More ac advice! - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 06-14-2009, 10:53 AM

Quote:

Originally Posted by Matt L

If you vacuum for 24 hours, you should use an electric solenoid valve in the line to the pump. That way, if the power fails overnight, the valve will close and you won't draw pump oil into the system. You don't want vacuum pump oil in the system.

I did not know that. And since I do believe in the long vacuum I will find one of those electric solenoids....'any excuse' to add to my AC tools.... LOL

compress ignite · #17 06-15-2009, 12:12 AM

Matt L,

Learn something New every !

Pelon,

Somedays you just get Lucky !

badtruckrisin,

Click on the Buy Parts tab @ top of Page and talk to Phil.

dablk1 · #18 09-04-2009, 07:01 AM

I'm not sure if my car uses 112 or 34. How can I figure this out? I asked the PO and he didn't sound to certain.

#19 09-04-2009, 07:22 AM

Quote:

Originally Posted by dablk1

I'm not sure if my car uses 112 or 34. How can I figure this out? I asked the PO and he didn't sound to certain.

I hate that I have to apologize for all of us here at Mercedesshop, but our mind reading skills are VERY weak! We all would want very much to answer your question except for one minor detail. We don't have a clue what "your car" is. Is it safe to assume that it was built by Mercedes Benz?

What would be helpful to you for getting your questions answered, would be for you to go to the top of this forum and read the post entitled "Troubleshooting, getting the most from your post."

#20 09-04-2009, 07:28 AM

Quote:

Originally Posted by badtrukrisin

I am planning on a complete rehab of my ac system. My questions are, I would like to go to R134 and I know the system is designed for R12. What needs to be changed in order to make a R134 system efficient? Different compressor, condensor, evaporator, expansion valve, pressure switches and driers? I don't know if a system can be changed to meet efficiency so that is why I am asking. Not trying to create a P@#%$% match so just good info is sought. Thanks

Bud

I'm sorry, but I must have taken much different math classes than most other people. R12 now costs about $5 to $10 more per pound than R134a. The changes you propose to make in order to have the most efficient converted R134a system would be at least in the hundreds of dollars. I just am not good enough with math to understand how spending these hundreds of dollars is better than spending maybe as much as $40 more for refrigerant. This is not to mention that by staying with the refrigerant for which the system was designed you will have better a/c performance AND much longer a/c life.

Please help me understand where my math is going awry.

Matt L · #21 09-04-2009, 10:17 AM

The price difference has got to be more than $10/lb, but that's only because 134a is dirt-cheap this summer. I got a cylinder for $90, which comes to $3/lb.

But of course you are correct in spirit. Even with that "expensive" R12 in there, the refrigerant is one of the cheapest parts of the whole system.

vstech · #22 09-04-2009, 10:35 AM

R 12 is brand new cost 512/cylinder... that's what 18.00/lb... it can be had on ebay, and craigslist for as little as 100.00... I've even gotten a bottle of 12 for free... well I did service the guy's home a/c... good luck!

zeke · #23 09-04-2009, 12:06 PM

I had trouble getting a cylinder of R12 shipped from ebay.

Shippers consider it haz-mat, and charge an outrageous fee for transport.

I refitted the wagon with R12 using old-school castrol mineral oil. A year later I sprang a leak in the high pressure line. Went looking for R12 again, and decided it was too hard. About a month ago I put PAG oil in and used a blend (flamesuit is already on Greg) because I got it cheap locally. I also cleaned the evaporator fins with some coil cleaner from a local hardware store.

Drove to Oklahoma City from San Antonio and back last weekend in triple digit heat with the wife and kids. No complaints. Honestly, I can't really tell the difference b/w R12 and the blend. Maybe at idle in traffic above 95* it is a bit more tepid, but mostly, I feel no difference.

bob_98sr5 · #24 09-04-2009, 12:26 PM

i own the same vehicle as you do, but it has been converted to run R134 . i also have two other cars. its been 100F on and off for about 3 weeks here in CA now. on the worst days, i refuse to drive my car and take my trusty 98 4runner SOLELY b/c the AC works better and runs colder. does that tell you something?

stick with your R12, have it vac/flushed and properly filled. if not, lets swap systems!

#25 09-04-2009, 12:44 PM

I agree, I once converted my 300D to 134a and didn't like the performance. I converted it back to R-12.

leathermang · #26 09-04-2009, 02:12 PM

Quote:

Originally Posted by zeke

I had trouble getting a cylinder of R12 shipped from ebay. Shippers consider it haz-mat, and charge an outrageous fee for transport. I refitted the wagon with R12 using old-school castrol mineral oil. A year later I sprang a leak in the high pressure line. Went looking for R12 again, and decided it was too hard.

About a month ago I put PAG oil in and used a blend (flamesuit is already on Greg) because I got it cheap locally.

