A/C conversion experts

[BJM]

I read the GNTTYPE conversion link which is really good. My question is this. The author of the article had to replace his A/C compressor so he put in some oil. On unopened systems he says to charge the system after evacuating with oil first and the the R134. Since the old R12 oil is incompatible with the new stuff, does it come out during the evacuation process?

Also, I assume the R12 that is left in the do it yourself method just gets dumped to the atmosphere (cringe), correct?

I have a set of R12 gauges and a old commercial vaccum pump. Do I need adapters to use these gauges? Are they adequate for this job?

Thanks,

 

[turbojimmy]

I wrote that

...but I'm not an expert. Just bought a book and tools and did it.

The oil does come out with the evacuation process, though. Even if you're DIY, you can take it somewhere to have it evacuated and vacuumed down. Then you can add the R134 and new oil yourself.

You really should use R134 gauges. I'm not sure if adapters exist to use R12 gauges with R134.

HTH,

Jim

 

[49-blues]

adapters do exist in some of the newer recharge kits or some of the local auto supply houses or refrigeration supply houses.HTH

 

[scottyb]

My friend and I have done several cars. We are not experts and we have not done the Buick. The reasons for our conversions are failed compressors. We do the poor boy method:
- blow out evaporator and condenser with compressed air.
- use new o-rings wherever we break a seal
- use a new dryer and oriface tube/expansion valve.
- add esther oil per compressor manufacturer recommendation. usually very little.
- vacuum it down, verify hold vacuum.
- pump in r134, I don't know the pressures, he's the guru.

I know that our methods may not be what is recommended, and the oldest one has been in service less than 3 years, but we have no failures yet. Since we had problems with an adapter valve more than once, we agreed to use the old standard 12 gauges and connectors. The gauges are the same, only the connectors are different.

 

[BJM]

I assume then that the R12 oil boils off and evacuates that way while under vacuum. I don't need to wash out the system in any way.

I guess the only connection I have to make then is the R134 can to the yellow gauge hose if I keep the R12 fittings on the car.

I assume the R12 fittings work fine and that they get switched only so that service people know that the refrigerant has been switched.

 

[Gokou]

If you evacuate a previously in-service system, it will remove the oil that is suspended in the refridgerant, however, the majority of the oil in the system will remain in the compressor. The compressor must be removed and drained. However since you usually replace the compressor when you do an R-12 to R-134a conversion, this isn't a problem. If you don't change out the compressor, take it off the car and drain it.

And as for the adapters: yes, there are adapters made to convert the R-12 fittings to R-134a fittings-- they're made just for conversions. They screw on to the old R-12 fittings.

 

[scottyb]

I called "the guru" (not an expert, mind you). He said that the esther oil is friendly for both 12 and 134, that's why we use it. Apparently, the oil used in 134 original systems is different.
I think you are correct about the fittings. I think the new ones are used to avoid mixing the 2.

 

[Steve Wood]

Use the Ester oil....not the PAG

 

[Gn-Krazzie]

Is this true if I want to change to R134 i have to change my compressor. Please tell me the reasons for this ??

 

[PaulRV6]

No, you do not have to change the compressor for the conversion. It was thought early on that the hoses and compressor were not compatable but that is no longer valid. Must change the oil though and a new dryer. If hoses are old and cracked then you might see leakage since R-134 is lighter and has a tendency to leak easier. Need the correct fittings and that is it.

paul

 

[Nick Micale]

Originally posted by Gn-Krazzie
Is this true if I want to change to R134 i have to change my compressor. Please tell me the reasons for this ??

If you have an original 15-16 year old compressor, would be a smart move to change it if converting to 134a.

There are 2 good reasons. First, it is probably at the end of its normal useful life. Second, 134a runs at a higher head pressure and would probably blow a seal or something.

Recent replacement compressors are made different [better] and will be compatible.

 

[BJM]

I don't know what to do

So many opinions on this topic.

My A/C is totally original, never been charged to my knowledge. Over the winter it seems to have lost some charge. It still makes cool air but the compressor cycles a lot. I get about 30 seconds of cool air and then it switches off for a about 5 seconds and then comes back on. I figure I just need a top off of Freon. R12 is not allowed to be used in Ontario anymore at all. I either smuggle some from somewhere or switch over. The frustrating part is that if this were 5 years ago I would only need minor maintenance.

 

[49-blues]

you can reclaim the r-12 in the system,put it in a vacuum,check for leaks and replace with 414b (hotshot),which is 10-15 degrees colder than r-12,cheap as 134a and has many other benefits-it is a direct dropin and compatable with the existing oil in system and r-12 or 134a.HTH works great-i have done three cars over to this with no ill effects.

 

[Sborel]

BE ADVISED! It is usually hard to find shops that use ALTERNATE(any refrigerant other than r-12 and r134a) refrigerant. Modern a/c machine have identifiers built in to prevent contaminating equipment Therefore converting with alternate freon will probably render it DIY only system. ALSO dont use any refrigerant that has propane in its formulation, can you say BOOOOM!!!

 

[BJM]

Okay, what is R12a?

I have never heard of it before. Where can I go to read up on it. Also what is this HOTSHOT that was mentioned above, I have never heard of it either.

I am glad there others who have done this before me otherwise I would be at the mercy of some local ripoff artist.

 

[Nick Micale]

Originally posted by ILBCNU6
This isn't California so their pollution laws don't apply any where else........................................ Everyone can choose for themselves what to do to their A/C systems. Just another opinion! Gene PS. Minnesota does sell R12 and several shops install it too! ($90 including 1# of R12)

Since Arizona is more dependent on A/C and has more older cars than lots of areas, R-12 has always been available and sorta reasonable, like $30 a can.

 

[salvageV6]

Well believe it or not our Mechanical Engineer masters at MIT just converted his system over to pure propane. 1983 Beemer.

Said the flashpoint was higher for propane than R134a. I didn't check this out for fact (MSDS sheets) and I think the guy is a bit off but he's happy.

He only makes 80K a year too. 400K mile car.

Pure propane works better for cooling than R12 too.

If it leaks out it dissipates real quick, so he says.....

R134a isn't all that it's built up to be, then again it is legal and cheap. I can live with that.

 

[49-blues]

bjm

hotshot is 414b-a direct dropin refrigerant for r-12 and 134a sold in your local refrigeration supply houses which is about 10-15 degrees colder than r-12 and about 25 degrees colder than 134a.it has alot of added benefits,its ozone safe and cost me about $203.00 for 30 lb can which makes it about $6.75 a lb.HTH