pfsantos

iTrader: (1)

I've been researching info on our A/C systems. I've managed to find a few bits of info such as some of our compressors are Sanden SD-708, and used (in 86-88) a factory fill of 25-26oz of R-12.

My current system has no pressure. It hasn't been used at least 12 years (since I've owned it). Can I check for leaks using a vacuum gauge? Is 25inHg reasonable? How can I find out how much oil (if any) is left in the system? I've read (in the Sanden site) you have to run the compressor a few minutes, and then take off the oil fill, but this doesn't work when you have no pressure to run the compressor. I found a spec. for oil quantity per Sanden, but that was for the equivalent R134a compressor.

I want to use one of those R-12 alternatives (I already have the kit), but want to make sure the system has the proper amount of oil.

jackhild59

iTrader: (7)

Ok, I can help.


"R-12 alternatives (I already have the kit)" sounds bad, but we will come back to that.

You likely have dry seals around the compressor shaft. The other orings are likely ok, for now. They will probably relube when you run the compressor and will likely seal pretty well. Pulling a vacuum on the system before this will be an exercise in futility and only confirm the dry compressor seals.

Here is what I would do. I would change the dryer and put new orings in the dryer fittings. I would then charge the system with about 4 oz of ESTER oil; do not ever ever put PAG oils in a retrofit.

Give the system a 1/4 charge enough to make it run, enough to short cycle the compressor rapidly, every say 20-30 seconds. let it run for 10 min. or so. Shut it down then use a key or pick to hold open the Schroeder valve and let all the gas out, down to atmospheric.

Repeat the 1/4 charge, the 10 min short cycle run, shut down and gas out to 1 atm.

Do it again, short cycle, for 10 min, shut down, then gas out one more time.

You have now performed the equivalent of a triple rinse. This is the gold standard for removing contaminations. The gas that is in the system at 1 atm is now quite dry and very very close to 100% refrigerant. You haven't sucked any air or water vapor into the system through the compressor seal. The brand new dryer is still dry. In fact, at this point, the compressor shaft seal may be re-lubed and doing a fair job of sealing.

Now charge the system and use it. If it leaks down, recharge. You might do this a couple of times but everything is quite likely to work out.

You also haven't violated USEPA laws, because you are in CANADA!

pfsantos

iTrader: (1)

Very informative. Now what about my fears about having the proper oil quantity? The 'kit' (Red Tek) I purchased has an oil analyzer, which supposedly tells you whether you have enough oil. You mentioned 4oz of Ester oil. The same maker has an "oil charge" can (I believe it's an 8oz can) - so I can just add half a can of the stuff?

Also, this kit has a gauge. I've read to charge to 35-40psi on the low side...is this while the compressor is active (clutch engaged)? Because as it shuts off, I think the system is equalizing and the gauge starts going up.

I've been helping my neighbour for the second time (different car) with this product, and am getting good practice for my car and learning stuff too!

Thanks again for your help thus far.

jackhild59

iTrader: (7)

Now lets talk about the 'alternative refrigerant' you purchased. Red Tek. This is hydrocarbon based. If you use this, you are a fool, a moron and have a death wish.

http://www.imcool.com/articles/airco...erant_Fire.php


Here is a link to the Australian 'Pioneer' (aka Moron) that has been pushing the HC industry for years. He was doing a 'safety' demonstration to prove just how safe HC's could be to industry observers. It was a simulation of an evaporator leak. He was prosecuted, convicted and forced to retire from his university position.

http://www.vasa.org.au/pdf/memberlib...aine-cross.pdf

This is the caliber of 'research' that the moron put into the HC industry.
http://www.youtube.com/watch?v=DjtowzVzl_4

If you were in a hot weather location I would also tell you that the system won't work worth a damn with the HC, but it probably will work just fine for the ***** Canadian heat. Don't you guys have 2 seasons, Winter and July?

We will be 34*C in Dallas today. This is Spring. We know A/C


Also, if you are bound and determined to HC, I will sell you some that I have left over from when I used to think this was the greatest thing. I have tested, tried, retried, blended my own and the **** just doesn't work well enough to screw with it, but you will have to come to Texas to get it, cause I am not shipping flammable material across international borders.

Face it, the stuff just isn't worth screwing with. Why mess with the HC's when Freeze12 works so very, very well?

jackhild59

iTrader: (7)

Recommended stongly by those in the 7 club that really really need A/C:

http://search.ebay.com/search/search...+12&category0=

HAILERS

I'm not really into a/c, but at one time I looked at this site: http://www.sanden.com/support/index.html

And if memory serves, the manual there showed how much oil was supposed to be in the compressor. It's been a while.

jackhild59

iTrader: (7)

Good find. Typical assumptions are that +/- 40-50% of the existing oil is found in the compressor and the 40-50% is found in the dryer. Any remaining elsewhere is less than 10% and is coating the interior of the hoses, the pipes, heat exchangers etc. The oil circulates along with the refrigerant when the system is running.

Of course, in the case of a leak, oil is lost. No one knows how much has been lost, ever. So if the chart says we need 6 oz, we assume that when we replace the dryer, we need 3oz added. If we replace the compressor with a new one, we add 3 oz.

This is yet another reason to replace the dryer. We get closer to a known quantity of oil in the system so the oil charge added is closer to correct. We can never really know exactly unless the system is either new or flushed, but we can get close. A little too much oil is not bad, too little oil is bad. How much variance? I don't want any more than an extra oz.

