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Air Conditioning recharge


Guest 63riviera

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Guest 63riviera

The last owner of my '73 Riv had the A/C system completely converted to the newer environmentally friendly refrigerant(R-45?)last year.

The systems seems to work well, except yesterday i was driving,and did get warm,so tried the AIR and MAX COOL. They used to be ice-cold. Now it feels like vent air, although when I select even there is a change in temperature between the two.

id there an inexpensive to re-charge the A/C system? I don't have all the pressure gauge tools and such

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To do it right, you'll need to have the necessary recycling machine AND know exactly what refrigerant was put into the system. The last part is a key issue as no shop wants their existing cannister of either R-12 or R-134a contaminated with some unknown items (which might cost the customer the price of a new cannister to replace it).

From the ackits.com forums, the general rule of thumb was to start with a R-134a charge of 80% of the R-12 spec and then slowly increase it until the pressures got into about the same relationship as they would have with R-12 at the full spec charge level. It's possible that when you're through, you'll end up at about the 90% of R-12 charge level with R-134a.

In any event, with what's not in there, you'll need to do a full evacuation to get all of the moisture out of the system (as there's less charge in there now than used to be there last time you used the a/c). But you'll also need to find why the refrigerant leaked out and/or why the compressor might not be running.

Just some thoughts . . .

NTX5467

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There is no such thing as R45 Refrigerant. Usually when a system is converted they will change the service fittings which are specific to the type of refrigerant to help avoid accidental mixing. A shop may be able to tell if its 134A (the most common R12 conversion refrigerant), by the fittings, however the fitting alone wouldn't be good enough for me. If you are not 100% sure, try contacting the owner. Assuming or guessing whats in there is out of the question. You need to know for sure.

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One possible leak source is the 0-rings in the lines. When my Regal changed from R-12 to R-=134, a similar leak to what you described occured within a day or so. Seems the Regal had SAE dimension 0-rings, rubber, and the R-134 system needed metric, neoprene. The shop did the change, and the car has been running 7 years on that charge.

Dale

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Guest Riviera66

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The last owner of my '73 Riv had the A/C system completely converted to the newer environmentally friendly refrigerant(R-45?)last year. The systems seems to work well, except yesterday i was driving,and did get warm,so tried the AIR and MAX COOL. They used to be ice-cold. Now it feels like vent air, although when I select even there is a change in temperature between the two.</div></div>

I suspect R-134a is what you mean. Unfortunately, the R-134a 'conversions' that AC shops are so eager to push are a major disappointment for all our older systems with A-6 compressors. (And that's everything from the '70s and earlier at a minimum.) R-134a will work ok as a conversion in some newer cars... but not in the old ones. The systems will work ok to 'good' (for a while) except when it gets really hot and then they're useless. Add in the fact that older systems weren't built for R-134a's pressure curve and the fact that R-134a leaks out easier and you can see why so many are disappointed.

I tried R-134a in one of my cars and absolutely hated it... I went from a system that could frost the metal vents in the Mojave Desert to one that was only tolerably cool on a warm day. Your best bet is to find a good AC shop and get the conversion undone. Most of the replacement oil they put in on these conversions is backward compatible with R-12. You just need to have the remainder of the R-134a evacuated and get good refrigerant put in. Either return to R-12 or get a replacement refrigerant that works in the old systems like Freeze-12 or Duracool et al. As has been mentioned, most AC shops don't want to deal with anything but R-134a now... and the few that do anything else will only want to support R-12 also. So the replacement refrigerants, Freeze-12, Duracool, et al that work really well won't be suggested. Given the fact that R-134a's price has jumped significantly, R-12 doesn't seem all that expensive like it used to.

