R12 ain't cheap - Help me avoid $$$ mistake.

[ssuesens]

I have been tinkering with my factory AC since I bought the truck last fall. I believe I am ready to pull a vacuum and recharge the system with R12 and mineral oil. As you know - R12 is EXPENSIVE and I don't want to make a costly mistake.

Here is my progress to date:
Disassembled and cleaned all in-cab components (vent, heater core area, etc)
Replaced all vacuum lines and verified all are functioning as designed
Verified compressor is kicking on when switched on in Cab
Replaced leaking condenser (pinhole) with used unit - (pressure tested and flushed)
Replaced Dryer/accumulator
Replaced Schrader valves and o-rings
Charged system with 150# Nitrogen to verify no leaks- pressure has held for 7 days
Paid way too much for 12 cans of R12 (USA) Freon

I think my next steps is to pull a vacuum for one hour as a final leak check. If it maintains vacuum, I will then add 3.25 LBS R12 (per assembly manual) and some quantity of mineral oil. Manual says 10oz but how much is in there now?

Before I start tapping cans of this liquid gold R12, are there any other steps or final checks I should make?

[Clavo106]

R12 is the good stuff man nice and cold!!! just Don't mix Freons. 16oz for 1 pound of air.

[Big Kev-O]

Did you remove the oil from the compressor? Most of the oil stays in the compressor. If you had a leak you could have lost an unknown amount.The only way to make sure you have the correct ammount of oil is to remove all the oil from the compressor, purge all the oil from the system and refill with the proper ammount.

[hugger6933]

Try freeze 12. It is about a 1/3 the price of R12 and does real well. I used to use a ton of it before the newer stuff is what is in the trucks now. I charged a 00 Silverado the other day and it blows down to 42 degrees driving down the road.

[Katrina/10]

The only way to know how much oil is in a used system is to drain it all out and measure it. Not easy to do.

[Xeen]

Some of the better shops will have a machine that will not only recover refrigerant but oil as well and the system will be ready to go, you could have it serviced then add your cans after.

[ssuesens]

Thanks
I was hoping not to remove and flush the compressor but if the amount of mineral oil (10 oz per assembly manual) is critical, I guess I will pull the compressor.

[ssuesens]

Originally Posted by Xeen

Some of the better shops will have a machine that will not only recover refrigerant but oil as well and the system will be ready to go, you could have it serviced then add your cans after.

Thanks Xeen
I am going to run up to my local ac shop and ask them to take a look at the system before I charge it. I just want a second set of eyes to look at it. I'll ask them about the oil recovery and if there is a way they can test the compressor. Would asking them to flush the system for me be a good idea?

[Xeen]

Originally Posted by ssuesens

Thanks Xeen
I am going to run up to my local ac shop and ask them to take a look at the system before I charge it. I just want a second set of eyes to look at it. I'll ask them about the oil recovery and if there is a way they can test the compressor. Would asking them to flush the system for me be a good idea?

It looks to me like you have done everything that needs to be done short of recovering the old oil and adding new oil.

[BruthaMan]

Check each and every hard line at every fitting, including at and on the condenser for any twists or kinks. This caused me a huge headache with a high pressure reading on the low side port that took forever to track down on my '72.

Everything else was perfect. I had meticulously cleaned, new o'rings, proper vacuum, the whole nine yards. Somehow managed to twist the metal tube on the condenser when hooking up those hoses and kinked the aluminum enough to restrict the flow, which caused an abnormal high reading on the low pressure side.

[ssuesens]

So I stopped by my local ''Old School' ac shop this afternoon. He looked over the entire system and said all looked ok. He looked at my rebuilt ac compressor and suggested I swap it out for a 10 piston aluminum A6 style compressor. For $230 he said it would out perform any A6 model with less weight, noise and power draw. He will put in the mineral oil, I will install the compressor, and then he will draw vacuum and fill the system with my R12 Freon. All this for $35. Hopefully I will have cold air by wed or Thurs!