I also cleaned the evaporator fins with some coil cleaner from a local hardware store. Drove to Oklahoma City from San Antonio and back last weekend in triple digit heat with the wife and kids. No complaints. Honestly, I can't really tell the difference b/w R12 and the blend. Maybe at idle in traffic above 95* it is a bit more tepid, but mostly, I feel no difference.

After all those emails trying to get you set up right on that job ...and you put in a blend...and in your post here you completely skip over the potential problems in what you did... instead citing the short term and lucky trip you made to Oklahoma as the confirmation that what you did was just as good as using either 134a or R12 ?

I give up on you.

But for the rest of you reading this later... the problem , as repeatedly expressed by those in the know both on this forum and AC industry wide...
is that if he had needed AC work anywhere in that trip in triple digit HEAT WITH his family in the car the chance of finding a shop which would work on it are almost NIL . ZIP, NADA.

If you do not believe me get on the phone and call around your area... tell them you have a blend and need service... and listen to how fast they let you off the phone.

The other potential problem which you do not have with R134a or R12 is oil miscibility ... the ability of the refrigerant to mix with the oil and move it around the system... which is very important if you have a DELCO R4 compressor BECAUSE it HAS NO OIL SUMP... only the oil being circulated by the refrigerant is available to your pump for lubrication.

And it is interesting that Zeke used the generic word ' blend'... so it is a possibility that he used a flammable blend which is not legal in Texas...where he lives...

" I decided it was too hard ".... AC work IS HARD.... so for others with this short term lazy , potentially costly and even hazardous to the health of your family attitude I strongly suggest you take it to pro who knows that doing it right IS HARD... but WORTH THE TROUBLE.

zeke · #27 09-04-2009, 04:01 PM

I told you I had my flame suit on.

The blend I used is not flammable and is completely legal in Texas. It has a pressure temperature curve that is very similar to R12, so the high pressure side is not going to be stressed in the system as much it would with pure r134a.

Of course there are problems with using a blend including (but not limited to) the lack of repair shops that will service my car - a point repeatedly made on many many threads on the forum...but as I mentioned in another post, I have found that very very few shops will do R12 work any more. The last shop here in san antonio i found that did do some R12 work shot some R12 into my system without identifying the source of the leak - so within a few weeks, I had leached R12 out into the atmosphere - not very responsible, and quite costly to me. The most reputable shop here in San Antonio, Carlisle Auto Air does service R12, but only if they have any in stock - last time I called (July, 2009) they had none in stock and were unwilling to do even simple diagnostics on ANY AC system with refrigerants other than r134a.

Let me repeat that - Carlilse Auto Air refused to service my car because it had R12 - not a blend, not an unapproved HC refrigerant.....R12.

"it was too hard" describes the acquisition of a chemical that is toxic to the environment, under strict federal control, and is now considered a hazardous material by all of the major shipping companies.

It does not describe the work involved in getting the AC working properly which included reclaiming the remaining R12 which I now have to dispose of. It is clean and yours is you want to come and get it

In fact, the whole point of my post was that if an AC system is PROPERLY converted, the difference in cooling capacity between R12 and R134a is fairly small.

I am not out to convert anybody either way like others on this forum....I have no vested interest in sales of R12, freeze12, r134, or any other refrigerant.

My temperature drop is 31* at 95*F with FR12. I think I might expect 4* better on R12.

tyl604 · #28 09-04-2009, 04:38 PM

Seems like I saw a news article within the last six months that debunked the R12 freon question. It said that the expansion and reduction of the hole in the ozone layer was a natural occurrence which had always been happening over the life of the earth. It went on to say that the issue with freon was largely political and that the impact of Freon was not important on a global scale

Not sure whether to believe it or not but I also remember that saccharine used to cause cancer - until just recently.

JimmyL · #29 09-04-2009, 10:40 PM

R-134a operates very poorly in W123's when the temps get over 90.
From actual experience, Freeze12 and Envirosafe give me just about the same performance as R12 in a W123.
I sell none of the above and I have no agenda. Freeze12 has been in the white wagon going on 4 years now. I have to add a bit every summer and the loss of a "blend" has made no difference in performance. I understand the theory involved with the various "blend compounds" leaking at different amounts, and while the theory is sound it hasn't made a difference.
If folks want to go with R12 I don't have a problem with that either. Nothing at all wrong with that.
The person with the '85 300SD getting good temps with R134a has the improved condenser in that year W126 which helps the performance in that year SD. Dan has had great luck with that.
Somebody else used the term "over-priced blends". Freeze12 is about $7 bucks a can. Envirosafe was just a tad more. FYI, I've also purchased R12 for about that price too, so it can be had cheaply enough too at times.
Disseminate all the info in this thread and do what you want.......

JordaanDMC-12 · #30 09-05-2009, 12:12 AM

Can you put Enviro-safe r12 into an unmodified r12 system without problems? It's basically an R12 substitute right? but works the same?