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!
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.
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.
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...
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.
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.
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.
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?
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.
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.
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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