and perhaps 4 oz. oil.
Also good to know about some of the tools that can be rented. Now that I live in a Condo, the tools that I need and can store are limited. Also there is only one person I know who still has a house where I can do some limited work in the driveway. It’s terrible how the world changes.
I’ve noticed that under my name on the right side of the screen it says “New User”. With all this talk of blowing things up, I think I will change that to “Demolition Man”.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 28, 2008, 10:12 PM
Post #6 of 11
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Re: Could I have too much oil in the compressor?
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Harryh: That shrader is a problem now that it'a been open. Open is open and you have introduced air - nothing the vacuum pump can't handle. Air just plain can't be condensed and ruins later pressure readings to diagnose what's not working right if needed.
Those retrofit adaptors are different by brand. Some are the actual check valve and some are really just a sleeve to adapt threads to the Acme quick connect. The threads don't make the seal - just noticed you mentioned that in first thread. There should be a rubber "O" ring up inside the new fitting to press onto the end of the original 1/4 npt plumbimg threaded port. Unfortunately then some are tight to that rubber ring the connector pin is already touching the original shrader or if two real shraders (you can blow air thru many of them) then you only want the new one which is a commitment as you can't remove that fitting without losing the charge.
Those come with a drop of thread locker (neat law) so you can't remove them which really stinks because so many of them fail you need to so in a future one put a drop of oil on the threads to defeat that. They will remove if you didn't but they can stress a line/hose and break that! You may need to replace the new one now if this catches you before you get started again. I haven't had much luck fixing the "O" rings in those if they don't behave they are basically junk. Give em hell where you got it for a new one or another brand. I can't get good stuff quick here so I know what the cheap junk is like oh too well.
If it says Inter***amics or Q***t on the package you know you are dealing with junk! Can't help that as that's all that's easily available and they do cost less but doing things over isn't cheaper either.
The oil charge. Without some ester in an old mineral oil system unless flushed clean it's going to be trouble. Too much oil may slug or reduce performance. Way too much oil could choke the compressor.
Charge weights: Repeat.... Start low on % guess of weight. The "sweet" spot will be unique to this car with the components it has now. Hard to resist but know that "more is not better" with refrigerants. If you notice performance dropping off and compressor working harder it has past the right spot and that's when it's hard to remove gas back there where it was best and still know the weight.
It'll work harryh. Just be patient,
T
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Harryh
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Jul 29, 2008, 8:34 PM
Post #7 of 11
(9723 views)
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Re: Could I have too much oil in the compressor?
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You're right Tom, it was one of those Q***t kits.
I put one 12 oz. can of pure R134 in last night. That brought it up to 32 psi. I drove the car for agout 45 minutes today and the air kept working. Haven't had the chance to check the pressure or do the soap test. I should be able to do that tomorrow. If it looks good, I'll give it a week and check again. Then I'll start working on it with the info you have given me.
I'll let you know what I ended up doing and how it turns out.
Thanks Tom
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Harryh
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Sep 15, 2008, 8:54 AM
Post #8 of 11
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Re: Could I have too much oil in the compressor?
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About two weeks ago I finally put a vacuum on my AC system. Apparently, no one rents equipment to put a vacuum on the AC any more because of liabilities. Someone told me about an AC venturi pump from Harbor Freight, so I ordered one, around $15. Then I had to find someone with an Air Compressor to operate the venturi pump. Kept missing getting connected with the guy who had one, so I ended up renting one for $26 and a hose for $6. Then I had to make a connecting hose to go from the pump to the AC low side port. I made the hose with the ability to connect a can of refrigerant at the same time so that it could be added immediately without disconnecting any hoses. A think this is a necessary step to avoid sucking air back into the AC when you disconnect the pump hose and there is a vacuum on the system. It is my thought that the schrader valve is made to close and hold pressure on the inside of the AC system. I worried that with a vacuum on the AC system, if I disconnected the hose from the port the valve would simply be sucked open and air would be sucked into the AC again. I did not add up the cost of parts for the hose, but probably less than $25.
I put about 19 oz. of pure refigerant into the system.
I did not flush the system or change the dryer, so I am keeping my fingers crossed for the future. I was hoping to be able to do these things sometime later this fall, but right now that’s not looking good.
If anyone wants to know how I built the connecting hose, let me know and I will write up a description. At first I thought it would be pretty simple. But then, I realized that you had to keep the hoses from collapsing under the vacuum, and you had to be able to add refrigerant immediately. Various shut-off valves are necessary to do this.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Sep 15, 2008, 6:40 PM
Post #9 of 11
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Re: Could I have too much oil in the compressor?
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Hmmm? It's been about six weeks since your last post. Some comments on just the last one:
Venturi vacuum pumps can rarely pull a full vac You would need to see it hold a steady vac for 1/2 hour or so before charging so I don't have a clue how you rigged up what??
Yes - this could be better than nothing but there's high risk of it not lasting long if it cools at all now as it seems it's been open a long time already - oils make acid when exposed too long.
What's with an A/C hose collapsing under vacuum!? No way - they will hold a full vacuum or they aren't hoses for A/C. This makes no sense as there are moments at low temps that a low side hose would pull a vacuum normally till system shut down when that was sensed.
