Vintage Air Question

ChuckG · Jun 17, 2017

The ongoing saga of "issues" with the VA system in my 37 coupe goes on. I know that this problem is not on my Tri-Five, but I'm hoping to get some answers here.

My buddy with the professional gauges has been unable to make it over to the house to help me out, so the car is just sitting.

I was advised to put a new dryer in the system. I bought one, identical to the one in the car.

I removed the old dryer and plugged the IN and OUT lines to it.

Turned the old dryer upside down... and hardly any oil came out. I might have gotten a drop or two... that's it.

I can't get a consistent answer. Some say to add 2 oz. to the dryer directly. That new PAG oil would have to be added through the IN or OUT fitting.

2 oz seems like a lot... that would be 2 shot glasses full.

Any advice?

The system has a Sanden 508 compressor, which I have learned has 5 oz of oil from the factory , and that is meant to lubricate the entire system when new.

57-Z06 · Jun 17, 2017

First, I'm surely no expert when it comes to A/C service. However, if this were my car, I'd simply install the new dryer, evacuate the system for at least an hour or two, check for leaks, and charge it up.

I've gone through this same type of process a couple times in my life and have not added oil with the recharge.

ChuckG · Jun 17, 2017

57-Z06 said:
First, I'm surely no expert when it comes to A/C service. However, if this were my car, I'd simply install the new dryer, evacuate the system for at least an hour or two, check for leaks, and charge it up.

I've gone through this same type of process a couple times in my life and have not added oil with the recharge.

Thank you for the input.

I know nothing about AC systems, which is what has me frustrated. I'm a better than average shadetree mechanic...

I have done what you describe in the past... and I never added oil.

That being said, because I have had numerous leaks in the past, some tell me that you lose PAG oil when you lose R134.. and it should be replenished.

Some also say that if you put too much PAG oil in, you can "hydraulic" the compressor... The other side of that coin is if you have too little PAG oil, you can burn up the compressor.

There is no way (that I know of) to check the oil in the compressor unless you remove it, take out the plug, turn it over... and measure what comes out....

acardon · Jun 17, 2017

ChuckG said:
That being said,[/B] because I have had numerous leaks in the past,[/B] some tell me that you lose PAG oil when you lose R134.. and it should be replenished.

Have you added any oil in the past?

There is no way (that I know of) to check the oil in the compressor unless you remove it, take out the plug, turn it over... and measure what comes out....

And flush the rest of the system. It may be best to start over.

cruzn57 · Jun 17, 2017

the dryer

has desiccant inside it, its there to absorb water, but does hold oil, as well.
how much? I've never checked,
if it were mine.... I would add 1-2 oz of oil, thru the charging port,
not directly into the dryer,
http://www.autotoolworld.com/FJC-27...pPKBRCGwrSpqK7Y5jcSJACHYbWYsohv9lPakcOLAzWisMwgUdMw_KupHmMGMkyGB8-npRoCrePw_wcB

this is what I use,

always spin the comp by hand after adding oil to assure it is NOT hyd locked !

ChuckG · Jun 17, 2017

acardon said:
Have you added any oil in the past?

And flush the rest of the system. It may be best to start over.

I have never added oil.

I was relying on my buddy for help and advice, but he has been unavailable this entire week. He has all the tools, including a vacuum pump, etc.

ChuckG · Jun 17, 2017

cruzn57 said:
has desiccant inside it, its there to absorb water, but does hold oil, as well.
how much? I've never checked,
if it were mine.... I would add 1-2 oz of oil, thru the charging port,
not directly into the dryer,
http://www.autotoolworld.com/FJC-27...pPKBRCGwrSpqK7Y5jcSJACHYbWYsohv9lPakcOLAzWisMwgUdMw_KupHmMGMkyGB8-npRoCrePw_wcB

this is what I use,

always spin the comp by hand after adding oil to assure it is NOT hyd locked !

