AC questions

[tom h]

Due to not operating or servicing the GN's stock AC system for several years, the R12 refrigerant pressure (with engine off) has fallen to just 5-10 lbs (equal on high & low sides). I'm pretty sure this is due to gradual loss, and not a detectable leak.

1) If I decide to just add more R12, Will any of the oil necessarily have escaped? or could one just add pure R12, assuming all the oil was left behind?

2) If oil is likely to have escaped along with the R12 , how could you even begin to estimate to how much new oil to add

3) I've also read some articles, that Ester oil (but not PAG oil) is supposedly backward compatible with R12 & old mineral oil. Is it OK to just use Ester oil , if needed? It's a lot easier to find in auto parts stores.

TIA.

[Chris Cornett]

The R12 will cost you about $70 a pound Times abou 3 pounds(I think) so that sucks. As for the oil I have always used mineral oil in systems that were not evacuated.

[1ARUNEM]

Just had an R12 system converted after sitting for a long period. Cost about $150 total to go to R134.. 134 is much less costly if any is ever needed in the future also.

[tom h]

Originally posted by Chris Cornett
The R12 will cost you about $70 a pound Times abou 3 pounds(I think) so that sucks. As for the oil I have always used mineral oil in systems that were not evacuated.

Actually I think I can get some for about $30 per lb, so in the short term it's easier & cheaper for me (keep same drier/accumulator, no flushing, etc).

Still, the open question remains, Would oil have escaped along with the R12? And if so, how much to add? Surely it won't require a full charge of oil ??

[salvageV6]

I'd skip the oil.

When I bought my GN 3 years ago the A/C was dead.

Don't remember if it had much pressure or not.

I just put 2 cans of my precious R12 in there and it has worked fine for 2 years now.

I may have used a can of stop leak for R12 but I can't remember some of those have 1-2 oz. of oil too.

Search the lines for obvious wet spots and leaks and retighten any loose fittings.

I doubt you lost much if any oil if it was not visible somewhere.

[Chris Cornett]

$30 a pound thats cool(no pun intended). Just keep an ear to see if the compressor makes any noise when engaged. If not the I would say you are OK.

[chevyII]

The oil is carrried by the r12 when in the system. If the sytem is empty add 6-8 oz. This will be picked up and moved in the system as needed. The best thing is to vaccum the system as the system has air/moisture in it and will cool much better. Now as far as refrigerant goes go with R134a you dont have to change a thing.The only parts needed are the valve adapters and freon. Nothing makes a difference in cooling like pulling a vaccum for 45 minutes.