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Advice on refreshing/flushing older AC system that leaked

PredatorCoder on Tue July 16, 2013 11:15 AM User is offline

Year: 1998
Make: Honda
Model: Accord
Engine Size: 2.3L
Refrigerant Type: R-134a
Country of Origin: United States

Hi... Being up front here, I'm very new to A/C work and looking for advice. I've been reading heavily on this subject and want to do the job reasonably right. (Certainly, staying far away from the magic stop leak cans!!)

I had a hose leak most of the refrigerant a year ago. A few weeks ago, I had a shop (a national chain store) do a diagnosis and recover the remaining refrigerant; the only fault they found was that leak. After I noticed diminished cooling capacity last year, I never operated the compressor because I had read that this can destroy it due to under-lubrication. Given the age of the car, they suggested just evacuating and recharging for $170. Replacing just that one hose was quoted $200. That sounds really half-baked to me. This car is 15 years old (290,000 miles) and I plan on keeping it for awhile longer. Everything this old leaks and I think it would be wise to refresh/clean/reseal everything.

If I do everything below, I hope it will last quite awhile longer for many more years and see no reason why it wouldn't seeing as the compressor seemed to be running just fine before the hose leaked?

1. Does this part replacement plan sound reasonable?
a. Use Nylog Blue on all o-rings/gaskets/seals throughout the system.
b. Replace all seals on the compressor: o-rings/gaskets/shaft seals. Wipe clean all old oil from parts. Torque compressor to spec when reassembling.
c. Replace clutch bearing.
d. Replace safety valve on compressor with new OEM (it did not blow, but what if it leaks later?)
e. Replace all hoses with new OEM.
f. Replace expansion valve and receiver.
g. Replace binary switch (what if it leaked internally later?)
h. Replace all o-rings.

2. The system has leaked an unknown amount of oil. And perhaps remaining oil has absorbed moisture by now? Plus, it is 15 years old oil... Since proper oil level is critical, it sounds as if I have no choice but to flush everything if I want to do this right. Regarding flushing, it seems as if I would have two options: actually flush the condenser / evaporator or just replace them if flushing is too expensive. Since the compressor did not fail, I doubt that would be a cause for replacement (i.e. excessive debris). Some ideas:
a. It sounds as if the Hecat Pulsator flush gun is the gold standard; it should handle the parallel flow condensor no problem, right? The cost ($350 if you remove the value of included flush) seems steep for a DIY'er like me but if that's what it really takes to avoid trashing the A/C system...
b. Given the cost and reputation of the Hecat flush fluid, it would seem its use would be a no-brainer in this situation. How much flush is needed for this job?
c. Thoughts on a product like this, in this situation? http://www.4s.com/Upload/Four%20Seasons/documents/4S_AC_Flush_Kit_Flyer.pdf It looks much more capable than the MasterCool/Robinair flush guns as it runs off of shop air. But is this enough to do the job, or will I be facing compressor failure in 6 months due to inadequate flush? Saving $200+ on flush equipment would look silly if that happened.

3. Is this procedure reasonable? Regarding charging, my planned procedure to avoid over/undercharge & moisture is as follows:
a. Load 1/2 oil charge into compressor suction, other 1/2 into receiver. Assemble receiver onto system last immediately preceding evacuation.
b. Tools: MasterCool 89660 aluminum manifold gauge set, Robinair 15115 1.5 CFM single-stage vacuum pump, MasterCool 82495 ball valve (for pump isolation), MasterCool 85525 can tap + hose, MasterCool 52220 dial thermometer, digital kitchen scale (it is sensitive/high resolution, I will consider testing for accuracy with calibration weights), common hair drier if needed.
d. Use Johnsen's #6313 R-134a /w dye, and #6312 R-134a (no dye) 12 oz cans (use one can with dye, one without).
c. Should I be using a vacuum/micron gauge or is this overkill? I originally thought it highly recommended but now I sense overkill after seeing no such mention of this being included on expensive Robinair/Mastercool RRR machines.
d. Attach refrigerant can but do not puncture it yet. Open up all valves: evacuate air from manifold and car for 1 hour. Test for an hour to see if it holds vacuum, then run the vacuum some more (seeing as how I have no vacuum gauge). Always disconnect pump with valve when turning it off to avoid sucking pump oil into system.
e. Discharge first can into suction line. Measure weight loss to determine amount charged so far. Run compressor. Close can tap, then close suction line on manifold gauge. The yellow manifold line should be empty.
f. Switch refrigerant cans; do not puncture new can yet. Run vacuum pump for enough time to evacuate the yellow line. Then open and discharge the next can as before.
g. When total dispensed refrigerant reaches the middle part of the spec, close the can tap. Close high side coupler. Open high/low side valves on manifold. Allow compressor to suck in remaining refrigerant in the manifold lines. Done!!
h. A question: The above procedure assumes that most refrigerant can be sucked into the system by the compressor, such that I do not need to worry about refrigerant losses in the manifold lines. Is this a correct assumption? Or is there some way to estimate how much refrigerant will be lost in the manifold lines?

