AC leaked out. Recharge needs oil?

[Kurtatron]

I recently started my old 1991 Toyota Previa for the first time since last november. Of course the old steed started right up (w/ fuel stabilizer). Unfortunately, to my dismay, the A/C wasn't working. I charged the system up, and it began cooling right away. I used a canister that has dye in it to help find the leak. The leak is a small and slow one, so I'll need to drive the van for a couple of days to get the leak to show up. Until then, does anyone know if I will need to replaced lost lubrication oil due to the leak? It's an older R12 system converted over to R134a, but it had PAG oil mixed in to lubricate the older compressor. Should I add some PAG oil now after the recharge? Keep in mind the Toyota TSB calls for PAG oil when the system is converted over to R134a. But I have heard somewhere that the PAG oil does not leak out when the refrigerant leaks out. Can anyone verify this? I do not want to run the AC without lubricant oil for the duration of the leak detection driving period.
Thank you everyone.

 

[berniedd]

Happened to me too. After 4 months of nonuse, the a/c in my 1998 Honda CRV did not cool. A/C tech said no leaks found. He then asked if I'd parked it for a long time. I said 4 months, andhis reply was the o-rings at the tube couplings dried out and leaked. He changed the o-rings, recharged the freon, and all was good. No a/c oil was added. He advised to use the a/c every few weeks at the most to keep the seals in good condition.

 

[Chris142]

Ester oil. Not PAG for a retrofit.

 

[Kurtatron]

Chris, the Toyota Service bulletin said to use PAG ND-8 oil.

 

[Donald]

I don't suppose you would consider getting the leaks fixed? If you never plan to take it to an A/C shop then go ahead and use R134a with STOPLEAK.

 

[Chris142]

Chris, the Toyota Service bulletin said to use PAG ND-8 oil.

That is only after doing a complete flush. Most places don't flush. Pag and mineral oil are not compatable and become a gooey mess. Ester works with both. I know Toyota says not to flush. IMO they are wrong.

 

[Kurtatron]

That's why I put in r134a with dye. I am trying to find the leak. But it takes time for the dye to appear on very small leaks.

 

[JHZR2]

I don't suppose you would consider getting the leaks fixed? If you never plan to take it to an A/C shop then go ahead and use R134a with STOPLEAK.

This is illegal. CAA effectively mandates that leaks must be found and repaired prior to refill. Proper approach is to fill with bone dry inert gas, with a bit of r22, r134, etc., sniff the leaks, and figure out where they are. That gas with the trace refrigerant can be be released to the atmosphere. Once fixed, then fill with R12 or R134. If the system came with R-12, and doesnt have all systems ready fro R134 (including cutout switch, condenser design, etc), performance may be poor. I dont recall that our Previa AC was all that powerful ever...

 

[mk378]

Oil typically doesn't come out through small leaks at all unless the system is running. Which is how detecting leaks with dye works, it needs to be running to mobilize the oil / dye mixture to the leak.

 

[willbur]

Happened to me too. After 4 months of nonuse, the a/c in my 1998 Honda CRV did not cool. A/C tech said no leaks found. He then asked if I'd parked it for a long time. I said 4 months, andhis reply was the o-rings at the tube couplings dried out and leaked. He changed the o-rings, recharged the freon, and all was good. No a/c oil was added. He advised to use the a/c every few weeks at the most to keep the seals in good condition.

Yeah me too. I ran my AC in my Honda 20 min every week summer and winter to prevent seals and fitting O rings from drying out. No dice. Still leaked out. No leaks were found. Recharged and air is now 31.8F on a 93 humid day

 

[nthach]

The OEMs prefer PAG oil, retrofit preferred POE oil - it’s more miscible with trace mineral oil and it doesn’t break down in the presence of CFCs that might remain in the system.

If you care about your car, don’t use those all-in-one refrigerants like AC Pro. The sealers in those will damage recovery machines and might cause unnecessary harm to your system. Typically, unless there is a component replacement or a major leak, you shouldn’t need to add oil. If you need to add oil, I think it’s 1/2oz for leaks and a ounce in each component except for the compressor that holds the majority of the oil charge. Toyota systems typically hold 100-130 cc/ml of oil(3.4-4.4oz). Charge to 80% of the rated R-12 charge in R-134a.

 

[zzyzzx]

The problem with assuming that no oil leaked out is that there could be some leaked out oil well hidden behind the compressor clutch.

 

[Kurtatron]

Thank you for the help. I will use Ester oil next time after the leak is resolved. The high pressure manifold gauge is still connected to the high port (for 2 days now), and only 10PSI has been lost thus far. I am beginning to think tackling this leak may not be worth it. The dye has not shown up anywhere either. Hopefully it's not the evaporator. Actually, one of the absolute nicest things about Previa's, the dash does not need to be removed to access the evaporator. The evaporator can be accessed from the hood. I wish more modern cars were like that.

 

[mk378]

Don't mix oil types. If it has PAG now keep it PAG. Too much oil will reduce performance.

Nearly all 1990s Japanese cars were designed for the dealer to install the A/C system after importing the car without A/C. This technically gave the car a USA value-added content which reduced import duties. So none of the A/C parts are buried needing major disassembly to reach.

 

[Saabist]

This is illegal. CAA effectively mandates that leaks must be found and repaired prior to refill. Proper approach is to fill with bone dry inert gas, with a bit of r22, r134, etc., sniff the leaks, and figure out where they are.

Effectively unenforceable against individuals. People who work on their own cars "top up" AC systems with slow leaks all the time and there is no way for Big Brother to know about it. Certainly a shop would need to keep its nose clean though. The reason to avoid sealers is the havoc they can cause both in your AC system and recovery equipment. I cringe whenever I see someone buying a can with that stuff in it.