Air­con conned

Motor Equipment News - - DIAGNOSTICS -

This ar­ti­cle is a true de­scrip­tion of an AECS tech­ni­cal help desk prob­lem and how it was solved. By Paul Cor­bett, A/C trainer.

Prob­lem we ran into

Most re­frig­er­ants cur­rently used in New Zealand are clas­si­fied as com­pressed gases un­der the Haz­ardous Sub­stances (Com­pressed Gases) Reg­u­la­tions 2004 (Com­pressed Gas Reg­u­la­tions).

Un­der the cur­rent HSNO Act (Haz­ardous Sub­stances and New Or­gan­isms), any­body han­dling or re­cov­er­ing com­pressed gasses which in­cludes R134a must have had suit­able train­ing and hold a Filler and/or Han­dler Cer­tifi­cate.

The rea­sons for this are sim­ply put twofold: The re­lease of re­frig­er­ant into our en­vi­ron­ment MUST stop. Pump­ing re­frig­er­ant into a bot­tle or sys­tem can cause ma­jor harm to any­body in the vicin­ity when me­chan­i­cal fail­ure oc­curs. Both are pre­ventable, but any is­sues will not be recog­nised by un­trained per­son­nel. Please think about the health and safety is­sues your shop would face in case of an ac­ci­dent when you have un­trained per­son­nel at the con­trols!

To more or less en­force the train­ing re­quire­ment on in­dus­try, on Jan­uary 1 2015, it be­came a re­quire­ment for anyone wish­ing to pur­chase re­frig­er­ant gas to present a Fillers and/ or Han­dlers li­cence. The de­ci­sion to re­strict sales in this way is a vol­un­tary agree­ment made by rep­utable re­frig­er­ant sup­pli­ers to help en­sure safe prac­tice in re­frig­er­ant use within our in­dus­try.

It would ap­pear though, that nearly two years on it is still pos­si­ble for just about anyone to pur­chase R134a with­out any ques­tions be­ing asked and hardly any licences be­ing checked.

Laugh it off

It is quite ap­par­ent that there are sales-driven com­pa­nies within the au­to­mo­tive in­dus­try that do not have best prac­tices at heart. Th­ese com­pa­nies are sim­ply ig­nor­ing leg­is­la­tion and agree­ments be­tween those who are striv­ing to make our in­dus­try safer, cleaner and greener.

We all need to fo­cus on lift­ing the stan­dards of our in­dus­try in the eyes of the gen­eral pub­lic, else we soon end up hav­ing a very large throw away in­dus­try with no work for pro­fes­sional re­pair­ers any­more.

At AECS we de­liver air-con­di­tion­ing cour­ses reg­u­larly na­tion­wide through­out the year, and at­tend train­ing our­selves to stay at the very fore­front in terms of avail­able prod­ucts and tech­nol­ogy – and it is through our cour­ses that we of­ten get to hear the sto­ries of how read­ily avail­able re­frig­er­ant is – eas­ily be or­dered over the phone in just a few min­utes, no ques­tions asked, and sent via a courier to wher­ever you like.

Dur­ing th­ese sem­i­nars, we also get to hear about some of the many myths, and in some cases bla­tant lies, that are spread by ill-in­formed sup­pli­ers/ sales peo­ple in a quest to sell more of their own prod­ucts. This is not the cor­rect way to raise the pro­file of the au­to­mo­tive in­dus­try in NZ, and is not in­dica­tive of the vast ma­jor­ity of us. If we don’t at least try to self-reg­u­late, stronger more un­palat­able rules and re­stric­tions will inevitably fol­low.

If this is not cause for con­cern enough I feel duty bound to bring to your at­ten­tion some­thing that has been trou­bling us at AECS for sev­eral years now.

Stop stop-leak!

A/C ser­vic­ing is a thriv­ing part of the au­to­mo­tive sec­tor, but there now lurks a silent killer for A/C sys­tems and ser­vice equip­ment which we rec­om­mend be stopped firmly in its tracks at your work­shop door be­fore it wreaks havoc with not only your equip­ment but also your cus­tomers’ ve­hi­cles!

A/C “stop leak” is the generic name for this silent men­ace, and we have ex­pe­ri­enced first-hand what sort of dam­age this in­no­cently named sub­stance can do. Please un­der­stand we do not sin­gle out any brand of “stop leak”.

When a ve­hi­cle’s A/C sys­tem is not ser­viced of­ten enough (ser­vice is mois­ture, air, par­ti­cle re­moval and recharge), air and mois­ture are present in the sys­tem. Most ve­hi­cles need ser­vic­ing ev­ery 24 months.

So why is “stop leak” so bad? By its na­ture it is de­signed to re­act on con­tact with air or mois­ture to cre­ate what is at best a tem­po­rary re­pair to leak­ing A/C sys­tems.

So, what’s wrong with that? Put sim­ply, first it is be­cause of how stop leak al­ters the tech­ni­cal prop­er­ties of the var­i­ous seals within the A/C sys­tem in a quest to weaken/soften leak­ing seals.

The seals of­ten be­come overly soft, to the point of dis­tor­tion (cre­at­ing new leak­ages on the most in­ac­ces­si­ble spots), and se­cond, the way in which the stop leak changes state on con­tact with air or mois­ture.

The stop leak will ei­ther trans­form into crys­tals, or it trans­forms into a rub­bery sub­stance (of­ten tiny rub­ber balls) set­tling on valves and so­le­noids in the sys­tem. Both have the po­ten­tial to cause havoc in the A/C sys­tems on ve­hi­cles and in your A/C ser­vice equip­ment.

On top of that many stop leak can­is­ters con­tain re­frig­er­ant to keep the can pres­surised, and to as­sist in­jec­tion into the ve­hi­cle. The ex­tra re­frig­er­ant en­ter­ing the ve­hi­cle is un­metered (top up).