Regarding any "take to to a shop" naysayers, which seems especially common in regards to AC repair: if I listened to these people, I wouldn't even know how to replace my own engine oil. The tools are expensive but there will surely be more times I will use them. I buy older cars and I hope these tools would last for years given the light use... Am I on the right track? Suggestions on what you might do differently? Are the tools/parts I have mentioned good choices? Sorry for the long post but unlike some people I'm hoping to be doing my research if I actually attempt this!

Cussboy on Tue July 16, 2013 1:31 PM User is offline

I think that you are doing "too much" for a repair caused by a bad flexible AC line (hose) for a vehicle of this vintage. I don't think I'd bother with stuff like compressor seals, expansion valve, clutch bearing.


Quote
Originally posted by: PredatorCoder
Open up all valves: evacuate air from manifold and car for 1 hour. Test for an hour to see if it holds vacuum, then run the vacuum some more (seeing as how I have no vacuum gauge).

The refrigeration manifold you obtain will have a vacuum gauge as part of the low pressure gauge.

Leggie on Tue July 16, 2013 1:39 PM User is offline

The things you are saying here makes it quite clear that you have never done it. The parts that aren't broken now, I'm afraid you will break it after this. Most of what you're wanting to do is totally unnecessary.

The flush would be necessary if your compressor already broke, obliterated and bits of metals are everywhere. If you're using the existing compressor, the damage from whatever debris is already done anyhow.

Replace the leaking hose and valve cores. Valve cores don't cost much and they're quite often susceptible to leaks and they can't be replaced all too conveniently after its charged, so do it now. Use new o-rings at joints you must break to replace the affected hose.

Vacuum and check for tightness. Make sure no rise in pressure after 15-20 minutes.

If the system has been flat for a while, park outside, bake it as hot as you could in the sun and vacuum for a few hours with your existing dryer to get the bulk of the moisture. This reduces the amount of moisture your new dryer has to remove.

Install new dryer, vacuum again and charge with something that has leak dye. If it leaks again, you go back and look with blacklight.

PredatorCoder on Tue July 16, 2013 10:22 PM User is offline

Thanks for the feedback. Keep in mind I'm looking to do opportunistic preventive maintenance here in addition to the minimum work for a repair... (I'm the kind of guy who usually changes every seal, idler pulley, water pump, and belt, when doing a timing belt job... And then checks valve clearances while I'm in there.) Responses inline below...

Quote
Originally posted by: Cussboy
I think that you are doing "too much" for a repair caused by a bad flexible AC line (hose) for a vehicle of this vintage. I don't think I'd bother with stuff like compressor seals, expansion valve, clutch bearing.

Are these other parts likely good for many years to come? I would like to not have to touch this system for a long while... I'm hoping I picked off the likeliest points of failure in the future...

Quote
The refrigeration manifold you obtain will have a vacuum gauge as part of the low pressure gauge.

Regarding vacuum gauges... this boiling point chart: boiling point chart shows that there is a big difference between 29" Hg and 30" Hg. The average manifold gauge doesn't seem like it has the resolution to really tell 28.8" and 29.5" apart, and even if you think you have it figured out, is there additional error? Your 100 micron deep vacuum pump might only be achieving 10000 microns and you wouldn't know. That's why I raised the subject...

Quote
Originally posted by: Leggie
The things you are saying here makes it quite clear that you have never done it. The parts that aren't broken now, I'm afraid you will break it after this. Most of what you're wanting to do is totally unnecessary.

Right. I stated I was new at the beginning of the message. There is always some risk of breaking something when working on any machine especially when it's the first time; I'm willing to take it. I have to start somewhere. However, I have found that careful research and attention to detail yields better results. Which is why I ask these questions; I am curious, what will I likely break that is not broken now - was there something I overlooked?

