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The A/C in my 20 year old car doesn’t blow as cold as it used too. The system has been untouched since leaving the factory. Other than minor stone bruising on the condenser there is no visible damage. All coils are clean and the fans operate like normal.

Refrigerant must have left the system. Do I need to chase down leaks or am I just dealing with the accumulation of 20 years of inherently imperfect seals? My initial plan was to have the system recharged professionally and see how long the cold air lasts, but I’m beginning to fear that an improper repair will cause more damage than doing nothing.

The vehicle service manual states that oil lost during the refrigerant recovery step must be captured and precisely measured. An equivalent amount of a specific oil must be reintroduced during system charging. My gut feeling is that most A/C technicians would gloss over this step by not measuring/adding oil or using the wrong “universal” type. Also, if I have a slow leak somewhere I’d image oil has been escaping with the refrigerant. How much am I supposed to add if I can’t measure what I’ve already lost? Is the proper next step a system flush to remove all the oil and refill from scratch?

There’s probably a fudge factor and none of this really matters, but maybe it does? Any input would be appreciated.
 

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The A/C in my 20 year old car doesn’t blow as cold as it used too. The system has been untouched since leaving the factory. Other than minor stone bruising on the condenser there is no visible damage. All coils are clean and the fans operate like normal. . . . .
If you have been able to drive an automobile for 20 years and NEVER add refrigerant to the air conditioning system, that is truly amazing. Very few could claim a record like that.

What is the year, make, model of vehicle?

. . . The vehicle service manual states that oil lost during the refrigerant recovery step must be captured and precisely measured. An equivalent amount of a specific oil must be reintroduced during system charging. My gut feeling is that most A/C technicians would gloss over this step by not measuring/adding oil or using the wrong “universal” type. Also, if I have a slow leak somewhere I’d image oil has been escaping with the refrigerant. How much am I supposed to add if I can’t measure what I’ve already lost? Is the proper next step a system flush to remove all the oil and refill from scratch? . . . .
You can visually inspect and feel for oil - dirt along the refrigerant lines. Pay close attention to the crimped fitting where hose meets metal tube.

If the system has been virtually leak free for 20 years, if you have lost any refrigerant oil, it is very minimal so I would not be too concerned about that. You need to attach manifold gauges to check the suction and discharge pressures and equate that to the ambient air temperature around the vehicle. That will help you determine if refrigerant needs to be added or there is another issue.

It is possible that the refrigeration system is still sufficiently charged but an air distribution problem in the HVAC system is not directing cooled air properly.
 

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Welcome to Allpar. A/C service begins with a visual inspection.
You are correct in saying that oil usually escapes with the refrigerant. Do you see any 'wet spots' in the plumbing? Generally condensers get hit with pebbles, joint gaskets can seep and evaporators corrode. Any oily wet spot would probably indicate a leak.
Halogen gas 'sniffers' can also be used to find and verify R-134a leaks.
The proper repair would be to reclaim the remaining refrigerant, open the system to repair the leak, evacuate the system into a vacuum, estimate as best you can the amount of PAG oil that may have been lost and replenish it and then fill the system to the correct weight of refrigerant shown on the underhood label or in the manual.
Too much added oil can be almost as bad as too little oil in the system.
Theoretically, adding or recharging refrigerant to a 'known' leaking system is prohibited and it must be repaired first:
Regulating recharge (at https://macsworldwide.wordpress.com/2016/06/23/regulating-recharge/ )
 

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I'm not an AC technician, but I'd have the system diagnosed and checked by a licensed tech. Freon that has a dye can be added to the system to help identify any leaks. I'd do that first before proceeding any further.

Year, make, model?

Does it have R12 or R134?
 
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Need more info... as stated above.
 

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I was taught many years ago that refrigerant loss in an automotive system could be 10% per year. So an untouched system may have "naturally" lost enough refrigerant to lower system performance. Some newer systems don't lose as much, if any. Usually an area of oil accumulation is the most visible sign, but if the leak is slow enough there won't be any oil escaping. Best course of action is to have the system recovered, pull a vacuum and monitor vacuum decay, recharge with dye added and monitor the system with a quality UV light. I have had some leaks take a day or two to show themselves.
 

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Discussion Starter #8
The vehicle is a 2000 Honda Accord and uses R134a refrigerant. I realize this is a Mopar forum, but it contains the most informed community I’ve come across on automotive A/C systems.

