How can I tell what refrigerant I have in my system
 

I am in getting ready to replace the a/c compressor and need to figure out if I have r-12 or r-134. Is there a way to figure it out?

What would be the year model of this car?

134 has different fittings to add freon. The hose to add r12 wont connect to a 134 system. And yes, what type and year of car do you have? 66 Pontiac or 2001 Rolls Royce. :)

I've got R134 fittings and yet it's filled with R12.

sorry, 1980 300d

a refrigeration analysis is the only way to be SURE, but if you have 134 stickers on the car, and you have 134 fittings on the car, it's a good guess that 134 is in there.
if you have the original 1/4" flare fittings on the car, it's a good bet that 12 is still in there.

On my CD the lower one was not changed.

My wagon came to me with one of each type fittings.I Called every so called A/C shop within 50 miles and none had the ability to identify the refrigerant ! Most were not even aware that there was such a tester. Called an old friend who did alot of A/C work, he said put in "Freeze12"which i did and it has been working very well for over a year.He said it is compatable with both gasses and either type of oil.Not suggesting that you do the same but it worked for me. FLAME SHIELD ENABLED!!!
Don

That's probably because the guy did the conversion himself and just put the adapter on the low pressure side.

If you have a R-134a on your low pressure side I'd bet that's what's in there.

I'm fairly certain the new stuff is in there, that lower line is quite costly.

nahh, call phil, he's got GREAT prices on the lines!

I don't believe he is referring to his refrigerant line needing to be changed but that the R-134a adapter has been put on the low pressure side but not on the high pressure side.

At least that's how I read it.

It was r12 in the system, went back and looked at the records when the a/c system was redone. I disconnected the compressor and there was no freon in it, which must be the reason the compressor froze up. At first I thought it was just the clutch that went out, but the compressor when turned manually grinds. The o-ring on the back had a big gouge, so I assume that is where the leak was. Need to put a vacuum on it once I get the new compressor installed.

I am thinking the freon as well as oil leaked out and caused the clutch to fail. Any thoughts?

Sounds likely. Oil gone probably caused compressor failure which in turn caused clutch to fail. But now, the point is, unfortunately, moot.

The ONLY way to know for sure is with the use of a Refrigerant Identifier. Most anyone who does any volume of auto refrigeration work will have one. Fittiings installed mean nothing, in spite of the fact that Federal Law requires that the appropriate fitting for the refrigerant used be present. Too many rogue conversions out there for this to be reliable.

Call your local shop and ask if they have a Refrigerant Identifier.

TEX599 , are you going to flush the system to clean out any potential burned oil caused by the compressor failing ?

yeah, this is a good point.
since there is no freon in there now anyway, and your compressor is grinding, thus debris is in the system, at a minimum, you need to reverse flush your lines, and the condenser using an a/c flush agent, and dry nitrogen. get a new reciever, and if it were me, I'd also convert the expansion valve into a flush tool to flush out the evaporator as well, then install a new expansion valve. that way, you can use the PROPER oil for the refrigerant you choose to install, and charge it up right!

If you did that with the expansion valve you would be following the Mercedes AC Factory Shop Manual.... always a safe plan...
The other stuff is of course right on the money also for longevity.
If this is the R4 compressor the manual says the manifold needs to be renewed. Seems it can not be flushed properly in case of compressor failure.

It is the R4 compressor and I do plan to replace dryer, was not sure about the expansion valve. System was completely rebuilt in 2008 with new everything. I was going to have the shop that will fill the system do the flush. How hard is it to flush, I know you can by the flush at the parts store? If I do the flush, can I also fill the system with R134a? Anyone have experience on this?

flush is a cleaning prep step for the new compressor.
it's a small step, that requires completely blowing out ALL residue/oil/flush chemical from the lines with dry nitrogen.
once this is complete, all the o-rings in the car need to be replaced, then the oil, and compressor and reciever get installed, and pressureized with nitrogen to verify it's leak free. then that needs to be removed, and the system totally evacuated and THEN the system gets charged with refrigerant.
R12 would be my choice of refrigerant though.

You mean this:


http://i711.photobucket.com/albums/w...f/SANY0049.jpg

Clean that sucker out...