(I optimistically like to think I've learned enough beyond the point of the novices who will break their A/Cs when touching it for the most basic of tasks...)

My idea is to have a system that will continue to function for years. Even though the car is "old", I have no intention of dumping it short of a car wreck. I am not interested in fixing it every summer, which I fear is what it will turn into if I fix leaks piecemeal and it keeps leaking incessantly. (E.g. fix one leak somewhere, and another leak soon starts....) In general, I find that rubber/plastic hoses & seals on this car have become very stiff & brittle and at high risk of leaking, thus the seemingly-lengthy list of proposed replacements... Perhaps some parts really are totally unnecessary; I erred on the side of caution. But, I assume most really are necessary if I want to keep the system going for much longer than just this one leak?

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The flush would be necessary if your compressor already broke, obliterated and bits of metals are everywhere. If you're using the existing compressor, the damage from whatever debris is already done anyhow.

Yes, this is the obvious, most common reason for flushing. My reasoning was a little different; if I don't flush, this raises some new questions:

1. It appears that a good amount of oil has leaked out at the fitting. How much leaked out? (I.e. how much do I need to add?) Keeping in mind that the history of the car before I bought it is completely unknown to us.
2. The Hecat flushing paper suggests that the oil will break down as part of normal wear & tear: it loses its lubricity, and gradually absorbs tiny debris generated as normal wear & tear. PAG oil manufacturers only advertise "lifetime of the compressor" (which I hope to extend by restoring the rest of the system to good condition). This seems like logical common sense: after all, we change our other fluids far more often than we do the A/C oil... But maybe my concerns are unjustified; what is the actual lifetime of PAG oil in a system? How many years/miles is typical before the oil has degraded to a point that it is no longer safe to use in an A/C system?
3. Continuing question #2 above, will the new receiver/drier clean up the old oil? I would imagine it helps but I have difficulty imagining it will restore the oil to almost-new condition... (After all, we replace engine oil even after we replace oil filters...)

If there is significant life left in the oil and a good estimate of the remaining oil can be ascertained such that the proper amount can be added, then I would agree flushing is not necessary. But I am not sure of the answer to either of these questions.

(And ignoring the question of whether the vehicle sitting for a few weeks with no positive refrigerant pressure and a leaky hose has left the oil too saturated with moisture from the humid climate I live in.... another unknown.)

Quote
Replace the leaking hose and valve cores. Valve cores don't cost much and they're quite often susceptible to leaks and they can't be replaced all too conveniently after its charged, so do it now. Use new o-rings at joints you must break to replace the affected hose.

But my valve cores aren't leaking, so why bother replacing them?

mk378 on Tue July 16, 2013 11:04 PM User is offline

Has it been sitting with zero pressure? As long as you keep some pressure that generally avoids water contamination. PAG oil doesn't technically go bad in a closed system, but it can be contaminated.

Small amounts of spilled oil make a big mess. The amount that comes out of a typical leak is miniscule. The problem with trying to change or add oil is that having too much oil is bad. The only way to know how much you really have would be to dismantle the whole system and flush it out then install new oil.

I agree with the others, replace hose, new drier with one oz oil to replace that trapped in the old drier, evacuate and recharge.

HECAT on Wed July 17, 2013 12:44 PM User is offline

I am glad you are doing your research and asking questions here. I think the shops recommendation to replace the hose, vacuum, and recharge was spot on given the age and mileage of the car. The very thorough process you are contemplating is good, but it would cost thousands of dollars to have a shop do such a near complete system replacement/overhaul.

I would not bother with seals, bearings, etc. on the old compressor; assuming it is a high mileage piece. Save yourself some headaches and time and just replace the entire (tired) compressor assembly. Have you ever reworked the heads on a old tired engine? The rings often cannot handle the fresh top end and the increased pressure placed upon them, and they fail.

I would replace the compressor, line sets, TXV, and filter/dryer. Flush the heat exchangers (evap and condenser) until you are 100% sure they are void of oils and solvents. How you flush and with what you flush is your call, just be 100% sure, no oil, no solvents remain.

Install all your new pieces, a fresh load of oil, vacuum (leak check) and recharge. A micron gauge is nice to see exactly where you are, but a good vacuum for 1 hr, with a vacuum decay test for another 1 hr will work.

IMHO... that's how I would do it.

-------------------------



HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

iceman2555 on Wed July 17, 2013 5:36 PM User is offlineView users profile

Total agreement with HECAT....see Karl....we do agree on some issues.