None of the fittings appear to be leaking oil, but I do detail my engine regularly. The condenser is not dented or oily; the only damage is a few rows of bent fins. The compressor is free of oily residue. I’m not sure how to check the evaporator without a borescope, but there isn’t any odor during A/C usage.

My suspicion is that one of the Schrader valves are leaking. After removing the dust caps, the high pressure valve was completely dry but the low pressure valve continued to bubble slowly after 30 seconds. My research suggests these valves are common failure points. I’m hesitant to contaminate the system with UV dye. I know it’s a common diagnostic tool, but I’ve read that the system should be flushed afterwards.

I think my best course of action is to buy the PAG oil specified in my service manual, buy two Schrader valve cores and have the system professionally recharged by an A/C technician I’m confident will do a proper job. Does that sound prudent? Should I do an A/C performance test first? Should I add UV dye when having the system recharged?
 

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UV dye shouldn't hurt the system and can be kept in permanently. I can't see how it could be effectively 'flushed' from the system anyhow.
The Schraders are common A/C leak points. A sniffer may indicate the presence of gas to confirm the leak. Very little oil has likely been lost if the valve is located higher-up in the plumbing.
 

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You have not indicated vehicle odometer miles nor your location. I will assume you are NOT in the "rust belt" of North America as the vehicle body would not survive the salt degradation. You probably have relatively low odometer miles so A C compressor failure is probably not likely???

Any leak if present has to be very, very minute for a system to be operational without attention for 20 years. As ImperialCrown stated any oil leakage has probably not occurred. I would use the services of a professional automotive A C facility (dealer / non-dealer). Put a small refrigerant charge on the system and perform electronic / sniffer leak detection. If no major leaks such as an evaporator or condenser leak or fitting leak, recover the refrigerant, perform a deep vacuum draw on the system and then recharge with proper refrigerant amount. I would NOT add any compressor oil. Do a performance check on refrigerant operation and you should be good for another 20 years.

Incidentally you could have posted your question under the category Non Mopar Tech Support and it would have received the same responses.
 

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I know you shouldn't do this but..........whats is the right way (cheap) to refill the system every summer from a small leak.?
 

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My feeling is that there is no 'right' way. If it is determined that the system needs an annual 'topping-up', then you obviously have a leak. Fix the leak and it should blow cold for years, or until something else fails.
Many owners add refrigerant blindly (without gauges) and the vehicle comes in way overcharged.
If the low side is high, it won't blow very cold. I have no way of knowing how much of what is in the system, so I have to start from the beginning by evacuating and then recharging the system with the correct amount (by weight) of refrigerant.
Then I can diagnose the system to find out what repair it really needs.
 

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Discussion Starter #13
You have not indicated vehicle odometer miles nor your location. I will assume you are NOT in the "rust belt" of North America as the vehicle body would not survive the salt degradation. You probably have relatively low odometer miles so A C compressor failure is probably not likely???
You are correct on both counts. The car is located in Southern California and only has ~150,000 miles. The car is virtually rust-free and the A/C doesn't see a lot of use, even by Southern California standards. I'm just trying to nip my A/C problems in the bud before they grow into an expensive repair.

I would NOT add any compressor oil.
My service manual states to measure the oil removed during refrigerant recovery and add back an equivalent amount during recharging. I found a video on YouTube of a recovery/recycle/recharge machine that follows this procedure. Is there a reason not to add the oil?

I think my hardest task will be to get the technician to inject the correct oil. My manual and compressor manufacturer both call out ND-oil 8 (or its modern ND-oil 12 equivalent). As far as I can tell, it's a double-end capped PAG 46 oil with additives. ND-oil 8 appears to be the only product that fulfills each requirement. I was hoping to buy some online and bring it to the technician, but I'm not sure they'd be willing/capable of injecting a customer-supplied oil.

Incidentally you could have posted your question under the category Non Mopar Tech Support and it would have received the same responses.
Sorry about that. I found my way to this sub-forum via Google, so I'm not too familiar with this site. I was hoping A/C systems were universal enough that I'd fly under the radar!
 

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I can link this thread to Non-Mopar and give it a 2-day re-direct.
If you are concerned about the proper 'Authorized Honda/Acura' service training, procedures and materials used on your vehicle, why not take it to a dealer? Not much more expensive, if any. Look or ask about A/C service specials and coupons.
We used to keep coupons under the service desk if it would help sell a job. If that's what it takes, then it is a win-win.
It is the A/C busy season right now. Do research and consider your best options.
 