Interesting. Thank you. I have never seen that tool, and it certainly makes more sense to add oil at the charging port... and not pour it directly into the dryer.

acardon · Jun 17, 2017

ChuckG said:
Interesting. Thank you. I have never seen that tool, and it certainly makes more sense to add oil at the charging port... and not pour it directly into the dryer.

The tool is handy for adding oil to a system under pressure, but you don't need it to add oil if the system is open and you have to evacuate it.

topdog · Jun 17, 2017

1. Vintage air comes with oil in the compressor
2. The modern evacuate and fill systems reuse the Freon in the system
3. Condition over looked is over charging the vintage air system or not fully evacuating
4. the specifications on a vintage air system is different than OEM systems
5. No need for added oil in system if you find a garage with modern equipment and he will program the machine to vintage air specs.
6. I learned the hard way and for 100 bucks my system is now working with very cold air
The modern equipment adds the proper amount of oil if needed.

I went cheap at first and just wasted a lot of money. It only takes an hour to do it right

hotrodg726 · Jun 18, 2017

I would not initially add any oil . I would evacuate the system for 1.5 hrs. then charge the system to get it running . measure the compressor body temperature. if it is more than 120 degrees add 1 OZ oil and recheck temp. if it is at 120 call it done.if it is above 120 then add another OZ . then recheck compressor body temp

ChuckG · Jun 18, 2017

Thanks to all for the input.

My life took a turn for the better yesterday...

I drove the 56 Chevy to a club event at a local indoor mall yesterday where we had 40-50 cars on display for the kickoff of the new CARS movie. I gathered a lot of useful information.

#1. My buddy with all of his AC stuff is dropping it off with me this morning. As I previously posted, he's been busy this past week.

#2. In a conversation with another club member yesterday, he told me that he has a freon sniffer.

I'm welcome to use it anytime.

#3. Consensus is not to add any PAG oil initially.

So, today being Father's Day.... I probably won't mess with it, but will hit it next week and get the system up and running again..

Then, I'll re-evaluate things. If I'm still having problems, I'm going to take it to an AC pro, and again, in conversations yesterday, I got the names of two small local shops who have done work on VA systems for guys in my Cruisers Club.

Regarding Hotrodg726's comment, are you measuring the compressor temp with an IR gun?

hotrodg726 · Jun 18, 2017

ChuckG said:
Thanks to all for the input.

My life took a turn for the better yesterday... I drove the 56 Chevy to a club event at a local indoor mall yesterday where we had 40-50 cars on display for the kickoff of the new CARS movie. I gathered a lot of useful information.

#1. My buddy with all of his AC stuff is dropping it off with me this morning. As I previously posted, he's been busy this past week.

#2. In a conversation with another club member yesterday, he told me that he has a freon sniffer. I'm welcome to use it anytime.

#3. Consensus is not to add any PAG oil initially.

So, today being Father's Day.... I probably won't mess with it, but will hit it next week and get the system up and running again..

Then, I'll re-evaluate things. If I'm still having problems, I'm going to take it to an AC pro, and again, in conversations yesterday, I got the names of two small local shops who have done work on VA systems for guys in my Cruisers Club.

Regarding Hotrodg726's comment, are you measuring the compressor temp with an IR gun?

you can use an IR gun if you want but I use a touch probe thermometer.

ChuckG · Jun 19, 2017

hotrodg726 said:
you can use an IR gun if you want but I use a touch probe thermometer.

Good tip. Thank you.

My friend with the AC equipment is coming over to the house Wednesday afternoon to give me a hand. :tu

He dropped off all of his "stuff" this morning. Since he volunteered to help, I'm not touching anything till he gets here.

In the meantime, I'm making a call tomorrow, and borrowing the sniffer so I'll have it for Wed. afternoon.

We'll hopefully have it up and running again. From there, I'll re-evaluate and if I'm still having problems, I'm going to take it to a pro.

You definitely need AC in Florida... especially in the heat of the summer.

ChuckG · Jun 22, 2017

Success!!

I had replaced all the O rings and installed 2 new Schrader valves. Had a brand new dryer...

Added 2 oz of PAG oil to the compressor.