Pic shows 134a valve with the red top on it and the r12 valve on the top tube.

If you have r12 for sure I'd stick with it. Consensus seems to be that R4 compressors are marginal running with r12 pressures and r134a operating pressures are higher. Oil is another thing. R4's may not agree with the oils r134a require plus r134a will leak out of the old hoses faster than r12.



If your compressor threw debris through the system you may be in for a job. Not an impossible job, not really that hard, just kind of tedious.

Yes, that one.
Someone was going to send me an old one and me cut it apart to see if we could determine if there was some screen hidden in there which can not be cleaned properly... thus the instructions in the MB AC manual to REPLACE IT ....
The impression that R4 running R12 were marginal only comes from you hanging around a group of people who have cars with 200k PLUS miles on them and often cars which they have no idea what kind of idiot serviced them in the decades before they owned them.
MILLIONS of R4's worked great with R12 ....
I do not know if ' TEX' is from Texas... but if he is then R12 is the highly recommended refrigerant running Castrol premium cold flow oil of the proper amount. Cleaning the system properly is of extreme importance if you want it to last... and cool...

VStech, where did the super AC sticky thread go ? Are you condensing and finalizing it now... since you have plenty of time with no huge time sensitive projects in your life..like getting rid of 75 cars which accidentally followed you home over the years....
It is still hot in Texas....LOL

I unstuck it for the fall.
I'll clean it up and make a nice first post and send it back up top in the spring.
of course it's still hot in TX... does it EVER get really cooled off in TX?

Maybe this is why they said replace it:

Bushehr reactor #6 inlet - YouTube

This is mine taken off a functioning system that had been converted to 134a. Compressor clutch went bad.

I ran a wire through both tubes and didn't feel a filter.

Here's my receiver:

http://i711.photobucket.com/albums/w...f/IMG_2266.jpg

You'll want to replace it as well.

Perhaps "marginal" was too strong a term but the overall design makes them oil charge sensitive because they have no sump to store oil.

I would be scared to run another one on 134a.

UGH!
that's just nasty!
imagine all those scabs flaking off with fresh oil and refrigerant, and flowing through your system!:eek:

Most of it looked like corrosion although I think I saw some particulate :confused:

120 days in row over 90 degrees
87 over 100 days . Record by about 20 days.
no rain for four months....
Hottest average temperature for the summer Ever ... 150 years of recording...
Aug hottest month on record.
I am in the county which had the 1500 homes burn on 35,000 acres...

It just seems like TEX599 might could have done some research in that thread if it were available... and some people wait till reasonable weather to tackle their AC systems ....

It's also a safety issue. The defroster works extremely well when the AC is working.

the thread is still there, just not stuck.
anybody can bump it up to the top. I figured it was not getting much attention. heh, maybe I should post a poll to stick it or not... that didn't sound right...

Evidence my brain is fried... I knew that and yet had to read it four times to understand what you were saying..

for others not intimate with your dash workings...

When you turn on the Defroster.... your car turns on the AC also ( if it is functional )... it routes both fresh air and recirculated cabin air through the AC cooling fins first... dropping out the moisture.... then to the heating coils of the heater and is directed to the inside of the windshield to keep it from fogging over.

Thanks guys, yes I am in Texas and it is still hot. I appreciate all of the information you guys are saying. Where is this sticky you speak of, can't find it. A link would be great. I am still working on the a/c, not in a rush this is a 5th car, but want to do it right. Was thinking r12, but only found one shop and he wanted $9.50 an ounce. I am waiting on the new drier to arrive and then will be ready to move forward.

Also found a AC Parts shop that can rebuild the old compressor for $149, which was an AC/Delco. The one I bought is a Murray/Four Seasons, this one I paid $190 for. Is the AC Delco better or does it matter?

Are you saying you already purchased a reman? If so I would just go with it.

There is some info on how the compressor should be oriented. There is an "X" on the case that needs to be either up or down and I think it's possible to get one that will mount upside down.

Plenty of info here if you search R4.