Kills equip­ment

Please re­alise that when you con­nect your A/C ser­vice equip­ment (or the stop leak can­is­ter) to a ve­hi­cle, the tiny amount of air trapped in the high or low pres­sure cou­pler is all that is needed to start the chem­i­cal re­ac­tion even be­fore the vac­uum pump can re­move the air.

We as distrib­u­tors of A/C equip­ment have ev­i­dence that this sub­stance has caused mas­sive fail­ures in sev­eral ma­jor brands of A/C ser­vice equip­ment – equip­ment which be­came so hor­ren­dously con­tam­i­nated that the ser­vice ma­chines were even­tu­ally writ­ten off. The cost of re­plac­ing the af­fected parts, com­bined with the time to clean the rest of the ma­chine to en­sure no stop leak re­mains is huge.

On this page are pic­tures we took of a con­tam­i­nated ma­chine’s in­side. Imag­ine what stop leak does to the in­side of the car’s A/C sys­tem when air is present in that sys­tem.

In­tro­duc­ing air in the car’s A/C sys­tem is as easy as hook­ing up an old fash­ioned gauge set, where the pres­sure gauges read, for ex­am­ple, zero Bar.

A /C top up

At a re­cent sem­i­nar, a trainee showed me what he had been us­ing on a reg­u­lar ba­sis to “top up” his cus­tomers’ cars dur­ing reg­u­lar ser­vices, as he had been con­vinced

by a sales per­son that it would be a great lit­tle earner for his business, and was even con­tacted by that sales per­son sev­eral times to be asked “why are you not or­der­ing lots more as so many peo­ple were now us­ing this amaz­ing prod­uct”. Call that a des­per­ate hard sell!

When top­ping up an A/C sys­tem it is im­pos­si­ble to know the to­tal amount of re­frig­er­ant in the sys­tem; for in­stance, some BMWs need the cor­rect charge +/-10g to get the best cool­ing ef­fect. The cool­ing ef­fect of the A/C sys­tem re­duces when the sys­tem is over OR un­der­charged.

Once I had tech­ni­cally ex­plained in the AECS A/C train­ing about the dan­gers of stop leak and top­ping up, the trainee agreed to stop us­ing the prod­uct and re­turn any he had left. Please note that dur­ing our train­ing we run up a rig un­der and over charged. Train­ing goes a long way!


A point of con­cern for him now is the fact that ev­ery car he has “topped up” is now in­fected with the dreaded stop leak, and he un­der­stand­ably does not want to put his A/C ser­vice equip­ment any­where near those ve­hi­cles he pre­vi­ously topped up.

What will his cus­tomers say if they take that ve­hi­cle to some­where that tests for the pres­ence os stop leak and then re­fuses to work of that car’s A/C as it is likely to fail and it poses a ma­jor risk to A/C ser­vice equip­ment?

What also is of con­cern, is that th­ese top-up bot­tles are be­ing sold to peo­ple with re­frig­er­ant fillers licences on a reg­u­lar ba­sis. Surely they should fall un­der the same reg­u­la­tion as ev­ery A/C ser­vice per­son. The con­tain­ers (13.6kg bot­tles) are ev­ery bit as harm­ful as the top up bot­tles. Some of them can hold up to 1kg of R134a.

Stop leak de­tec­tion kit

The dan­gers of the A/C stop leak have be­come such an is­sue that a few years ago an overseas man­u­fac­turer de­vel­oped a stop leak de­tec­tion kit. We have been sup­ply­ing th­ese de­tec­tion kits to the au­to­mo­tive trade for a few years now, and they con­tinue to be in high de­mand – it’s a sim­ple kit with purely me­chan­i­cal com­po­nents.

Sadly, for some work­shops th­ese kits have come too late. We have had to tell a few work­shops al­ready that their trusted A/C ser­vice ma­chine is be­yond rea­son­able re­pair. It’s not usu­ally a happy phone call! We at AECS use this test­ing kit for test­ing BE­FORE we ser­vice A/C ma­chines.

Top up with a mix?

There are sev­eral man­u­fac­tur­ers and sup­pli­ers of top up prod­ucts, and as you can see in the pic­tures, they don’t even try to hide the pres­ence of the harm­ful stop leak. Through ei­ther lack of train­ing or pure ig­no­rance the sup­pli­ers seem happy to con­tinue to sell th­ese prod­ucts to the trade.

You may have been of­fered or have seen for sale A/C top-up or auto air con­di­tion­ing recharge prod­ucts which upon closer in­spec­tion you will soon dis­cover con­tains R134a gas, the dreaded stop leak, some ran­dom uni­ver­sal PAG oil and oc­ca­sion­ally some tracer dye.

We from AECS ad­vice you to avoid th­ese prod­ucts and ser­vice the A/C sys­tem ac­cord­ing to pro­fes­sional stan­dards.


Work with high stan­dards, that AL­WAYS pays in the end. Skill up and choose top level equip­ment. Our train­ing is avail­able through­out NZ and easy ac­ces­si­ble. Be­sides be­ing very good value and high on tech­ni­cal con­tent, it is also FUN!

When choos­ing equip­ment, sup­port and train­ing be sure you pick a sup­plier who not only thor­oughly un­der­stands the equip­ment they are sup­ply­ing but can train you cor­rectly and sup­port you into the fu­ture with a qual­ity ser­vice you can rely on.

Stop leak de­tec­tion kit

So­lid­i­fied stop leak we found in many pipes and ori­fices in­side the A/C ser­vice equip­ment.

Rub­ber seal in the valve had swollen to +/- 5x its orig­i­nal thick­ness.

Valve with swollen rub­ber seal.

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