[57larry]

why not just convert it to 134A? it doesn't cost much and it ain't hard

[ssuesens]

Everything I've read says the R12 performs better (103 in Dallas today) unless you add a cross flow condenser. Plus I already have 14 cans of R12

[MARKDTN]

Originally Posted by hugger6933

Try freeze 12. It is about a 1/3 the price of R12 and does real well. I used to use a ton of it before the newer stuff is what is in the trucks now. I charged a 00 Silverado the other day and it blows down to 42 degrees driving down the road.

In no way trying to argue with Hugger. But here is a little supplemental info on refrigerants so you may have a better understanding- but don't just take my word for it-do some research yourself. I believe Freeze12 has been discontinued now anyway. Even so, I would be very cautious with this-and any blend. The short version is either use R12 or R134.

The long version is this:
1-Freeze 12 is a mixture of R134 and another Freon. The reason it exists was really for conversions on R12 systems using existing parts. It was thought to be more compatible with the existing oil in an R12 system. In many cases it is OK, but if there is any residual moisture from a system left open for a long times and not replacing the dryer and compressor and flushing the evaporator and condenser, there is a risk of failure.

2-many blends (not freeze 12) contain butane. Do you really want butane at high pressure in your engine compartment?

3-Many blends contain molecules of radically different size-think BBs and Ping-Pong balls. When you need to add some charge at some point all the "BBs" are gone and the "ping pong balls" remain. You cannot get a balanced charge without blowing the whole charge and starting over and the remaining mixture can be caustic to hoses and seals or cause pressure issues.

I see no reason at this stage to use anything other than R12 or R134. Supplies of both are plentiful and relatively inexpensive. A/C is not a place to go cheap IMHO. I know there are people with success with all of the above products, but you will also find a lot of failures. Why chance it when the original refrigerants are out there and work well? You may spend more money and time than just do it right the first time. To me I will put R12 back in vehicles originally equipped with it.

To the OP. Sounds like you are on the right track. You do need the right amount of the right oil. You could guess how much is left and how much to add, but you are probably better off long term to just bite the bullet and get the old out and add the correct amount especially if the system was open for a long time.

[volksworld]

basically the r-12 substitutes were for the " i dont want to spend the money to do it right, i just want to get another summer out of this clunker" crowd...with no regard for long term effects...so glad i was required by NY state to spend 2 grand on a recycling machine and eventually being afraid to use it cause i had no idea what crap mixture i was pulling out...and that i can still buy "illegal" r-12 twenty years later...

[volksworld]

i've also been checking some a/c related stuff on here (just picked up a factory air truck and weighing my options) and there seem to be complaints of seal failure on the rebuilt compressors...some guys claiming the only good ones come from john deere IIRC...so an upgraded unit with a warranty might not be a bad idea...usually a system that slowly loses a charge doesnt lose that much oil...if its in a crash and blows apart then it'll take a lot of oil with it....think what your engine compartment would look like if sprayed with 10oz of oil...standard procedure was to throw in a can of oil charge just to be safe...unfortunately there are two ways to fix a vehicle...the right way, and the way the customer is willing to pay you to do it...

[Davidf]

Put me in the camp of seal failure on a rebuilt A6 compressor. Beginning of this summer, I rebuilt the entire A/C system on my '71 including having the A6 compressor checked/resealed. This past weekend, the A/C did not cool (after truck sat for a good two weeks unused). Using my Halogen leak detector I went straight for the front of compressor and sure enough, the seal was leaking. I topped off the refrigerant, but will be ordering a Pro6Ten compressor soon...originality does not matter on this truck.

So, to the OP. Don't waste money on the A6 compressor, go ahead and replace it with a modern design like the Pro6Ten (or whatever you choose).

[Katrina/10]

Originally Posted by MARKDTN

In no way trying to argue with Hugger. But here is a little supplemental info on refrigerants so you may have a better understanding- but don't just take my word for it-do some research yourself. I believe Freeze12 has been discontinued now anyway. Even so, I would be very cautious with this-and any blend. The short version is either use R12 or R134.

The long version is this:
1-Freeze 12 is a mixture of R134 and another Freon. The reason it exists was really for conversions on R12 systems using existing parts. It was thought to be more compatible with the existing oil in an R12 system. In many cases it is OK, but if there is any residual moisture from a system left open for a long times and not replacing the dryer and compressor and flushing the evaporator and condenser, there is a risk of failure.

