dirkdiggle

iTrader: (1)

Hi,

My Air conditioning compressor on my 92 SC400 (R12 freon) recently crapped out on me. I went on ebay and bought a used compressor off of a 1995 SC400 (R134 freon) to swap with my broken one. Questions are as follow:

Can I just put my new compressor in and fill my existing system with the R134 Freon????

If not, can I put the new compressor in and fill with R12 freon, so pretty much R12 freon used in a R134 compressor???

What is all involved with converting the A/C system on this car and how much $$$ am I likely to spend minus the price of a compressor cause I already have it??? a list of parts needed with descriptions would be great!

I have already seached on this site but I have just found a list of part #'s without any explaination of what they are exactly . I would really like to use the R134 fron cause its easy to obtain so what do you guys suggest I do?????

Thanks,

dirkdiggle

iTrader: (1)

anyone????

mitsuguy

iTrader: (2)

IMO, not a good idea...

you will at least have to replace the receiver / drier and expansion valve.... while you are at it, you should replace the condenser with one designed for R134a as well...

dirkdiggle

iTrader: (1)

does this sound accurate?? I have to replace receiver and drier??

mitsuguy

iTrader: (2)

receiver/drier - its one piece... it should be changed anytime the compressor is changed... it collects oil from the system, and the drier takes moisture out of the system - any time the system is opened for repair work, its not a bad idea to replace, it should always be replaced if the compressor is replaced...

l1tech

Mind if I ask what happened to your old compressor?

dirkdiggle

iTrader: (1)

when I push the A/C button the compressor seems like it trys to engage by making a horrible noise for 4 seconds then stops and a/c button light flashes. I assume this means it is toast??? I bought this used compressor off of ebay from a 1995 SC400. do I really have to replace the reciever and dryer or can I get away without it??
remember I just plan on putting a r135 compressor in a r12 system.

mitsuguy

iTrader: (2)

why don't you listen to someone who works on A/C systems every single day in one of the hottest cities in North America?

you probably killed the compressor by trying to use it...

does the system have refrigerant in it? did you replace the receiver/drier that has R12 style mineral oil still in it? did you add PAG oil required for the R134a compressor? did you evacuate the system of all moisture and fill with refrigerant?

if you didn't do those things, and the compressor actually turned on, then you killed the compressor because you didn't listen to me...

you need to save up about $1200 and take it to a licensed a/c tech and get the job done right...

to do it right:
compressor, receiver/drier, flush the system, add proper oil, evacuate, recharge, and if you are dead set on switching to r134a, then you should consider replacing the condenser with one designed for r134a that has a larger surface area and smaller tube/fin designed for the smaller molecules of r134a... while you're at it, new o-rings, also designed for r134a are fairly important as well...

dirkdiggle

iTrader: (1)

So...... I should sell the 1995 r134 compressor i just bought and wait till a R12 compressor comes around?? This would be the cheapest/logical route?? What if I used r12 freon in a r134 compressor??

mitsuguy

iTrader: (2)

IMO, yes... I mean, PM Aliga - he probably has one laying around if you are looking for a used one... my personal opinion, a cheap rebuilt ebay compressor might be the better cheapie option, $240...

dirkdiggle

iTrader: (1)

I found a receiver/drier at autozone for $120. How hard are these parts to install??

mitsuguy

iTrader: (2)

with a/c, it's not the ability to install the parts that is the tough part, it's following all the little rules you learn through ASE and through other a/c certification schools and seminars, not to mention hands on experience...

probably take ya 20-30 minutes to install... maybe...

don't forget the expansion valve...

edit: I just checked... we sell receiver/drier for $35 retail and thats for Denso OEM...The expansion valve is around $100... it is a little harder to replace...

GRAND_LS 4

iTrader: (2)

I took my '93 SC to a nearby trusted shop and had it converted for less then $80 bucks. A/C works great, and it has been for years. Not sure why you need to replace the entire A/C system.

Also not sure why the A/C tech/shop owner here is getting upset at you for not doing what he asked? Unless you barrowed his car?

Just have a trusted shop vacuum the old stuff, and put in the new stuff, and you should be all set. IF for any reason it doesnt work, by any remote chance, or out less then $100.

mitsuguy

iTrader: (2)

not upset, just if he doesn't want to believe an experienced A/C tech, that's all good...

as far as conversion... if it doesn't work, meaning as if it's not done properly, oil is not drained out of the compressor, and proper oil added, the thing will work, but not reliably, and the compressor will die...

for a proper conversion (I can scan the ASE and tech sheets if you like), you need to recover any existing freon in the system, then remove the compressor and drain it of oil... The receiver/drier should be replaced as well, as it contains compressor oil as well (r12 systems use mineral oil, mineral oil is too heavy for R134 systems to circulate)... The whole system should be flushed then... All O-rings and seals should be replaced... then the system should be reassembled, evacuated and recharged, whilst adding proper amount of R134 compressor oil (typically PAG)...

that will get you a decently functioning conversion...

for a proper conversion, you would want to replace the condenser as well with one designed for R134...

as far as the expansion valve replacement - that has less to do with the conversion, and more to do with it being a very small valve that is subject to contamination - any time a compressor takes a dump in a system, there is always a good chance that valve will become plugged - if it does, it's bye bye compressor in a quick way...

sometimes the best way to save money is to spend it correctly the first time...

your shop, with their $80 conversion... wow... I would hate to see what shortcuts they made... probably didn't drain the old compressor, probably short filled it with R134... probably didn't flush the system... I'm sure it works great now... when I fix a system, it's going to have OE longevity, not a questionable lifespan...

mitsuguy

iTrader: (2)

Alright, I finally stopped being lazy - Toyotas recommendations as far as retrofitting:

Oil removal: not necessary, but recommended.
Receiver/Drier: MUST be replaced with a drier that contains XH-7 or XH-9 desiccants (OE is XH-5 and not compatible with HCF-134a)
Compressor seal: must be replaced if more than one year durability is required
Hoses: Must be replaced if more than 2 years duability is required
Lubricant: Full charge of PAG lubricant
Refrigerant: R134a

For a Toyota dealer to do this retrofit, R12 must no longer be available.