Quick Taurus Fix: 134a A/C Recharge

It seems to me it was­n’t all that long ago that any­thing to do with an A/C sys­tem was heav­i­ly reg­u­lat­ed and out of reach for the home shop repair­man.  I’m not even sure when this changed.  It obvi­ous­ly has some­thing to do with the fact that the new “134a” gas is no longer reg­u­lat­ed (ie: not thought to cause o‑zone deple­tion), but it also destroys the mys­tique of A/C units — the very fact that you can repair them yourself.

Chris­tine came home from work Fri­day com­plain­ing that the A/C cut out on the Tau­rus that morn­ing.  Reg­u­lar read­ers will remem­ber that we just fin­ished fix­ing the starter in the Tau­rus and more than that, it was laid up for near­ly a month while we fig­ured that one out… so Chris­tine was rather despon­dent about it.  We’re in the mid­dle of a heat wave here in South­ern Ontario and the auto cli­mate sys­tem in the Tau­rus isn’t exact­ly friend­ly to use with­out it’s abil­i­ty to cool.  In fact, the defrost func­tion often gets it very wrong under these con­di­tions as it expects to use the A/C sys­tem to dry the air for defrost duty.

I spent some time on the inter­tubes (of course).  The Tau­rus Car Club of Amer­i­ca is a favorite spot.  I also accessed my all­datadiy sub­scrip­tion.  With the car run­ning I could hear the com­pres­sor cut­ting in and out repeat­ed­ly and the air from the vents was “some­what” cold­er than the ambi­ent.  From this research, I con­clud­ed that the car was low but not out of A/C gas.

Red Tek A/C Recharge Kit Guage

Red Tek A/C Recharge Kit Guage

Enter the Red-Tek A/C recharge kit.  The pic­ture to the right is the guage that comes with the kit which includes the guage and two 6 oz cans of 134a with dye.  The “dye” allows one to spot leaks and it oth­er­wise appar­ent­ly harm­less.  Here in Cana­da, Part­Source and Cana­di­an Tire are both sell­ing the kit for $55 and the refills (if you need more) for $17.  They also sell two dif­fer­ent leak plug­ging prod­ucts (at least one of which was warned against for most appli­ca­tions in the online forums) and an oil boost­ing prod­uct.  You can also get the 134a with­out the dye if you pre­fer.  I’ll add the note here that the Sears Crafts­man Red Cab­i­net was a gift that I real­ly appre­ci­ate from my late father-in-law Gary Enright.

The kit is fair­ly sim­ple to use.  You’ll have two con­nec­tions under the hood the “high side” (on which the con­nec­tor will not fit) and the “low side.”  On the Tau­rus, the low side is almost hid­den near the fire­wall on the pas­sen­ger side.  The “high side” con­nec­tor, on the oth­er hand, sticks up con­ve­nient­ly right in front of the coolant reser­voir.  Con­nect a can of 134a to the end with the but­ter­fly fit­ting.  With this con­nect­ed, con­nect the quick-con­nect side to your “low side” port.

In my case, at this point (engine, off) there was 30PSI read­ing on the guage — mean­ing that the sys­tem had not lost all of it’s gas (this is a good thing).  The pack­age rec­om­mends a start­ing charge, but in my case, releas­ing gas from the can imme­di­ate­ly shot the pres­sure up to 40 psi where the tar­get range is appar­ent­ly 30 to 38 psi.  I had Chris­tine start the car and put the A/C on “max” (the next step in the instruc­tions) and the pres­sure dropped rel­a­tive­ly imme­di­ate­ly to around 10 psi (and I could hear the com­pres­sor cut­ting out).  I opened the can fur­ther and the pres­sure sta­bi­lized just above 30 psi until the can was emp­ty.  I think you could let the gas rush in faster, but I was being cautious.

The can gets cold as the gas exits and you can tell when the can is emp­ty as it gets warm.  In my case, we were at 25 psi (the sys­tem was cool­ing) after the first can, so I elect­ed to add a sec­ond can.  It seemed to state that you dis­con­nect from the car’s “low port” first before remov­ing the can — I hon­est­ly don’t know what sort of check valves the thing has and the direc­tions were light on the top­ic.  For safe­ty, I dis­con­nect­ed from the car, removed the old can, insert­ed the new and resumed fill­ing.  I also tried shut­ting the car off — but this result­ed in the “low side” pres­sure ris­ing dra­mat­i­cal­ly — over 70 psi and I rea­soned that remov­ing the “low side” fit­ting while the com­pres­sor was run­ning (at 20 or 30 psi) was much prefer­able (less lost gas) than at 70 psi or more with it stopped.  There may be a point where this goes back down if you wait long enough, but I did not.

In all, 2 cans (6 oz each) brought the low side pres­sure back to 34 psi — right in the mid­dle of “good” and the cool air was  flow­ing.  All­Da­ta says that my capac­i­ty is 34 oz, so it would seem that we pos­si­bly lost 1/3 of the total gas.  If this is “since we bought the car” … it’s def­i­nite­ly accept­able.  If this is recent­ly, then there will like­ly be anoth­er post on this subject.

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9 Responses to Quick Taurus Fix: 134a A/C Recharge

  1. DaD says:

    You might now vol­un­teer to test the oth­er fam­i­ly A/C sys­tems. Espe­cial­ly Rebec­ca­’s, which is not work­ing, if I remem­ber cor­rect­ly. Ours gets cold just fine, but the com­pres­sor cuts in and out fre­quent­ly — not sure if that is some­thing we can fix.