Drew a vacuum on the system... -30 mmHg initially, shut off the vacuum pump, and let it sit for 15-20 minutes. It held steady on the gauge at -30mmHg, so there were no obvious or large leaks.

Then, pulled a vacuum of 30 mmHg for 30-40 minutes with the pump running. Put in one 12 oz can of R134 before starting the car.

Fired it up... with all the gauges attached, and added another 12 oz can. That's a total of 24 oz... or 1.5 lbs.

The thermometer in the duct inside was at 41*.

The gauge showed between 15 and 20 PSI on the low side... even when the idle was increased.

We debated adding more... but decided against it...

I had borrowed a freon sniffer, but I'm not sure it was working. We couldn't get it to BEEP even holding it over a recently opened can of R134... so ???

Forgot to measure the temp of the compressor... My mistake...

So, I'm happy.

The real proof of my success will be to see if the system can KEEP a charge, and not slowly lose R134 over the next month or so.

Thanks to all for your help and advice. Here's a pic of my buddy Paul helping me out.

hotrodg726 · Jun 22, 2017

get that compressor temp. it is important for the life of the compressor.

roger1 · Jun 22, 2017

hotrodg726 said:
I would not initially add any oil . I would evacuate the system for 1.5 hrs. then charge the system to get it running . measure the compressor body temperature. if it is more than 120 degrees add 1 OZ oil and recheck temp. if it is at 120 call it done.if it is above 120 then add another OZ . then recheck compressor body temp

John, I thought a good number was more like 130 - 135.
Do you know of any resources out there with documentation on this?
I wonder if the nominal number is any different for R12 or R134a too.
I'd like to read more on this subject but haven't been able to find anything.

hotrodg726 · Jun 22, 2017

roger1 said:
John, I thought a good number was more like 130 - 135.
Do you know of any resources out there with documentation on this?
I wonder if the nominal number is any different for R12 or R134a too.
I'd like to read more on this subject but haven't been able to find anything.

I am just going from what I have been tought from old guy's over the years.
you need some temp to keep the oil in suspension for lube.

ChuckG · Jun 23, 2017

Checked this morning. Putting out 44* air at the ducts.

Checked several areas along the top of the compressor, and I'm getting 170* readings.

So..........what to do?

roger1 · Jun 23, 2017

What are your high and low side pressures at 1500 rpm and inside controls and fan set to maximum? Good to blow a box fan into the front radiator area too to keep hot air from recirculating around through the condenser and radiator.

It would also be good to shoot temperatures of the inlet and outlet lines of your condenser.

I think it's important to know your pressures before recommending adding oil.
But your compressor case is too hot.

Btw, I wanted to be able to get more accurate temperatures than a laser infrared gun will give you. But, I didn't want to spend a bunch of money for test equipment either.
Ended up going with an inexpensive DMM and temperature probe:

http://www.mcmelectronics.com/product/TENMA-72-7725-/72-7725

http://www.mcmelectronics.com/product/72-8364

ChuckG · Jun 23, 2017

roger1 said:
What are your high and low side pressures at 1500 rpm and inside controls and fan set to maximum? Good to blow a box fan into the front radiator area too to keep hot air from recirculating around through the condenser and radiator.

It would also be good to shoot temperatures of the inlet and outlet lines of your condenser.

I think it's important to know your pressures before recommending adding oil.
But your compressor case is too hot.

Btw, I wanted to be able to get more accurate temperatures than a laser infrared gun will give you. But, I didn't want to spend a bunch of money for test equipment either.
Ended up going with an inexpensive DMM and temperature probe:

http://www.mcmelectronics.com/product/TENMA-72-7725-/72-7725

http://www.mcmelectronics.com/product/72-8364

I cannot answer your questions, as I no longer have the equipment here.

I simply used the duct probe thermometer over the top of the case. I might add that the water temp was 200*, and the compressor is mounted closely above the intake manifold, and close to the thermostat housing and upper radiator hose.

The ambient temp under the hood is pretty hot.

Vintage Air Question

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