Taking short cuts is a direct path to premature component failure. The question of lubricant amount is critical. How do you know how much lube is in the system...how much leaked out....the only way to know for sure is to clean the system and start over with the correct amount and type. Flushing is one of the most overlooked aspects of an AC repair. Yet this one issue is a major contributor to lack of performance in a repaired system.

Some of the repairs are a bit superfluous, however, with the mileage and your desire to maintain the vehicle until the wheels truly fall off.....go for it.

Most of the OE (Honda included) do not recommend flushing the system for repairs....however, they do state that if the part is contaminated....replace the part. An undercharged (leaking) system can contribute to debris formulations within the system....typically in the condenser inlet....and if the system is leaking...and low pressures go below 14-15 psi the system will ingest air....the moisture contaminates the lubricant....and thusly the entire system could be contaminated.

OE's install a compressor on a vehicle and it will operate for many years and miles....the average life of a aftermarket compressor installation is less than one year.....but then the OE system was clean....lubricated properly....charged properly...and the engine cooling system was fully operational.....

Take the time....do it correctly....and in most cases the job will be completed in one attempt......damn...don'tja just love it.....

The problem faced is charging the system...the method attempted may not complete charge the system....and thus can affect lubricant migration.....an easier method would be to charged the system and then equalize the manifold/hose assembly.

Good luck...thanks for the detailed post....HECAT and I enjoyed reading it.

An old adage or maybe a new adage....when repairing a system....if refrigerant touches it...either needs to be clean or new.....

-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

PredatorCoder on Thu July 18, 2013 2:04 AM User is offline

Quote
Originally posted by: mk378
Has it been sitting with zero pressure? As long as you keep some pressure that generally avoids water contamination. PAG oil doesn't technically go bad in a closed system, but it can be contaminated.

Quite possibly; I haven't bought the gauges yet to check, but my directions were to recover the refrigerant. If they actually did that, I would expect there to be no pressure or a vacuum when I left there... Furthermore, they left the caps off the service ports, the hose leaks, and the car's been driven a decent amount since then... I would not be shocked to find zero pressure when I finally look at it.

Quote
Originally posted by: HECAT
I am glad you are doing your research and asking questions here. I think the shops recommendation to replace the hose, vacuum, and recharge was spot on given the age and mileage of the car. The very thorough process you are contemplating is good, but it would cost thousands of dollars to have a shop do such a near complete system replacement/overhaul.

Oh, probably so, if I wasn't planning on keeping the car much longer ("given the age and mileage"). But I otherwise like my car well enough as it is. I don't doubt you are right about shop labor costs, thus the reason I want to try it myself.

Quote
I would not bother with seals, bearings, etc. on the old compressor; assuming it is a high mileage piece. Save yourself some headaches and time and just replace the entire (tired) compressor assembly. Have you ever reworked the heads on a old tired engine? The rings often cannot handle the fresh top end and the increased pressure placed upon them, and they fail.

Sounds familiar! But I did my research and was careful to replace the old rings/bearings and successfully averted that disaster.

Of course, compressors != engines, what are the typical failure points other than seals I would tend to see on a Denso 10PA17C compressor that old? And likelihood? If there's a real risk of problems then you're right, I'd be better off replacing it; I'm just interested in knowing the why - the other wear items besides the seals in a typical compressor and their typical lifetimes. If the risk is pretty low I'll try the $30 reseal, but if I had to spend another $100 in parts (if they can even be obtained) just to really do it right, then it is pointless and I should not mess with it.

CenturyAutoAir posted a couple nice videos on YouTube showing a tear-down/resealing of a 10PA17C; looks pretty simple though it will take me a little longer than the 10 minutes it took him! That's how I got the idea to just reseal it. My only disagreement with that video was the use of mineral oil on the o-rings.... which is not R-134a compatible... better to use Nylog Blue I think...

Any recommendations on decent remanufactured brands out there? Or better to not bother and just buy new; again, recommended brands? (Sadly, the forum sponsor does not list who makes their compressors... I would imagine they are good, but I like knowing who made it when buying major parts... hint hint....) I see a Denso unit on RockAuto which I assume is good since they are the OEM, not much clue on the rest...

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I would replace the compressor, line sets, TXV, and filter/dryer. Flush the heat exchangers (evap and condenser) until you are 100% sure they are void of oils and solvents. How you flush and with what you flush is your call, just be 100% sure, no oil, no solvents remain.