$9.50 an ounce. Ouch! At those prices you could "tool up" and do it yourself with help from the forum. That way you could service it yourself in the future with R12 from ebay or somewhere... I guess it depends on how much you like getting dirty :D

Do you know where your expansion valve is? You'll need to pull it and at least inspect it and flush your evaporator plus all the hoses.

I just re-did my entire system and it wasn't near as bad as I had envisioned ;)

Tex599, Where in Texas are you ? You might get lucky if people know that....

... for nearly $160 a pound (9.60/oz x 16...) I'd drive to YOU and fix your car with R12!!! that's $4800 per tank! even at the highest price they charged for 12, it was only $1500 for a 30lb tank... WOW. the current price for R12 in my refrigeration supply house is $488 for a 30lb tank... 1000% markup... cool.
wow what a rip off! unless that's ALL he charges for, no labor, no parts...

Live in Fort Worth, TX, so if anyone knows somebody that can do R12 at a reasonable rate let me know.

Expansion valve, behind the glove box right?

1980sd, how did you flush your system?

Not the best method but it worked for me:


Quest/Clean and flush aerosol (CA-1) | A/C System Cleaner | AutoZone.com

Smelled like some sort of citrus stuff. I replaced everything but my evaporator but I used this stuff to flush it out. It has a tube with a rubber stopper for shooting it into the lines. I pretty much just followed the directions on the can. I hooked a hose up to the line leaving the evaporator so I could see what was coming out and I gathered a lot of funk! You'll need compressed air as well but my little nail-gun compressor worked fine.

The best method would be to blow it out with some inert gas with a "pulse-gun" to keep moisture out of the system though...

You'll need to do your condenser as well as your hoses so just get used to the idea that everything needs to be disconnected. It's not that bad once you get started.

My expansion valve was behind my instrument cluster but yours may be behind the glove box. I'd consider that a plus because you can leak-test without figuring a work-around for having no instruments.

It'll need to come out and be replaced as well.

I have little AC experience but managed to get mine working using all backyard/DIY methods other than charging the system. I paid someone to do that.

Saving $$ is secondary to the satisfaction I get from figuring stuff out and tinkering with cars.

Good luck and don't get in a big hurry! Lots of good resources here!

Ok.. should have done this way back..... TEX599... just look at my signature for references. If you read all of each of them ( not chain elongation ) you will be way ahead of the game...

This first one is the authorization to use pressure for leak checking and vent the nitrogen/r22...just as reference...

''Releases of CFCs or HCFCs that are not used as refrigerants. For instance, mixtures of nitrogen and R-22 that are used as holding charges or as leak test gases may be released.''
from:Complying With The Section 608 Refrigerant Recycling Rule | Ozone Layer Protection - Regulatory Programs | US EPA

''Technicians are required to pass an EPA-approved test given by an EPA-approved certifying organization to become certified under the mandatory program. Section 608 Technician Certification credentials do not expire.''
from: Complying With The Section 608 Refrigerant Recycling Rule | Ozone Layer Protection - Regulatory Programs | US EPA

This is an open book test.
It does not cost much.
It can be done over the internet including paying for it.

it allows you to buy R12 at many places that you do not even know carry it... in fact many times the ' first day on the job counter help' do not know they have it in stock... if you have your license in your pocket and ask the manager ' presto' !!!!! But typically ebay or CList is cheapest way to get it... I paid $18 for 12 oz of R134a a month ago ( for my Ford ) ... bummer, but means the old price difference is pretty small now...

Even if you are going to have someone else do it...and there is no sin in that... this is tedious work.... if you do the research you will know what to ask them...and as they answer you might find you know more ( about the CORRECT way ) than they do and you need to keep looking for a good shop.... of course that does not keep them from telling you the right answer and then not doing it properly.... but if they do not KNOW the right way.. they sure can not do a good job...

Have you done it? Is it the "Type I" certification? I've looked at the site and never could figure out how to do the online test...

I asked about it at a couple of parts stores and got blank stares but I didn't have a card to WHIP OUT!

You have to be able to whip something out of your pants to be effective...

I do not have mine... I accidentally acquired the 7 cans of R12 I have...and you know I know and respect the rules... also have my can of R22, big nitrogen cylinder, etc...

How about this?
http://www.epa.gov/ozone/title6/608/technicians/608certs.html