Engine Size: 305
Refrigerant Type: 134a
Country of Origin: United States
I did a retrofit back in May. I could not find anymore r-12 at the time-eventually found some more afterwards..but I followed steps outlined on my other forum and some of the suggestions off AllData. I vented, vacummed down to 30 in/mg for 45 mins, killed a 6 pack and it still held vacuum-1 hour afterwards. I followed the % call for 134a compared to r-12 regarding pag oil and refrigerant. started car jumpered the compressor, added the amts and had cool air.
Thought that was the end. was driving and a/c cut off while accelerating, used manifolds to check pressures it was a little low for the ambient temp outside. added another can. didnt have a problem till july. it got low again compressor was cycling. added more 134 and looked around and could not see any visual clues as to why i was loosing.
what steps should I take to resolve this? just o-rings? someone said pag will eat r-12 o-rings...idk
and another question is what can i do to improve the performance of the retofit. Idle speed r-12 was superior. seems the same either way on highway. I have a clutch fan.
new to this forum and if there are any post i should take a look at lemme know
This all started because the R-12 had leaked out in the first place, so it has had a leak before you started. Need to find it. Most GM compressors are doomed to eventually leak at the shaft seal. O-rings don't absolutely need to be replaced when you convert, but they will get hard and fail anyway after so many years.
I don't see anything about replacing the drier, it's definitely spent by now.
the leak i had with r-12 was at the low sericer port so i figured it would be fixed with new. planning on replacing orings, orifice, and the accumulator. is there anymore info on this seal you referenced earlier? have not seen any tsb's for this
So if I read this right:
1) You vented the R12 to atmosphere.
2) Evacuated the system
3) Added 134a at some percentage of OEM R12 charge
Is that right? Did you in fact add any 134a compatible lubricant?
What you have right now is a mess. Wrong oil / too much oil (depending on what you put in it) An R12 dryer still in a system full of 134a. Needs to go back to square one & do a proper retrofit.
But first, the leak. Since you have a mess already, I would add a dye charge & run it for a few days. The UV dye will show you where the leaks are. Probably a shaft seal on the compressor, but there may be others as well.
Find the leaks
FIX the leaks
Flush the system back to bare metal
Install a new dryer for 134a
Add the OEM quantity of lubricant to the system
Replace the fan clutch with a new GM part.
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
I never said where i vented..
i went 90% of refrigerant capacity and added the proper amt of pag oil. though I did not know GM had a pag for retrofits...
the dryer's are just dryers from what i see available...the TSB on the retrofit said it wasnt needed to change based on the different refrigerants.
I plan on changing mine since its been lossing charge & its so cheap and new o-rings as well...
GM didnt make the fan clutch's they just put their name behind one. I do have a new hayden HD thermal fan clutch
I'm going to get the dye and see. if it was at the compressor wouldnt there be oil weeping out to?
You did say you vented in the first paragraph of your original post. They say you can send Al Gore some money as penance, and he will fix it for you; I am not to sure about that. Anyway...
The OE TSB's regarding retrofits are old and now (today) considered to be flawed, given the number of failed results; but they will not be rewritten or corrected for such older vehicles.
You have a leak, add some dye or use a leak detector to pinpoint the leak problem. Recover the refrigerant, flush out the PAG/Mineral oil mixture (it is a chemical concoction that tends to turn into "goo", and will not produce good lubrication). Make sure everything is dry (no solvents remaining), fix the leak, fill with proper amount of PAG or POE oil, vacuum, and recharge.
The charge should be near 100% of the factory prescribed amount to produce proper lubrication circulation. Lesser charge amounts are usually recommended to overcome poor condenser and clutch fan performance. It is recommended that these items be upgraded (parallel flow condenser and OE fan clutch) rather than compromising oil circulation by using less refrigerant to compensate.
OE's have their clutch fans made to their specifications; the same manufacturer will often take short cuts and cost cutting measures to produce a similar (they say "same") product for the aftermarket. The OE clutch fans are superior regardless of the aftermarket marketing BS, and this is why they are recommended.
Hope this helps.
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