A/C Conversion to R134A

[Guest Anonymous]

Anything I should know about? Everything looks pretty simple, I just hate the stuff because if dosen't cool for crap. Well, at least when you convert. I know it works great for new cars that are designed for it.

 

I have a freind who is letting me barrow his kit so I can charge everything up, all I need is the refrigerant.

 

Nic

[Guest Anonymous]

I think you'll want to flush the system (sorry I don't remember what with) with something before going to 134a, memory serves theres a chemical reaction between the old lubricant in the freon and some compond in the new 134a that isn't good. As far as it cooling not as well, maybe a bit less, but 134a is real sensitive to overfilling, if you overfil it, it'll drop its abilty to cool way down. Oh yeah, new O-rings as well at all your fittings, the nitryl type I'm told. (green o-ring) Good move to switch though, last time I had freon put in my truck it was 250.00 for the freon and a conversion to R134a was 300.00 (ironic, the gas for the 134a charge is what 20 bucks tops?).

 

Regards and good luck,

 

Lone

[jeromio]

Auto parts stores should have the oil flush. I believe the major incompatibility issue is with the oils.

 

Regardless, you'll want to pump the system down to vacuum first and that will obviously clear any residuals.

 

Is this a leaky system that's empty, or is there R12 in it now? That R12 is worth saving - only because it's soooo expensive. If it still has R12 in it, I'd work out something with someone (like a shop) who has the retrieval system.

 

I kick myself for not buying a 5 lb tank of R12 when I could've - "Hrm, $25 - that's like 5 6 packs of good beer." Idiot. That 5lb jug is worth like $500 now....

[pparaska]

jeromio, I'm with you - I almost bought a tank of R-12 years ago and never did.

 

I've heard that yes, it's the oils that are a problem. But if you use an Ester based oil with the R-12, there isn't a problem. I'm getting ready to charge my system this week. It's getting hot and the lift-off date is very close.

[Guest Anonymous]

Those are some good points! I'll pick-up the flush while I get the other stuff. I know there is still oil in it.

 

The system does have a pin hole leak somewhere in the coil pack (under the dash). I just wanted to spend $30 bucks or so and see how well everything worked. When I had it tested (a year ago) everything was in perfect condition. The guys swaped out all the o-rings, installed a new recv/dryer and leak tested the entire system (thats how I know it's the coils). Oh...it was all new and free.

 

The oil package you can buy is said to come with a stop leak, would this be a stupid mistake to use or will it not damage to compressor?

 

Thankx,

Nic

[denny411]

I`ve got my own evacuation pump and r/12 as well as 134a guages. I`ve done numerous ac jobs over the years and have had very good luck with 134a conversions. my truck has been my test bed for the simplest conversion of all. The r12 system had a leak so I had no r12 left in the system.

1)I removed the accumulator,and drained all remaining oil from it.

 

2)I filled the accumulator w/ 4 oz of esther oil, and plugged the ends to keep the desicant inside from absorbing moisture.(if the desicant is exposed to the atmoshere for more than 20 mins, it is not usable)

 

3)replaced all o`rings with the "green" 134a compatible ones, being sure to liberally oil each one.

 

4)I then reassembled all components

 

5)hook up guages and vacume pump and pull 24hg for 1/2 hr,stopping after the first 5 to insure that it will hold a vacume(it must hold steady vacume for a minimum of 5 mins)

 

6)bypass the low pressure shutoff switch at the accumulator with a paper clip and,install 1 can of 134a stop leak and detector(this will show red wherever a leak may occur, making future diagnosis easier.

 

7)start vehicle and add 1 can of 134a oil charge

 

8) then fill with 134a only(should not take more than a total of 35oz.)

 

9)remember that evaporator tempurature is directly related to your low side pressure. evap, temp will usually be 3 to 4 degrees warmer than your low side guage reading (the temp at the vents will vary somwhat more)

I like to have the low side guage at or around 35psi.

you will want to use a fan to force air through

the condensor, this will aid in getting a more complete charge. your guage readings will also be more accurate to real world operation.

 

I have been running the ac in my truck without any problems for 2 years.(with the original r12 accumulator, and no flushing) If you have the vent pointed too close to your head it will give you a headache.the temp at the vents is 42 degrees.

I buy my 134a at Sams club in a 30lb cyl for about 80.00 to give you an idea of how many systems I have charged/converted. I`ve been through 5 30lb cyls

I converted our 92 explorer about 5 yrs ago and it is still as cold as the day I finished it.

 

The stop leak will not hurt your compressor,

and if you need the evaporator, I think I`ve got some frome Z`s and zx`s

[Trevor]

Tips:

Change the receiver/drier.

Flush each section of hose separately.

[Guest Anonymous]

Wow, thats great news! ..and why can't you live closer to me?!?!

 

I'll let you know if I need an evap can.

 

Nic