    • dgilbert says:

      The unit does­n’t so much “test” as fill. In Rebec­ca­’s case, I already looked at her prob­lem. Her com­pres­sor is seized. When I was going to bor­row her car (the day before you helped with the starters), when I got into it and start­ed it, it was mak­ing strange nois­es — basi­cal­ly the belt was stalling on the com­pres­sor wheel every time the clutch engaged). Since her sys­tem has been emp­ty for so long (obvi­ous­ly) it would at least require repair and then evac­u­a­tion. Now… I’ve read some­one say they made an eval­u­a­tor using and old fridge com­pres­sor, I don’t know if we’re up for that. The down­side of not mak­ing an evac­u­a­tor is that acid devel­ops in the sys­tem and quick­ly destroys it. So Rebec­ca­’s repair is at least requir­ing a new com­pres­sor — and what­ev­er pipe work that requires (I haven’t ful­ly read up on how those fit­tings work, but they are high pres­sure — 50 to 100 psi eas­i­ly), evac­u­a­tion and then charg­ing … of which we know about charg­ing. I had already told Rebec­ca that fix­ing her com­pres­sor might require a pro­fes­sion­al. I also told her that it was vital that she not turn on her A/C … since break­ing the belt or the A/C pul­ley would man­date replac­ing the com­pres­sor — and that might not be convenient.

      Your case, how­ev­er, is prob­a­bly large­ly like mine. Low gas pres­sure caus­es fre­quent cycling of the com­pres­sor (there is a low pres­sure cut­off switch on the low side line). Iron­i­cal­ly, it prob­a­bly runs fine-ish in hot weath­er and does the rapid cut out as it gets cold­er. Any­ways… you’d need to stop by part­source and pick up the red tek can ($16.99) and then be in the same place as my guage and hose. One can is prob­a­bly enough if you’re still cooling.

      • DaD says:

        I should try that, because my a/c has been short-cycling almost since we bought the car. But even on a day when the out­side tem­per­a­ture read *40 degrees* (and I could believe it) the air com­ing from the vents was accept­ably cool. But at least for this sea­son I haven’t been able to pro­duce the ice-cream-headache temperature.

  2. DaD says:

    Can you look up in your all­datadiy about mas­ter cylin­der in the Sube? Mine (at least I think it’s the M/C) is behav­ing bad­ly — espe­cial­ly in near-pan­ic stops (which hap­pen often enough on the 401).

    • dgilbert says:

      What is the symptom?

      • DaD says:

        Real­ly soft brak­ing on heavy pres­sure. Inabil­i­ty to lock the wheels, even on a wet road. Guy at the shop rec­om­mends a com­plete brake-flu­id flush, which we can do when we do the rear brakes.

        • dgilbert says:

          Yeah… that might be air or con­t­a­m­i­na­tion in the sys­tem — I’m not sure it would be some­thing wrong with the mas­ter cylin­der, though. Air and Water are the most like­ly cul­prits — or by rec­om­mend­ing a flush, that’s what the mechan­ic is say­ing. Since the mas­ter cylin­der is just a pis­ton, I imag­ine it’s fail­ure modes are rather sim­ple … like leak­ing. This could be, though, some­thing to do with the brake boost­er or some­such. It may be pos­si­ble that with­out boost you can’t devel­op the required pres­sure to lock things up.

  3. Rick says:

    Red-Tek A/C recharge kit!!!!! Did you know that this prod­uct is noth­ing but propane? How nice to be cre­at­ing a bomb with your a/c sys­tem. Propane can act as a very good replace­ment refrig­er­ant, how­ev­er that said, it is very flam­ma­ble. Try cor­rect­ing your prob­lem with the cor­rect replace­ment refrig­er­ant that is non-flammable.

    • dgilbert says:

      You’re the first (seri­ous­ly) to post that. But being con­cerned, I did some research. And note that I’m not an inter­net new­bie… I pushed fair­ly deep. If you have some good arti­cles you’d like me to read, I’d appre­ci­ate the post.

      Most of what I’ve read so far acknowl­edges that R12a is flam­ma­ble, but less-so than (say) a rup­tured fuel line. Gaso­line has an incred­i­bly low flash­point and will ignite on your exhaust man­i­folds. R12a has a flash­point (at ide­al mix­ture) of about 1584 (from mem­o­ry). A diesel truck with a stonk­ing 2+ atmos­phere boost pulling up a hill at WOT (Wide open throt­tle) might get it’s exhaust man­i­fold to 1584, but that kind of tem­per­a­ture will quick­ly destroy your cat­alyt­ic con­vert­er … so you can almost guar­an­tee that you won’t find that tem­per­a­ture in the engine.

      In terms of flam­ma­bil­i­ty, sev­er­al posts point out that in a severe leak, the com­pres­sor oil is more flam­ma­ble than the gas. Note that the oil is the same for both R12a and R134a.

      I’ve been known to say that if all vehi­cles were diesel and some­one came up with gaso­line, there is absolute­ly no way it would be approved for sale today. Gaso­line is amaz­ing­ly dan­ger­ous. Your vehi­cle is car­ry­ing around 30 to 50 kq of gaso­line when full. With Red-Tek, we’re talk­ing about 200 to 500 grams of a gas that’s rather hard to light. I’m not say­ing that you can’t hurt your­self, I’m just say­ing that gaso­line cars are fair­ly dan­ger­ous and prone to engine fires and explo­sions all by themselves.

      I also came across sev­er­al arti­cles stat­ing that R12a was in use around the world (more so in oth­er coun­tries than Cana­da and the US) and that nobody could come up with an inci­dent of it injur­ing some­one save a “pro­fes­sor” who emp­tied a can into the inte­ri­or of a vehi­cle and lit a match (not exceed­ing­ly bright).

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