A/C questions

[Guest Recian]

I know i've posted before and there's been list after list of a/c postings recently but i wanted to know. I found a bulletin by GM in 94 for retrofitting the reatta. It says to use V5 retrofit oil when doing it. If that is not available to replace the compressor. Most auto store retrofit kits come with ESTER oil. I want to make sure what i should do when it comes with oil before I retrofit the system. I know the accumulator and orrifice tube should be replaced but would the ester be safe for the old R12 compressor? I have to use 2 seperate machines to vacuum the R12 system to remove moisture and charge with R134. The R134 machine is what will inject the oil prior to charging the system so it's not like i can keep all the old oil in the system and reuse it because it'll be in the R12 machine's drain after performing the vacuum not the R134 machine. The vacuum is the key to making the R134 systems cold. It will cause the mosture to boil under pressure which turns it into gas that can be vacuumed out. At least that's what I learned from Honda and believe it or not the longer i've vacuumed any R134 a/c system the cooler it was after. So not vacuuming before charging is out of the question too

Edited June 22, 2011 by Recian (see edit history)

[padgett]

Thought most conversions used PAG, which is a golden color ? Do believe an R12 system needs to be flushed prior to conversion to remove the mineral oil. I have needed to replace quite a few compressors but only one manifold (cracked). Am getting a lot of experience lately that I had not expected.

Agree with vaccuuming deeply, I usually pull for 60-90 minutes then let sit overnight to be sure it holds the vaccuum. Not sure what you mean by two machines unless one to extract the R12 and another to inject the R134a.

Seem to be going through another shift, R134 is 2.5X what it cost two years ago but seems to be dropping slightly recently. R134a is now about 2/3 the price of R12 (but you use less).

So leaning a lot recently I never expected to need.

[Guest Mc_Reatta]

We don't have V5 compressors in our Reattas, they're HR6s so you don't have to worry about finding that oil.

If you're reusing the old compressor you need to pour the old mineral oil out of it and use PAG 150 oil along with the new accumulator and o-tube. No need to flush system (you can't flush a compressor or accumulator anyway). Emptying the compressor and replacing the accumulator will get rid of most of the old mineral oil and evacuating will get some of the rest. Removing the R 12 with just the machine will leave some oil oil in the compressor and accumulator.

Use a full 8 oz oil charge. You can pour 3 ozx in the compressor port and let soak, and either put remainder in the accumulator or add via machine. Not sure adding all the oil via the machine, especially with a new compressor, is a good idea since it will start dry unless compressor starts with oil installed. Still need to adjust amount added by machine to not overcharge with oil.

If you were replacing the compressor also and flushing, you could then use ester oil. But conventional wisdom is that since mineral oil will mix with ester oil but mineral oil and most likely the mineral / ester oil mix will not circulate along with the R 134 and keeps the system from getting proper lubrication.

Ester oil is not considered as good a lubricant as either mineral oil or PAG oil so the best reason to consider it is because it is less hygroscopic. But if you use fresh double end capped (DEC) PAG oil and pull a strong vacuum you shouldn't have any problems with using the recommended PAG oil.

Think the popularity of recommending ester oil was because DIYers probably didn't have equipment to draw a good vacuum on a system to get all the moisture out. Moisture and R 134 and or left behind flushing agents will combine to make acids which will eat away at the vital components and reek havoc on the system.

[Guest Recian]

I am using 2 a/c machines padgett. The R12 machine doesnt have refrigerant left so all i can do with it is vacuum and recover. Ill use the R134 machine (equipped with PAG150 with dye) to charge the system. Exactly what do i need to do to flush and how should I flush it to remove the old oil with the machines Ive got access to. And so the PAG is safe for the compressor then? R134 prices mean nothing to me but they always drop in the summer time. It's $15 per lb now. Its usually $15 per 1/2 lb in the winter time but our machine has a 30 lb container so im good

[Guest Mc_Reatta]

Sounds like you have access to 2 recovery machines.

Flushing is usually done in a shop by a different machine designed for that purpose.

Recovery machines typically don't remove all of the old system oil as it pools in places when simply pulling a vacuum on the ports can't get to. It is removed by flowing a flushing solvent through the system witch dissolves the old oil and then it is pulled out of the system. The solvent then needs to be completely removed from the system by using vacuum and air drying lest any be left that can break down the new oil or react with any moisture in the system and produce acids that can attack the metal parts. This process can be done by hand or with a flushing machine.

Since most of the oil will settle in the compressor and accumulator, recommendations are that the accumulator be replaced along with the o-tube during a repair or retrofit operation, and if the compressor is to be reused, that any old oil in it be drained of the ports and the new oil put in its place and the system reassembled. Flushing the system is then not necessary or recommended, but then PAG oil, not ester oil is recommended to be used. This is for a system that has not suffered from "black death", nor has any other significant debris present on the orifice tube or observed elsewhere. In that case flushing needs to be undertaken on any components that will not be replaced. In a Reatta, that would typically be the evaporator, condenser and lines. In many newer systems with high efficiency condensers designed for R 134, they can't be flushed adequately, and should be replaced, but the Reatta doesn't have one of these.

[padgett]

Well I definately will take the advice of the pros, life is a learning process. Do have a new condenser coming in so might as well use it. Am flushing the lines/manifold/evaporator with alcohol first and then a/c flush. Do have a flushing tool coming in (Interdynamics FK-1) to asist with the process since was concerned primarily about flushing the evaporator.

Do have a question: have drained the new compressors and refilled. Is PAG a clear golden liquid ? If not what do new compressors come with ?

[Guest Mc_Reatta]

PAG oil is clear but can be different colors depending on additives. i've heard it described as a light golden color, so your clear yellow sounds like OK especially if it has a leak detector dye added. . Last type I used had ICE performance additive in it and was a clear blue color.

Not sure if color is used to indicate what viscosity of PAG it is. Most of the bottles on the shelf are opaque so you can't just look at all the different oils on the FLAPS shelf and tell much.

Didn't the new oil come in a marked container?

Here's a site with lots of pictures of PAG oils:

http://www.thefind.com/search?query=r134a+pag+oil+a%2Fc+#page=2

The 13th one in is GM brand oil. Looks to be 8 ozs of 150 DEC PAG oil with no additives. That might be the best one to use if you can get some.

Edited June 22, 2011 by Mc_Reatta (see edit history)

[padgett]

Was in the new compressor from the vendor. Label just said "PAG".

[Guest Recian]

stupid question. where is the o tube in the reatta? gona take it out and inspect it to see how far i need to go to fix my ac

[padgett]

See pic. Need to remove clamp screw about center of firewall, then can move enough to seperate. Needlenose pliers should be able to grab end and pull out.

Edited June 22, 2011 by padgett (see edit history)

[Guest Recian]

got it thanks for the pic