dr bob

It's $10 at Big Lots, $11 at Wal-Mart. But, Cali has added a $10 'deposit' per can, and the available cans have a built-in shutoff valve so you don't just vent the rest of the can when you top off a system.

I'll probably grab a couple cases of R-134a when I next visit the east coast in a week, and ship them back here. Ditto on some real paint and solvents, big jugs of 15W-50 M-1 from Wal-Mart, and likely more as I think about it. My cherry garage doors need refinishing this year, and the real good marine varnish for them isn't available here anymore. I have to smuggle it in.

dprantl

Dew point is now above 60 deg F day and night. I do find that when it is this high, if the recirc flap is not working and is allowing outside air in, the A/C will never be able to cool the car down properly.

Dan
'91 928GT S/C 475hp/460lb.ft

dr bob

It will be 75º in the heat of the day today, with ~30% RH right now. 62º right now and sunny. Hottest times here are when there's ahigh-pressure area stalled just north and east of us. It causes on-shore winds across the deserts to warm things up, but it's a dry heat. Like just a few percent RH. Temp at a dry 100º is more comfortable than east-coast 80º and humid. There's a reason why 78 bazillion of my closest friends are here, and it isn't the taxes, housing costs or the job market.


I might need to briefly turn on the AC in the car a bit today, just to quickly cool it down after a sun-soak in the Home Depot parking lot. By July that will change, but for now it's not really needed.

rcrone928

dr bob. thanks for the science lesson. Why not just drive accros the border from th peoples repubic of cal into arizona for all that life destroying paint and oil? I used to live in cali and loved it but, the system there is to self destructive to make living there worth it any more. anyway where could i get the afore mentioned high pressure swith?

dr bob

The switch is standard on factory R-134a cars, so a switch from a late-'93 on car should do the trick. The switch screws on to a standard 1/4" tapered-seat Schraeder fitting (same kind that the R-12 charge hoses connect to), so a little shopping might find one that has the same electrical connections as the one you have. If you get the later Porsche part, you'll need to make a little adapter that puts the two contacts in series, with pigtails that the factory wiring can plug in to.

On driving to AZ-- it's a thought, but with fuel costs and time required, I'd need to combine it with another visit to make it worthwhile. Plus some of the stuff isn't available in Arizona either. I have the pleasure of travelling to different parts of the country on business, so when I know I need need something I just buy it there and UPS it to the house. I also found the garage door varnish I wanted on-line last time. Seller had no problem selling it to me, then packing and shipping it. Cali currently has rules against Cali sellers offering it here, but there aren't rules about me importing it or using it. At least not yet. Another example - I had some great Sikkens wood finish for my balcony railings shipped from Germany pretty painlessly; can't find it anywhere in the US, although there are watered-down (literally...) versions I can find here. The watered-down versions cost the same but have 1/3 of the VOC's; and last a third as long. So total VOC's works out the same in the end.

WallyP

" The watered-down versions cost the same but have 1/3 of the VOC's; and last a third as long. So total VOC's works out the same in the end."

That is politically incorrect thinking, and is simply unacceptable.

Correct, but unacceptable...

kingsmen11

I am rebuilding the AC system on my 87 and converting to R134. The compressor is freshly rebuilt and I am flushing all the lines with a special AC system cleaner. Do I still need to use Ester or Can I just use PAG. Also how much oil do I need to put in the system, it only has the front AC.

Thanks

WallyP

New installations use PAG. Converted systems use POE.

If the system has been run with mineral oil (that is, with R-12), I would never use PAG. It is not compatible with mineral oil, and I seriously doubt that you could ever get all of the mineral oil out. PAG might work - but why? POE works fine and is compatible with mineral oil. Why risk having jelly in the system for no gain?

Porsche specs (Page 87-90 in the Factory Workshop Manual) say that an '87 with a 6E71 compressor and no rear air should use 260-300 cc of POE and approximately 30 ounces of R-134a (80% of the R-12 spec).

The oil should be distributed thru the system:
Compressor - 40%
Evaporator - 35%
Condenser - 15%
Receiver/Dryer and Lines - 10%

Good luck with the distribution...

jwillman

OOPs. When I did mine all the oil was put into the compressor before system assembly. Did I screw up? Whats the impact of the method I followed?

blown 87

Not a thing, you are fine.

WallyP

If it worked, you are OK. The distribution is so that you realize that if you replace the compressor and do not totally flush every component, part of the system oil will be in the other system components. In that case, you do not want to add the full specified amount of oil to the compressor. If you do, you will have too much oil in the system, which will degrade performance slightly.

IrishLegend

Tag

Red Flash

So, my air conditioning system (along with a lot of other systems) on my 91 GT is in parts. There seems to have been a rather poor conversion done, and I really prefer R12 anyway for an older system.

That having been said a question for the experts. Is the following compatibility table correct?

Mineral Oil : R12

Ester Oil : R12 and R134a

PAG: R134a

This means, if I am interested in filling a completely flushed system up with R12, I could use Ester Oil and make a later conversion much easier? Correct? Is anybody using Ester Oil and R12 in there 928 here?

Rob Edwards

Yes. I have used ester oil in a couple of 90-91 cars with R12, and in my '93 GTS with r134a. No issues.

The Forgotten On

I would stick with mineral oil unless the POE oil explicitly states it is compatible with R12.