Moreover the hoses used with 134a must be "barrier" type hose or refrigerant will just leak thru them. They are specific hose, "O" rings if used and crimps mustn't cut thru barrier inside as it's a lining. Molocules of 134a are much smaller than the original R-12 and leak where R-12 wouldn't.
Is this even working for the moment now?
T
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Harryh
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Sep 15, 2008, 9:41 PM
Post #10 of 11
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Re: Could I have too much oil in the compressor?
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The AC seems to be working well so far, but the days are getting cool now and for the past week I only turn it on for a while to see if it is still working.
The venturi pump didn't come with any hose to connect it to the low side port so I had to make my own. It was the pieces of hose I used for this that I was worried about. I put 3/16 brass tube inside of them where necessary.
The instructions that came with the pump said it could put 28.3 millibars of vacuum on the system and you should allow it to work for 5 to 10 minutes. I doubted that I would get even half of that, so I decided to do it for half an hour and allow any air to migrate around the system and evenually out the port.
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Tom Greenleaf
Ultimate Carjunky
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Sep 16, 2008, 5:24 AM
Post #11 of 11
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Re: Could I have too much oil in the compressor?
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 What was that line Harry S Truman used to say? "Give 'Em Hell Harry!"
This is the stuff you needed to rent/buy below and with a can tap with hose to manifold common hose (yellow) you can do magic! No kidding - these are from the link below (I have no financial interest in this) for $75 for gauges and $199 for pump US delivery included.
AutoZones used to rent this stuff for 100% deposits and I would understand if they quit that and don't check up on that which can vary from place to place.
A full vacuum is 29.92 Hg which is "inches of mercury" equates to ZERO at sea level. Millebars is just a way to fractionalize it to split hairs metrically.
************
The idea is that moisture (nor much else) will exist in a state of vacuum. Moisture will actually boil off at wild #s below zero F even in a full vacuum! Moisture is in air - even desert air and it just screws up the show. Water mixed with any PAG oils will make an acidic mix and eat thru parts of the whole system. Oils remain in a vacuum and jury is still out as to whether moisture can be trapped in oils and not escape when under full vacuum. Dessicant will release at least some of the moisture it has absorbed - how much is still an unknown.
*Visualize this: A mayonaisse jar with just refrigerant, just plain air, or a vacuum all look the same. Refrigerant under pressure at given temps will become a liquid and when condensed then evaporated makes the cooling effect. Air and moisture don't do that at temps or pressure realistic for use in air conditioning so they come up with "refrigerant" that will do those tricks. Compressors need to be oiled constantly while engaged and it's just the physics of the gasses that different oils will or won't travel as a foggy mist thru the system while operating. Mineral oil used for most R-12 systems will just sit at low spots and is of no use for 134a but is taking up space. It's not well known how well it mixed with the assorted other oils but is marketed that Ester oil is compatible with remaining mineral oil.
PAGs are moisture absorbing - the others are not. Whatever mix is in this system now is a complete unknow as to how much of what and the only way now to know is to remove all of it by flushing and start with a known oil for use with 134a in the amount suggested by manufacturer.
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Vacuum from any source doesn't matter as long as it has a known #. Pump as shown is made to pull full vacuum and venturi pumps just don't cut it without the most copious amounts of comressed air to achieve that effect. At best they might pull 18Hg. That's close enough for a system to work but isn't good enough for long life. Minuscule amounts of moisture will make frost inside system unseen and cause erratic performance - then with the PAGs the acid just eats thru everything which ends up in a total loss of all parts holding refrigerant - essentially "GAME OVER" for an older car.
A/C is a monster achievment in mobile applications and comensurately expensive.
From what I see you can just risk this as it stands now thru off season and take it up again in Spring - your call. A 1991 vehicle could need about anything at any time by surprise and you either replace the entire system which is impractical or do what you can along the way as you are attempting.
*******
The real deal with vacuum is holding it in a known state with a # to watch. It should hold that indefinately. Gauges allow for pulling the maximum vacuum and locking it there for long term observation which if lost indicates a leak which is sucking air back in starting the whole show over again.
Now keep in mind that atmospheric pressure is 14.7 (+/-) psi at sea level. That's the pressure we are living in and don't think about and for practical other purposed that's our zero line where we live. That's to say that your tire pressure at 30psi is really 47.7 if you put the whole thing in a vacuum - got it?
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With gauges you can observe the vacuum held and weigh in refrigerant thru the same gauges watching the pressures and taking performance observations while doing so. Any less than that is shot gun shooting - hey - sometimes you hit the target!
Note on Schraders: IMO the valve will hold very high pressures and I have noted it does hold the 14.7 psi pressure of atmospher against the full vacuum or it would hiss and gauges would show the loss of vacuum.
This sytem may or may not behave for another season. I understand the prohibitive costs involved to do things better especially for an older vehicle. IMO - it would last longer if existing oils were just blown out of parts and the claimed compatible Ester oil used in place of it. You won't get all oil out so easy and amounts become guesswork quickly.
Stay cool,
T
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