andrewg

My "89 s2 needs an ac charge. At $90/lb (can) for the freon, I'm wondering how much for an R134 conversion. Also how many pounds of freon to fill the system. The ac works , but the low pressure cut off shuts it down after approx 20 sec of the compressor running. Anybody with experience with costs for an R134 conversion?

Thanks
andrew
89 s2

Greg Hammond

I converted my 87 951 for about $35 with a do-it-yourself R134a conversion from Wal-mart.

To do it right, you really need to evacuate the R12 (legally) and pump out as much of the R12 compatible mineral oil as you can.

R134a capacity is somewhere around 26 oz. I think the stated R12 capacity is 34 oz. Don't forget you also need to add 8 oz of R134a compatible compressor oil.

Greg

Tabor

Shouldn't the drier be changed at the same time?

jonathan944

I'm happy with my R134a conversion. I also have read the drier should be replaced. The hardest time I had was getting a valve to fit on the ac compressor (low side). I used a 90 degree conversion valve (approx. $5-$10)...(NAPA auto parts)
Sure do enjoy cold ac and cheap freon!!!

-didn't end up changing my drier...

Dan in Pasadena

Jonathan944 - How long has it been since the change? (how long has your drier/compressor lasted so far?)
Greg Hammond - I would love to do my own re-charge...Wal-Mart kit, etc, but can you describe how easy/difficult it is? If you illegally vent the R12 like they used to do routinely..does that evacuate the R12 oil or how did you "pump" it out?
The refridgerant does NOT go into the fitting right on the top left (driver's) side, right? I hear it's lower near the compressor. What else can you tell me?
ANY help appreciated. Thanks in advance, -Dan

Tabor

The compressor should hold up fine. You should take it off to clear it of the R12 oil. If you do illegally vent the R12, you will still need to vaccum down you system for ~4 hours before filling it with the R134a.

Dan in Pasadena

Tabor, Thanks for the quick response. I hate to be a dunce, but...
Take off the compressor? HOw would I "clear" it of the R12? How difficult is it to do?

When you say vacuum my system for about four hours, how do I do that? What do I need to pull a vacuum on the system and do I do this after "clearing" the compressor, re-assembly, then vac the whole system?

Tabor

[quote]Originally posted by Dan in Pasadena:
<STRONG>Tabor, Thanks for the quick response. I hate to be a dunce, but...
Take off the compressor? HOw would I "clear" it of the R12? How difficult is it to do?</STRONG>[QUOTE]

It is the old oil that you want out of the pump. My understanding is that you take the pump out and turn it upside down.

You need to take your car to an AC shop. They will have the equipment to vaccum your system out. This is the correct way to recharge any AC system that has been exposed to the atmosphere.

jonathan944

Dan,
The preferred method of evacuation would definitely be to take it to an AC shop, and have the system vacuumed. My system was emptied of R12 (by way of leak) already. I have read that the new R134a oil they are using are completely compatible with original R12 oils. The older R134a oils were known to turn into a gel when mixed with R12 oil, causing compressor failure.
I actually used a kit I bought from KMart, and also bought the cheesy gauge they sell. My conversion went virtually hitch-free aside from needing to get the special 90 degree service port.
I retrofitted R134a in May...

IPC

There is another choice for a freon. It's called freeze 12 and it is a direct replacement for R-12. No changing dryer,compressor,lines or even the oil. Just evacuate and vacuum the system down then charge it. The freeze 12 cools better than the 134A and cost the same or less.

Greg Hammond

There are a number of R134a/R12 alternatives, but quite a few of them use highly flammable refrigerants (like Propane, Butane, and Methane). Any gas that liquifies at a reasonably low pressure is a candidate for becoming a commercial refrigerant... and for causing an under-hood fire in a system that has a small leak.

Another problem with alternative refrigerants is that no respectable A/C shop will purge/vacuum your system if you need a REAL repair. The R134a/R12 alternatives cannot be recycled/reclaimed, and use completely-different high-side and low-side connectors too.

Greg

IPC

Freeze12 is non flammable.