The condensor is parallel flow; not sure about evaporator. I understand in the end it's my (inexperienced) call, but I'm fishing for flush advice as I haven't tried and compared every type of flush product on the market.

For example, Four Seasons, requires an approved flushing method for warranty. I would tend to think anything that a compressor manufacturer approves for warranty probably works. Nonapproved methods include most of the obvious flushing pitfalls of DIYers (oil, alcohol, etc... lol) and also closed-loop R134a flush as done by RRR machines. Approved methods include their relatively inexpensive flush gun with Dura Flush, and the HECAT systems with HECAT flush fluid.

Interestingly enough, the approved Four Seasons flush gun flyer says not to flush most modern condensors after a catastrophic failure, but also says the condensor can be flushed to remove only oil if the compressor has not failed. (The Dura Cool fluid seems to cost a crazy amount; I wonder if it would work just as well with the HECAT fluid...)

I also wonder how the 4s flush gun compares with the cheaper Robinair/Mastercool flush guns if run off shop air to deliver a constant, long air purge...??

The HECAT pulsator looks quite nice, but also costs a nice amount. I'm sure it's cheap for what it is compared to more expensive systems, but is it overkill for just flushing out the old oil? Can the 4s/MC/Robinair flush guns do this on parallel flow heat exchangers? (I assume the pulsator can handle that no problem...) I think it makes no sense to buy an RRR machine for working on just 2 or 3 cars at typical (new) RRR machine prices, while spending $80 on a basic, name-brand manifold makes lots of sense; just wondering if that tool is getting into the "little ridiculous" price range.

Quote
Originally posted by: iceman2555
Most of the OE (Honda included) do not recommend flushing the system for repairs....however, they do state that if the part is contaminated....replace the part. An undercharged (leaking) system can contribute to debris formulations within the system....typically in the condenser inlet....and if the system is leaking...and low pressures go below 14-15 psi the system will ingest air....the moisture contaminates the lubricant....and thusly the entire system could be contaminated.

There's a convincing argument to either flush/replace/do everything, or just do the minimum to fix the leak and charge the system and wait for the inevitable next failure... it seems there is a price vs. expected lifespan trade-off, depending on how long you wish to keep the vehicle...

Quote
the average life of a aftermarket compressor installation is less than one year.....

Really? Wow.... how can they afford to offer 12 month warranties...? Or I guess most people aren't even following the warranty requirements and then getting denied? (new receiver/tx valve, full flush)

Judging from other messages I've seen you write, I'm guessing you look at failed compressors for a company I have not yet been able to ascertain...

Quote
Take the time....do it correctly....and in most cases the job will be completed in one attempt......damn...don'tja just love it.....

My words to any business/technician working on anything of mine that is taking longer than they expected: "Take your time, just make sure it's done right!"

Quote
The problem faced is charging the system...the method attempted may not complete charge the system....and thus can affect lubricant migration.....an easier method would be to charged the system and then equalize the manifold/hose assembly.

Can you elaborate a bit on what you mean by "equalize the manifold/hose assembly"? This sounds like step 3g in my original post: close high-side coupler; open high/low valves on manifold; [leave low side open]. But then you say the method may result in undercharge so I'm wondering where I went wrong here. (confused)

Upon further thought after rereading my question in 3h, perhaps it would be best to come up with an actual estimation of the refrigerant stored in manifold/charge hoses by using ideal gas law formula (PV = nRT):
1. Pressure is trivially read from the gauge. If adequate time is given for temperatures to equalize, ambient temperature can be used. Molar mass of R-134a: 102.03 g/mol.
2. One unknown is the volume of the manifold and charge hoses. As an initial calibration step after evacuation, the R-134a couplers can be closed and then refrigerant can be charged into the manifold only, with valves set exactly as how they would be in step 3g. The change in weight indicates the mass of refrigerant that cannot be weighed by the scale. But we know that this "lost" refrigerant is just stored in the unweighed manifold volume. From this, we can calculate the manifold volume that is not weighed by the scale. At this point, it would be best to avoid disturbing the arrangement of tools for as long as this volume calibration value is needed. (Some refrigerant in the manifold is still being weighed, such as in the section of hose closest to the can, so it should not be counted in the unweighed manifold volume.)
3. Once we reach any step in the charging process that involves losing refrigerant stored in the manifold, it is necessary to determine how much refrigerant will be lost. This is trivially simple to determine with the ideal gas law, now that we have some idea of what the volume of the manifold was. If the value is great enough such that the system is undercharged, then add more refrigerant until this is no longer the case.