Example:
When I replaced my damaged compressor with a 'new' used compressor bought on the board, I drained the compressor by turning it upside down, and turning the shaft until no more oil drained out. I now assumed that the compressor was close to empty. With the new dryer as well, I added 6 oz of Mineral oil, because I use R12. I put half in the dryer and half in the compressor for initial startup. Been working great for 2 summers, going into the third summer.

pfsantos

iTrader: (1)

Hey, you were so nice in your other post...what happened?

Well, I don't have a death wish, even though I know I'll be putting flammable stuff under pressure in my system. While we're talking ****, why don't you pull some strings and have my local auto store carry some R-12 on the ******* shelf.
Because that's where I got the Red Tek.

You see, when faced with a simple DIY system with no retrofitting required and having your AC system dead, versus spending a lot of money, it's kind of tempting to go with the stuff readily available and compromise on other aspects. Maybe I do have a death wish.

BTW, I did read about the Australian AC fire that burned the Porsche.

I was on the Sanden site, but couldn't find any info on the original SD-708 compressor for R-12. I saw the lubricant capacity for the equivalent R134a compressor, but am not sure if the spec. would be the same.

Last question (for this post) - does the lubricant "disappear" with the freon (i.e. should I add the full spec. of oil)?

edit: I'm reading your latest post, and you're answering much of the above. I respect your knowledge, and can get your points without the insults (it does nothing for professionalism).

pfsantos

iTrader: (1)

Forgot to ask...what's this freeze 12 made of, and do I need the test (EPA) that I've read about?

jackhild59

iTrader: (7)

The Posche fire was in Wichita KS, the professor who burned himself and 14 others was in Australia.

I am still nice and very helpful, just a little prickly. I didn't insult you, I warned you. Ok the ***** comment was uncalled for, but since you don't control the Canadian weather anymore than I control the Texas weather, it's kinda like saying Texas gets hotter than hell. BTW, I work for a Canadian company and we love it when they visit down here in the summer. One VP actually thought we didn't need A/c in company cars, so we invited him to Houston in August. We didn't run the A/C in Houston drive time traffic. He never came back and the issue was dropped.

Look, I used to argue pro HC on the auto air conditioning boards. I also custom blended my own HC refrigerants. I worshiped at the alter of HC cooling. Then the professor blew himself up and I met Lois Ott. I also know Earnie from that article. I hang around with lots of Porsche 928 guys. They all have abandoned the HCs due to this incident. Before that day, HC's were all the rage in the 928 community.

Remember, the LIQUID lines are right behind that bumper. With your HC's that will be mostly LIQUID PROPANE. You can use HC's, but you should plan in advance to never ever have any front end collisions. That should fix it.

And teh HC's don't even work worth a damn.

jackhild59

iTrader: (7)

No, you don't. Freeze12 is 80% R134a and 20% R142b. The 142a is for reducing the head pressure and also carries the mineral oil through the system. When using Freeze12 I prefer to add Ester oil to replace the mineral oil. Ester works with all auto refrigerants.

pfsantos

iTrader: (1)

I see what you're saying. HC's under high pressure are far from ideal.

Having said that, it must be mentioned that the Porsche fire was due to a line being chaffed by another part, wich caused the gas to escape and ignite. Also, the accident the professor had was an experiment where he ignited a can of this gas inside a closed passenger compartment with a match. As with anything possibly dangerous, I think one can always take certain precautions to minimize the chances of accidents.

Maybe I took the easy path, with the Red Tek being on the shelf, versus ordering the Freeze 12. I hadn't seen my system run, and wanted to try anything in the short term.

The Red Tek kit I bought last month is pretty nice, with an installation hose with built-in gauge. I installed a can this afternoon just to get the compressor going. I will admit I was a bit scared when the low fitting leaked for a second with the engine running. I shut down the ignition immediately.

Hopefully this thread along with the archived one will help people see a few viewpoints.

I'm definitely not sold on HC refrigerants by any means, and did read about them not working well in very hot weather. I guess availability (Red Tek is sold here locally at most major car nut places) played a key part in my choice.

BTW, here in Toronto we say there are two seasons: Winter and Construction. We do have extremely hot days in the summer, but it's usually only a few at a time.

jackhild59

iTrader: (7)

That situation was NOT an experiment. The 'perfesser' had been claiming safety for years, stating the amount of HC that could be safely released into the car interior. He had even done some demos where he had released some HC and ignited it. The resulting flash was kinda like lighting a fart, funny and no one got hurt. This last demo was a put up or shut up moment, the calling out of all his years of writing and speaking publicly about the safety of HC's. The amounts that he had been claiming was safe to release in the interior is the amount that was sprayed in. The resulting damage and injuries cost him his status, his job, his freedom and his health.

BTW, propane is heavier than air. It settles into low spots and does not dissipate. Propane is not used for Marine use because any leak does not dissipate, it settles and concentrates. An evaporator leak can cause the interior of the car to fill up with concentrated propane. Open the door and you get some mixing of air and propane. Start the car, something sparks. The demo was perfect demo of the potential hazard.

Now, think about having a little fender-bender dust up in your HC charged 7. You bash into the back of another motorist at say 10-15 mph. You are a little shocked and dazed. Do you really want to think about being in that situation and having HC's igniting under the hood?

They put oderant into the HC so you can tell if it is leaking. The one I used put a nice pine evergreen scent. I asked them why they didn't just use the mercapitan used in the propane industry. They told me that the scent scared people, but the evergreen scent didn't. I ran the stuff in my 7 for a couple of months. It didn't' cool worth a damn, I couldn't get the pressures or performance right. Interestingly, the entire time, I could smell evergreens. I didn't have any leaks, but I could smell evergreens. I put it in my wifes Celica Convertible with similar results.

I am 100% R12 now.

Good Luck with the stuff, I've been down that road.

Edit:

I just checked, you are 17*C today, we are 34*C today.