Darwin Falk

1966-70 ROA Technical Advisor

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  • 9 years later...
Guest sheldonsmith

I recharged my system this year with a small can of R134a, separate charging hose, and the interdynamics test kit (cheap pressure gauge & thermometer). At first you could tell no charge was going into the system, so I tipped the can upside-down.A/C repair isn't cheap and many don't attempt it due to EPA regs (which are widely misunderstood). The internet has a lot of A/C repair information, including EPA regs, which basically tell you that you can't vent a system but leaks are OK. A decent set of gauges can be had for $40 including hoses (Harbor Freight). Temporary fixes are ok, just understand you may need to do this again in days, weeks, or a year later.I also googled and find Heating Service Cypress and they resolve all my problem.
 
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It will be obvious if you have the 134 fittings on your car and it is notorious for poor performance especially at low RPM. Unless the VIR Valves were calibrated for the 134 it will be even worse if you lose some. I am working on mine and staying with R12. Nothing will compare when it comes down to it. You can buy a can of 134 that will have a gage built onto it. I forget the Brand. Try to add a little to the low side and see what happens. The gage should be adjustable for outside temp and will tell you when your good. I think about 40-50lbs on the low side. If you have a persistant leak you should get it taken care of. Good Luck.

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I see bubbles in the sight-glass on my '67 Riviera when the compressor is running, however, the A/C is blowing cold air.  I just acquired this car and it appears to still be running R-12 (no 134a conversion caps are present).  What are the chances that I will be able to take it somewhere and simply have the system checked for leaks and topped-off (with R-12)?

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4 hours ago, EmTee said:

I see bubbles in the sight-glass on my '67 Riviera when the compressor is running, however, the A/C is blowing cold air.  I just acquired this car and it appears to still be running R-12 (no 134a conversion caps are present).  What are the chances that I will be able to take it somewhere and simply have the system checked for leaks and topped-off (with R-12)?

 

It is hard to find a shop today that wants to mess with R-12.  Call around until you find one.  I buy the little cans of R-12 off of eBay and top up my system myself.  Not hard to do.  I add about a can a year.  Easy to over fill the system, though.  Add a small amount and test drive.  You can always add more later.  Overcharging is worse on cooling performance than undercharging.  Bubbles in the sight glass are not a bad thing.  Having the system chacked for leaks is a waste of time.  They all leak.  It's really just a matter of how fast.

 

 

 

 

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May not need it. The sight glass is a good reference tool but the outside temp. has a lot to do with the performance. Continuous bubbles may appear in a properly charged system on a cool day, under 70Deg.

If it is cooling and you have occasional bubbles this is normal. A steady stream can be diagnosed by blocking off half your condenser from air flow. if the bubbles clear your charge is fine. As Jim said, you don't want to overcharge. A good shop may be able to find small leaks with a sniffer but good r12 shops are tough to find. Thats why I decided to learn it and work my own. If it blows  cold, 70 Deg or under outside and you have some bubbles, it's probably fine. if determined to add more, 1/4 to 1/2 lb at a time. don't want an overcharge. Tough chore when the small cans are 3/4 of a pound.

Edited by Tder1 (see edit history)
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One thing that is very SELDOM mentioned is refrigerate oil. When the system leaks, since oil is carried with the Freon,  oil leaks out ALSO. It's ALWAYS advisable to add a small amount of oil ALSO. Most times if you fill the system once a year add one ounce of oil of the proper type. Lack of the proper amount of oil  is USUALLY the cause of catastrophic compressor failure. Another way to tell if the Freon content is low is that the low side, I think, pipes will start getting "Frost" on them.  I ALWAYS add both a low & high side filter to help keep contaminants out of the system. Do it ONCE & do it RIGHT.

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Thanks to all for your insights.  It was probably only 50~55 degrees F on the day I checked the sight glass, and I didn't let the A/C run for more than 2 or 3 minutes.  Based on what I'm hearing I will wait until a warm day (70 F is predicted for Saturday) and try it again.  Next time I will let it run for awhile and check the temperature at the dash vents.  I was nervous about running too low -- especially with R-12 and I am also mindful, as telriv mentioned, that lubrication is crucial.  I REALLY do not want to damage the original compressor (and contaminate the rest of the system).  I'll also check around my area (Syracuse, NY) to see who, if anyone, is capable of servicing an  R-12 system (just in case).

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