I heard a rumor that spending too much time around Freeze 12 will cause you to loose your spelling ability. Don't know if it's true, though.

http://ackits.com/index.cfm?fuseaction=black%20death

Your method is not a recommended method in the automotive AC industry. It is recommended that you flush the system and add the appropriate oil for the freon used.

When the system has been running and you turn it off. Oil was carried throughout the system in a vapor/liquid state. So when the system is shut down you have the oil distributed throughout the system. When replacing various parts of the AC system you add oil to the particular component. The amount is based on which component it is. This ensures that you have a whole charge of oil in your sealed system. Flushing the compressor involves draining the old oil. Filling the compressor with oil, draining that oil and doing this a couple of times to remove the old oil. The other compnents can be flushed with a flush gun and compressed air. You don't use compressed air on the compressor.

The industry has also found out that the mineral oil saturates and seals the hoses. So changing to barrier hoses is not necessary for a R134 conversion.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Heck, I guess I need to get this can of R134A outta my pants.........

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I read too much on intarweb forums and of intarweb based products. I don't even notice when something is spelled wrong anymore. My own spelling ability (which was never grand) is also going down hill.

Hrm... why was that down your pants anyway?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

He was just happy to see you.

I am not a lawyer, I can not take responsibility for your actions, however:

It is illegal to replace R12 with a non-approved refrigerant. It IS NOT ILLEGAL to replace R134a with a non-approved refrigerant. You can replace R134a with Enviro-Safe or your own mix of R290 (propane) and R600a (isobutane), as far as I can tell.

I glean this information from a few sources:
1. this page
2. places that sell Enviro-Safe
3. My own reading of the clean air act. The pertainant sections are 602a and 612c.

Note: 15 states have banned flamable refirgerants of their own accord.

Re Enviro-Safe:

Critical temperature 205F? Is that a misprint? And to install, pull a vacuum of no more than 10 inches. Huh?

Something is funny here.

I am no AC junkie, but what is wrong with a critical temperature of 205F?

Boiling point (F):
R12/R134a/Enviro-Safe
-21/-15/-30.4

Critical temperature (F):
R12/R134a/Enviro-Safe
233.6/214/205

As for the vacuum, it won't form acids with any water left in the system... why they don't recomend anything more than 10", I can't say.

I have it. They say if you charge from a deep vacuum you will overcharge your system and decrease performance. This is because they tell you to charge until you manifold gauge set says you have the right pressure of the low side of you compressor (the right pressure for R12).

I bet if you worked up your own amount of charge carefully by monitoring vent temps, you could charge with less from a deep vacuum.

That sounds likely. I'd think that you would get decreased performance with any air in the system (but it still might be better than 134a).

As for the critical temperature, one of the biggest complaint of 134a is that its critical temperature is lower than that of R12. This appears to be lower still, but perhaps it runs so much cooler at the condensor that it doesn't matter. The main problem might be that the condensor could start out at 205F from heat off of the radiator. If the condensor is at the critical temperature, no cooling can happen.

Have you used this stuff?

No, but I have been reading a whole lot about refrigerants recently and I plan to.

EDIT- My manifold gauge set and vacuum pump are in the mail. I just need to get the head back on the Volvo before I can devote time the the AC on the Mercedes.

Where did you get the pump? I assume that this is an evacuator only, and not a reclaimer.

If so, do you plan to just take the car in to have the 134a sucked out before you begin? I think that's what I'd do.

Frankly, you really got me thinking about getting rid of that nonsense.

Yep, $16 from JCWhitney. You have to own a good air compressor to use it, though. Otherwise I think the cheapest you are going to find is this for $136.

Indeed. Not only is it illegal to vent R134a, it is a greenhouse gas that is much worse than C02.

Here's one for $99 bucks. I just purchased a flush gun from these folks, and am very happy in my dealings with them. Gun isn't here yet, but have just been nice folks to deal with.

http://cgi.ebay.com/ebaymotors/FJC-Automotive-2-5-CFM-Vacuum-Pump-R12-R134a_W0QQcmdZViewItemQQcategoryZ43989QQitemZ4645271505QQtcZphoto

(I wish I knew how to rename my links)

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John