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View Full Version : Replace A/C system, 134a upgrade information



callen
05-20-2004, 04:32 PM
Well my compressor locked up and I'm going to change out all components...yea I know nuts but.....anyway.

How should I distribute the oil....should I put it all in compressor....little in Evap, cond. and rec dryer?

Thanks
Callen 91 535i 5spd soon to be really cool.

bahnstormer
05-20-2004, 05:46 PM
go r134a

Bill R.
05-20-2004, 06:26 PM
evap and cond. just fine ...







Well my compressor locked up and I'm going to change out all components...yea I know nuts but.....anyway.

How should I distribute the oil....should I put it all in compressor....little in Evap, cond. and rec dryer?

Thanks
Callen 91 535i 5spd soon to be really cool.

winfred
05-20-2004, 07:59 PM
it would be a cheeper to buy a flush gun from napa, i just got one a couple weeks ago, gun/tank and a gallon of flush cost me $125, the flush is about $50 a gallon, i think they sell smaller containers, about a pint does a evap or condensor fine. you do need a compressor to charge the tank and then blow the lines free after flushing


Well my compressor locked up and I'm going to change out all components...yea I know nuts but.....anyway.

How should I distribute the oil....should I put it all in compressor....little in Evap, cond. and rec dryer?

Thanks
Callen 91 535i 5spd soon to be really cool.

callen
05-21-2004, 08:55 AM
thanks

callen
05-21-2004, 09:00 AM
I've had a slow leak since I've had the car...also its a 91 and didn't get much air out of vents and it smells bad so looked and after 240K miles the evap was really dirty...plus the compressor did disintegrate.....finally this compressor is not cheap so don't want to take chances...finally in Houston need coooooold air...kinda like LA....also converting to R134...

Thanks though for info..... didn't know about flush gun..

Bill R.
05-21-2004, 09:24 AM
list of changes on the e34 after 8/92 when they changed to r134a, the newer condensor for the 93 will be the higher efficiency for 134a already, same with the expansion valve, compressor and clutch, evaporator, etc...when you order your parts I'd order them for a mid 93 535 to make sure that you get the stuff for it plus i'd order the conversion kit that bmw sells with the different pressure switches and wiring harness...http://www.bimmernut.com/%7Ebillr/images/callen1.jpg
















I've had a slow leak since I've had the car...also its a 91 and didn't get much air out of vents and it smells bad so looked and after 240K miles the evap was really dirty...plus the compressor did disintegrate.....finally this compressor is not cheap so don't want to take chances...finally in Houston need coooooold air...kinda like LA....also converting to R134...

Thanks though for info..... didn't know about flush gun..

callen
05-27-2004, 03:58 PM
where can I find the amount of PAG oil to put in system....stopped by dealer to pick up new o-rings and tech told me about 2.5 OZ's and to put it in while pulling a vaccum rather than directly into compressor......can this be right? Know in past I just poured some in rec dryer and compressor as you suggested.

Thanks

Callen 91 535i still steamy.

winfred
05-27-2004, 08:04 PM
i drain the compressor and blow or flush the rest of the system and pour 5-6 ounces of ester into the compressor (i find this amount covers all of the euro cars i work on, volvo/mercedes/bmw) most compressors i get recomend 5-6 oz of oil, before you start the engine turn the compressor over by hand about a dozen times to clear the cylinders of liquid


where can I find the amount of PAG oil to put in system....stopped by dealer to pick up new o-rings and tech told me about 2.5 OZ's and to put it in while pulling a vaccum rather than directly into compressor......can this be right? Know in past I just poured some in rec dryer and compressor as you suggested.

Thanks

Callen 91 535i still steamy.

winfred
05-27-2004, 08:07 PM
ps, i've seen in a few books that pag and r134a combine and do bad things to copper, you might want to think about that, older bmws can have some copper in their systems

callen
05-28-2004, 12:26 PM
thanks for info......

jplacson
05-28-2004, 11:19 PM
Ok, I'm still running the original R12 system... but just in case my compressor dies... what do I have to change to go R134a?

Are all I need the retrofit kit and a new R134a compressor? Everything else stays the same?

winfred
05-29-2004, 12:44 AM
to do a retro on a running system, i drain the compressor of oil, replace the dryer and expansion valve, while the system is apart i blow as much oil from the system with shop air as i can, (now that i have a flush gun i flush the evap and condensor with ac flush solvent, $125 from napa for the gun/tank and a gallon of flush, i use a 1/2 pint at a time it's $50 a gallon) replace the fittings with quality steel fittings with their own valves not those shitty aluiminum ones that use the old valve, the good ones you remove the core from the old fitting before you screw on the 134 fitting on, refill the compressor with about 6 ounces of ester ac oil and vaccum the system down for about a half hour and charge with 3.4 pounds of r134