2-many blends (not freeze 12) contain butane. Do you really want butane at high pressure in your engine compartment?

3-Many blends contain molecules of radically different size-think BBs and Ping-Pong balls. When you need to add some charge at some point all the "BBs" are gone and the "ping pong balls" remain. You cannot get a balanced charge without blowing the whole charge and starting over and the remaining mixture can be caustic to hoses and seals or cause pressure issues.

I see no reason at this stage to use anything other than R12 or R134. Supplies of both are plentiful and relatively inexpensive. A/C is not a place to go cheap IMHO. I know there are people with success with all of the above products, but you will also find a lot of failures. Why chance it when the original refrigerants are out there and work well? You may spend more money and time than just do it right the first time. To me I will put R12 back in vehicles originally equipped with it.

To the OP. Sounds like you are on the right track. You do need the right amount of the right oil. You could guess how much is left and how much to add, but you are probably better off long term to just bite the bullet and get the old out and add the correct amount especially if the system was open for a long time.

How is R12 plentiful and cheap? I haven't seen any in my area in a long time. I have heard of people selling it on ebay for 30 or 40 dollars a can.

[kennygs72]

Are the Pro6Ten comp compatible for r12?, Every auto part web sites just shows them for 134A?

[Davidf]

Good question. Call Old Air Products and find out...I will for sure now that you mention it. But, I don't think it matters what type of refrigerant you use just so long as you use a compatible oil of proper viscosity for the compressor.

For Katrina/10: R12 is available, but certainly not cheap. You wont find it out on the shelves at your FLAP. But, many have it behind the counter and will sell it to anyone who has a license/certification to service automotive a/c systems.

[F.A.A.benny]

Originally Posted by kennygs72

Are the Pro6Ten comp compatible for r12?, Every auto part web sites just shows them for 134A?

You just have to change the oil in it. I sold one to a guy who was putting it in his Olds 442. He changed oil and no problems

[F.A.A.benny]

Originally Posted by ssuesens

So I stopped by my local ''Old School' ac shop this afternoon. He looked over the entire system and said all looked ok. He looked at my rebuilt ac compressor and suggested I swap it out for a 10 piston aluminum A6 style compressor. For $230 he said it would out perform any A6 model with less weight, noise and power draw. He will put in the mineral oil, I will install the compressor, and then he will draw vacuum and fill the system with my R12 Freon. All this for $35. Hopefully I will have cold air by wed or Thurs!

Whats the name of the "old School" ac shop? $230 for a pro6ten? At that price he is selling it at barely above his cost. Seems highly odd that he would only want to make a few bucks on it when it is normally sold for $370

[Davidf]

Yes, do tell where to get a Pro6Ten for less than the $345 that Old Air Products wants.

[F.A.A.benny]

Originally Posted by Davidf

Yes, do tell where to get a Pro6Ten for less than the $345 that Old Air Products wants.

I thought my price was good at $300. But $230 is a steal of deal!

[MARKDTN]

Originally Posted by Katrina/10

How is R12 plentiful and cheap? I haven't seen any in my area in a long time. I have heard of people selling it on ebay for 30 or 40 dollars a can.

Plentiful means there is supply. There is. If there is still mainly cans after 10 pages on Ebay I call that plentiful.

If you look around you can do better, Ebay prices right now look to be more like $30 a can(but even if you can't then 4 cans is $160). I had a 30# cylinder that took me over 10 years to sell at $250. Looks like that is still the bottom end price on Ebay. To get a deal you may need to take the class to get certified. It used to be like $20 or so. Then you can buy a 30# cylinder for less than $10/pound, sell to your friends at $20/pound. You get yours free, they get a deal. Win-Win.

R134 is $6.88 a can at WalMart so the same 4 cans is $27.50. You save $92.50, but then you have to buy the conversion fittings, new O-rings, and have your POA adjusted or convert to a cycling kit. All of that eats your savings-and unless you change your condenser it won't cool like R12.

Do what you want, all of this is my opinion.