'85 Suburban A/C

[rke1]

I keep getting conflicting information on the type and quantity of oil and R134 charge amount on converting from R12.

Have new compressor, hoses, drier etc and want to do everything correctly to minimize problems.

Any other suggestions would be appreciated

Thanks

[jbell]

my 2c, forget the convert to r134a. You'll get less cool, and have to mess with an oil change / flush. Search internet for envirosafe, it's a hydrocarbon refrigerant that replaces r12 and blows colder. Basically propane/isobutane and "other stuff"

Makes chev a/c's actually work like your typical japanese ac "blaster" (read, colder than you can stand.....)

[TimK]

Rke1,

Do not use any refrigerent in your vehicle with propane or butane in it. Not only is this dangerous but it's illegal. I would also doubt you would ever find an A/C repair business willing to service your system once you contaminated your system. However there are alternatives to R12 that do not have flammables and that are legal to use.

Check out the website at http://www.imaca.org/toc.htm

IMACA is an organization serving the mobile air conditioning industry. The link above is to their online technicians guide which discusses the converion of R12 to other refridgerants. Depending on what type of alterantive refriderant you choose, will depend on if you need to also change out your existing A/C hoses to "barrier" type hose". I pasted below a list of the legally allowed R12 substitutes and those that are not allowed.

Acceptable Substitutes, Subject to Use Conditions

HFC-134a (R-134a)
FRIGC (FR-12)
FreeZone/RB-276
Ikon-12
Freeze-12

Listed by SNAP as Acceptable, Subject to Use Conditions, the following refrigerants contain R-22 (HCFC-22). Therefore, when retrofitting to these refrigerants, any existing "non-barrier-type" hose must be replaced with "barrier-type".

GHG/McCool/Autofrost-X3/R-406A
GHG-X4/McCool Chill-It/Autofrost-X4/R-414A
Hot Shot/Kar Kool/R-414B
GHG-HP
GHG-X5
Unacceptable Substitutes for CFC-12 MVAC Systems


OZ-12 (Due to flammability)
HC-12a (Due to flammability)
Duracool 12a (Due to flammability)
R-176 (Due to composition)
R-405A (Due to composition)
Any flammable substitute for CFC-12 is unacceptable and illegal to use in the United States in a CFC-12 mobile air conditioning system.

Also, If your R12 system is working but only needs a recharge, then consider just using R12. It's expensive but that's what your system was designed for. All mobile systems leak a little. (Some very little others more.)Running the A/C periodicly in the winter time helps to keep the oil circulated and to keep the seals from drying out. I doubt of any replacement gas would work exactly the same as R12 just because each alternative gas has it's own characteristic curves. Your system was designed to run at its optimum performance with R12.

Other then R134a, the two most popular R12 compatible refridgerants I know folks that are using are the R414B "Hot Shot" and Freeze 12. I like the Freeze 12 since it doesn't require the barrier type hose. (By the way, I believe R134a does require the barrier type hose.)

You do need an EPA certification to buy A/C refridgerant with exception to R134a. However, this is very easy to get. The IMACA website provides the free study guide on-line and the has an online 25 question test (open book) for a small fee. With 2 hours of reading and 15 minutes to take the test you can be certfied to buy all the gas you want, even R12. Here are some other links I have on the Freeze 12 products. There is some good technical information in there on the amount of R12 versus Freeze 12 quantity to use.
http://www.epa.gov/ozone/snap/refrigerants/macssubs.html

http://autorefrigerants.com/co00030.htm

http://www.freeze12.com/

http://www.freeze12.com/convdata.htm

http://www.aapak.com/Qstore/p000176.htm

http://www.technicalchemical.com/msds/6030.pdf

TimK

[ 07-20-2004, 08:44 PM: Message edited by: TimK ]

[jbell]

Should have been clear -- envirosafe is an approved retrofit, and legal, if you go R12 --> R134a --> ES12a. Or R134a --> ES12a.

Envirosafe is only illegal under epa regs, if you do a direct R12 --> ES12a conversion.

Here's the clip from envirosafe.

Enviro-Safe is a zero ozone depleting "second generation" replacement for R-134a and all other substitutes for freon that are non-ozone depleting. EPA's Final Rule, issued April 1, 1994, states:

"In this final rule, the Agency has determined that second generation replacements, if they are non-ozone depleting and are replacing non-ozone depleting first generation alternatives, are exempt from reporting requirements under Section 612"

If an automotive system is "first generation" (i.e..- has 134a fittings and contains no freon) it may accept a "second generation" refrigerant like Enviro-Safe.

In a safety study, the prestigious Arthur D. Little scientists concluded that hydrocarbon refrigerants pose no significant increased risk or hazard over freon. (copy of report available at cost of US$5.00) A $3,000,000.00 insurance policy is maintained to back the Enviro-Safe guarantee. To date, no claims have ever been made against this policy.

[ZZ]

I can't think of the name, but there is a 134a conversion oil now that will mix with R12 oil without having to flush the system.

[nape]

You need ester oil. It will blend with the 12 oil and work with the 134 freon. You replace the freon at 80% of the volume of r12 required. I usually replace the o rings and vacum before filling. Works fine. I have recently began adding a booster to the 134 that seems to help.

Wayne

[Deib]

castrol makes a oil just for conversions.
it's called retro.

My '84 blows 42 out the front and 37 out the rear on high idle.

I think that is cold enough, but not sure, hmmm is it normal for the kids to ask for coats on a 95 degree day?

Ask 50 people get 50 answers.

Decide how long you want to keep the vehicle and go from there.
R134 is still being produced and it's cheap. The OE's are using it so it will be around a while, no cert needed to buy it.

If you are going to dump it in a couple years go with a drop in replacement.

Oh and if all that stuff is new and you flushed the system, 4 ounces is plenty, If you didn't flush 2 ounces.

[Mark Krieger]

My two-cents worth...

I learned a ton about working on air conditioning at www.aircondition.com (http://www.aircondition.com)

One the left side of the main page is a "Questions" link that's actually a discussion forum. Post your question there and you'll generally be able to get some very good advice from some of the people who are professionals. At least take the time to read the questions already answered and you'll get a good education.

The most important lesson I learned is the importance of craftsmanship and keeping everything clean. The most frequent reason that do-it-yourself repairs fail or deliver poor results is taking shortcuts.

Post your question over there to be sure, however I think you should take the time to clean and flush your system and restore it to like-new and you'll get very good results. Mixing oils and taking shortcuts seem to deliver poor results.

[cschneider]

I did a Freeze-12 direct conversion, meaning no change of seals or anything just a flush and fill on my '85 suburban and have been very satisfied with the results.