I converted the system to the R135a last year. I took it to a place that put the system under vacuum for 1/2 hr before filling. Worked great. The other day I tried the system and the compressor didn't come on. My guess is that fluid/gas leaked out.. Question: Would you buy the die and guages along with a can of R135a and try to find the leak yourself and then refill OR bring it back to the garage that filled it and have them do it. I'm wondering if i have to vaccuum the system again before refilling. Either way, I have to find the leak first..


[Modified by Koz, 4:17 PM 4/9/2003]

 

Yep, got to get the moisture out first, then the vacumn will help suck the new stuff in :)

Did the shop do the full conversion, o-rings and all that? If so I would take it back to them. If not and you have a good working relationship with them, take it to them to find the leak, then fix it yourself. Then back to them for a re-fill. Or just let them do it all.

tom...

 

A Number of issues-

Putting in a can of DYE, well.......it's messy ,sticky and it sucks.
I happen to have the electronic leak "Sniffer" , so I'm not talking up
a braggert storm here,'cause i used the OTHER items over the years,also.

Having the system recharged and "Leak Checked/Detected" is probably not a whole lot more expensive than the "Ooze and Drool" detection method! ;)

AND NO CLEAN UP COSTS EITHER! :p:

It -MAY- also be a case of having "Non-Barrier" hoses on the '80 model.
Molecular level leaks are the often the norm for older hoses on R12 systems.

The leak -CAN- be so slow it take months to show, but it can be quick as a day or two as well.

Other than the cost of R12 issue, any other reason for the 134a conversion?

-IF- you still have some reasonable pressure on the system,even if it is low.......then I'd vote for a refill and go! :D

If the system if "flat", then yes a leak finding expedition should be warranted.

Refitting the whole system with modern barrier hoses will be involved and a bit costly,but would certainly CURE the problem .

ENJOY!

 

As long as there is ANY pressure in the system you don't have to vacuum it. If all it needs is one can of R134a a year, it's not even worth messing with. Just get the refill kit from an autoparts store and put a can in it every spring. The cans go for about $5-$6.

 

Nope.. couldn't see a reason to keep the R12 system. It wasn't working and needed filling. The cost of one fill-up of R12 almost paid for a new compressor and conversion kit. I did the work myself. Pretty easy to change the o-rings. I thought I did a great job and after it sitting on vacuum for 1/2hr I would have thought any leaks would have been found.. ie.. vacuum would have dropped. It lasted all season and worked great.

I really don't want to do the can a year deal especially with a new system.. shouldn't have to.. guess I'll buy the guages and kit and see how much is in there.. if any. With the R12 I saw oil around a joint that I suspect was leaking. I don't see anything with the new system.. Then again, it's only one years worth of coolant lost.. maybe not enough to leave it's mark..

What kind of mess does the sealant have? It comes in a can like the coolant and pumps in the same way. I thought if it leaks out, it seals itself. Not the case? With the sealant help with the non-barrier hose problem you mentioned?

 

A lot of the R134a available in parts stores now has some kind of built in leak sealer and line "conditioner". Just make sure to put it in the low pressure side and keep the can upright so it sucks gas and not liquid with the compressor running. Once you get enough in (probably just from the pressure of the can) the compressor should kick in. If not, you might have to jump the low pressure switch. That switch could be the culprit too.

 

In any case it is well worth the investment of 60 or 70 bucks to have a set of gauges to diagnose the problem and enable you to do it yourself next time. Any chance I have to buy a tool, I take. :smash:

 

Under advice of some experts I talked to at http://www.oldairproducts.com (all they do is A/C systems) I have decided NOT to use 134A in my Vette. 134 runs at a considerably higher pressure than the good old reliable R-12. The folks at old air say the vettes seem to have a lot more problems with this then other cars. When you converted what was changed? You didn't mention what year you had but if you have a POA valve from the 12 system it won't work right with 134. Bottom line though is you must locate your leak before recharging the system with either. I personally don't believe in the dyes, and I am a refrigeration pipefitter by trade, do mainly service work on commercial and industrial systems.,Dye will sometimes void a manufacturer's warranty as well. If you can get your hands on a good leak detector (Detek or GE) you shouldn't have any problem finding your leak. A evaporator leak will show up at the drain tube under the A/C box. Compressor shaft seal leak will usually show oil in the clutch. Most common places are any o-ringed joints and the crimp connectors on the rubber hoses. For what it's worth, I am planning to use a product called "Hot Shot" which is a drop in replacement for R-12, is ozone friendly, and operates at slightly lower pressures then 12. Even though this product has not been DOT approved, who's to check? Hope this helps, good luck with your project. :cheers:

 

What problems would that be? The C3 has the same AC system as all other GM's of that vintage. Even the same compressor. The A6 can cool a house.

I've been running R134a for... oh it's going on 4 years now. My vent temps are 10F COOLER than the service manual lists as normal. 42F out the vents on a 90F day. Only problem I've had has been a leaky original high pressure fitting. Would have leaked with R12 too, though. As for the POA valve, I got one from NAPA and it is adjustable. Turning the adjustment 1/4 turn CCW sets it for R134a.

Not trying to slam you, just relaying my good experience with R134a.

 

zwede, certainly no slam experienced at this end. 134 runs about 50 pounds higher on head pressure then it's 12 counterpart. Underhood ventilation on vettes is not as good as most other cars. I would never say it won't work, because it does, but I can't believe it doesn't require a little more horsepwer to do the same job as the 12 did. I see the same kind of problems with it all the time on refrigeration systems, causing high discharge temperatures (measured 6" away from the compressor on the discharge line) and premature compressor failures. That is why I will use the "hot shot" or maybe I'll even use new 12, just depends on what I have available when the time comes.

 

Some more info...

Pulling a vacuum and holding it doesn't mean your system doesn't have a leak.

I pulled a vacuum on a Vette using a new Yellow Jacket pump and the vac held for 2 weeks. Didn't drop at all. Filled her up with R12 and within one day, the R12 was gone.
That was an expensive learning experience.

The system reacts differently under high pressure than it dsoes under a vac.

 

I didn't see 50 lbs more head. More like 20-30. I use spal fans and wired it so that one fan turns on when the AC is on. Maybe it does use a little more power to turn the compressor, but it is not noticable. As for premature compressor failure, I can't believe anything short of a grenade will damage an A6. Those things are massive.

Reason I don't like products like Hot-shot, freeze12 etc is that they are blends. IF you have any leak, even a tiny one, the lighter component of the blend leaks at a higher rate. So you can't top it off like a R134a or R12 system. You need to evacuate all of it and start over.

 

zwede, you have certainly done the right thing with your electric fans. That is one of the things the folks at old air recommend for a successful 134 conversion. The compressor failures I was referring to are not the A6 (which I know is just about bullet proof) but commercial refrigeration compressors (reach in coolers, etc.) I must beg to differ with you about the blends losing proportions however. This has certainly not been a problem in the refrigeration equipment I service. It's possible it could be more of a problem in cars however because of long periods of off cycles, I'll have to wait and see.

 

I run R134a in my stock 69 system and it is just as good as the R12. I have the stock fan and a big block. I stay cool even on those hot humid Florida summer days. (96-98deg). I run 26psi on the low side. R134a is just very sensitve to the correct amount.. Just a little over and the head pressure will go up. You need to experiment with the amount... Each system seem to be a little differerent.

 

Can you explain what you mean by the head pressure will go up? I can see putting a guage on the low side and filling the system until a certain amount but how do you test the head pressure?

 

"Head pressure" is the high side or discharge pressure. You need a manifold gauge set with high and low pressure gauges to check the head pressure.