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You are correct on both counts. The car is located in Southern California and only has ~150,000 miles. The car is virtually rust-free and the A/C doesn't see a lot of use, even by Southern California standards. I'm just trying to nip my A/C problems in the bud before they grow into an expensive repair. . . .
The fact that the system has been trouble free for so many years is a definite PLUS for you.

. . .My service manual states to measure the oil removed during refrigerant recovery and add back an equivalent amount during recharging. I found a video on YouTube of a recovery/recycle/recharge machine that follows this procedure. Is there a reason not to add the oil?

I think my hardest task will be to get the technician to inject the correct oil. My manual and compressor manufacturer both call out ND-oil 8 (or its modern ND-oil 12 equivalent). As far as I can tell, it's a double-end capped PAG 46 oil with additives. ND-oil 8 appears to be the only product that fulfills each requirement. I was hoping to buy some online and bring it to the technician, but I'm not sure they'd be willing/capable of injecting a customer-supplied oil. . . .
I did some research. ND 8 oil is the specification that Nippondenso (compressor manufacturer) uses in its equipment. This is equivalent to PAG 46 oil. ND 12 oil is the new specification for compressor oil to use with systems that use refrigerant R1234yf and is backwards compatible with R134a refrigeration systems. But ND 8 / PAG 46 is NOT COMPATIBLE with R1234yf systems. So you may and should use PAG 46 compressor oil.

Reference link to refrigerant system capacity and type compressor oil.

Honda Refrigerant and oil capacity charts || TechChoice Parts (at http://www.techchoiceparts.com/refrigerant-and-oil-capacities/honda )

Reference link to discussion about differences in refrigerant compressor oil.

Understanding the Differences Between A/C Compressor Oils - Tire Review Magazine (at http://www.tirereview.com/understanding-the-differences-between-ac-compressor-oils/ )

Manufacturer NipponDenso discussion about refrigerant compressor oil.

http://www.denso-am.com/media/corpo...essor-oil-and-refrigerant-mixing-old-and-new/

An A C service shop setup with the proper recovery and recycling and charging equipment is your best bet. As ImperialCrown mentioned a shop (dealer / non-dealer) with the correct equipment can evacuate any existing refrigerant along with oil. Once the system is COMPLETELY void of all refrigerant and oil, any existing refrigerant recovered will be cleansed of moisture and other contaminants and returned to the system along with any additional refrigerant necessary to bring the system to the correct charge level. The recovery and recycling equipment as it charges the refrigerant can be set to inject the correct mass of compressor oil. There is no guess work involved. Once done you have duplicated the factor fill procedure used when your Honda was built in year 2000. You CANNOT get any better than that!

If you have concerns about proper procedures ( you do NOT want to take short cuts with your A C system) discuss these with the service advisor / personnel at the repair facility. Any reputable facility would welcome an honest discussion about doing the procedure correctly the first time. Problems arise when customers want to do A C work "on the cheap" and short cuts are taken.

. . . Sorry about that. I found my way to this sub-forum via Google, so I'm not too familiar with this site. I was hoping A/C systems were universal enough that I'd fly under the radar! . . .
There are lots of different, meaningful question and answer discussions on this Allpar site. Having separate categories help to keep the vast knowledge of informative discussions organized. And behind the scenes I am thinking that having discussions categorized helps to direct expensive, electronic resources that manage the site directed to the areas / categories with the most activity.

I have posted on the Non-Mopar area with questions about GM vehicles several times. I have received honest, forthright answers just as in the Mopar areas. No one will hang an "electronic SCARLET LETTER" on you just because you post there. :)
 

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Thank you for the help, everyone. I feel much more informed and comfortable going into this repair. Fingers crossed for another 20 years of cold air!
 

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You wouldn't have this problem in Michigan.
There are no Hondas anywhere near that old here!
:)
 

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That must be nice. My vehicles do not make it past 3 years without needing to be topped off. I live in the south-east so I am using my A/C on max 10 out of 12 months a year and on low the other 2 months.
 

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I know you shouldn't do this but..........whats is the right way (cheap) to refill the system every summer from a small leak.?
You don't. You repair it.
 
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you have a 10/15 year old car thats worth $2000 that works great except you have a ac leak. Do you spend $1500 to fix it?
I don't think so.
 
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