I guess the automated RRR machines figure out all that calculation for you (right??). But unless I went wrong somewhere in my calculations, it seems like that would be a reasonable way to find out the actual value. 10 minutes spent making up an Excel spreadsheet in advance should help with the math when actually working on the car, to reduce the chance of an error.

Quote
Good luck...thanks for the detailed post....HECAT and I enjoyed reading it.

Thanks - glad you enjoyed it. Maybe if I feel extra ambitious later I can take a few pictures and write it up. Most write-ups seem to go along the lines of "vacuum, then add a couple cans of R-134a and call it good." When the published tolerance of the system in the service manual is +/- 0.8 oz, there is no way you can do that by just dumping cans in without careful weighing...

94RX-7 on Thu July 18, 2013 12:53 PM User is offline

Quote
Originally posted by: PredatorCoder
My only disagreement with that video was the use of mineral oil on the o-rings.... which is not R-134a compatible

Mineral oil and R-134a can coexist happily together without adverse chemical reactions. It is fine as an assembly lubricant.

When you say "not compatible" what you're actually referring to is the fact that R-134a won't circulate mineral oil through the system very well (if at all) so it can't be relied upon to properly lubricate a running R-134a system.

HECAT on Thu July 18, 2013 1:17 PM User is offline

With no disrespect to 4S or any other vendor that sell the little 1 qt u-fill flush gun or a/c flush in an aerosol can; lets also include quarts of flush solvents that say "pour in and blow out". All of these methods produce a dismal (ineffective) flow rate, do not use an adequate volume for the circuit size, and rely on constant pressure. The methods are truly bound by the "path of least resistance" (fluid physics principal) rule and will flow around and over the materials you want to remove in parallel path components. These methods make the "you can't flush condensers" statements true. But people want a short cut and they want it cheap; so these vendors sell a lot of this product regardless of this little technicality regarding their piss poor performance. At least 4S recognizes this limitation as you pointed out.

We have for many years produced effective flushing tools for the professional repair trade, but these cart units range from $3,500 to $10,000. We have proven the process and have automotive, fleet, and aviation OE approvals. The owner of this site asked us (and we were already looking at it) to see if we could bring the necessary performance to a DIY type tool. The Pulsator Flush Gun brings a much higher flow rate, using 1 gallon of solvent, and includes our patented kinetic energy pulse. This high flow rate in combination with the pulse defeats the rules to "path of least resistance, scrubs into corners, crevices, and parallel paths; and keeps the contaminants suspended in the agitation action of the flush so it can be carried out.

So there is the difference. Do you want to flush it, or do you want to "poof" it?



-------------------------



HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 


Edited: Thu July 18, 2013 at 7:10 PM by HECAT

Leggie on Wed July 24, 2013 7:38 AM User is offline

Simply put, hecat works like when air gets entrapped in your water line and all that nasty stuff comes out. When pockets of air get compressor and released, it acts like a spring and the release of energy loosens debris.

Another issue is that due to environmental impacts, modern flush solvents are much less volatile and if you have any amounts of stagnation in your system, it will get sealed into the system and cause issues. This was not an issue with CFC-12 or HCFC-141b, both of which are banned for this purpose.

iceman2555 on Wed July 24, 2013 8:54 PM User is offlineView users profile

Equalization is as described. Most do not take this step and this should allow the system to be more fully charged.....the best and only method to insure proper charge is the use of a machine or other type of weight measurement device.

Yes, I do work for a compressor manufacturer and part of my responsibilities are failure analysis of compressors and other AC components. I have seen all types of failures....experienced all types of flush chemicals...(if not removed properly they leave residues). Evacuation, does not remove the majority of flush chemicals....even those that advertise 'fast evaporating'. I also work as part of a nationwide technical call in. That is one of the most interesting aspects.....should write a book about the calls that come in.

Good luck with your repair. Doing it completely and properly greatly reduces the chance of a component failure. Pls keep in mind...after all this work...to insure that the system is totally recharged.

-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

Dougflas on Thu July 25, 2013 7:55 AM User is offline

I saw someone suggested pulling a vacuum and setting the vehicle in the sun to "bake". Not a bad idea but.....You can not then open the sysem up and change the drier. You must put some positive pressure in the system or moisture and air will be sucked into the sytem. At least break the sysem with N2 or R134 just to get out of the vacuum range.

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