Art20c

Hi guys,

Anyone knows how many pounds of r12 in 87 S4 with rear a/c? Cant find this info for my car.
Another question - anyone tried to buy cans of r12 off ebay? They all ask for certificate, is it just the way to keep ebay happy, and it doesn't matter after you bought it or it is serious, that seller will not ship it to you?

Bill Ball

87 w/ rear AC is 1200gm (per WSM section 87, page 90). At 454 gm/lb, that's 2.64 lbs.

I've bought R-12 off eBay. The law requires you to have the certificate unless you are reselling it. I took an online test for $15.
http://www.macsw.org/source/Orders/i...ion=MACS_Store

Rob Edwards

I was looking for something else and came across this TSB that I'd forgotten about.

For posterity:

Art20c

thanks guys

Bill Ball

Yes, Rob's cited tech document confirms the WSM. Tech Spec book agrees. This training document is a bit off.

dprantl

WTF almost every Porsche tech bulletin I see is somehow critically WRONG. That one that Rob posted, the last column for refrigerant oil: Total 280cm3, oil in compressor 280cm3... er, no?!

Dan
'91 928GT S/C

John Veninger

Use a set of gauges and check for the correct pressures when filling.

LT Texan

I've known that the compressor took oil, but do you actually put oil in the condensor, evaporator and drier too?

I've got a new receiver-drier on its way. Hoses on their way too.

SteveG

When I replaced those items, the rebuilder advised: 3 oz of oil in each of, condenser, compressor, and dryer. That was approx 1/3 of the container in each.

Bill Ball

I use the ambient temperature versus pressure charts if "topping off" although I rarely do that. I prefer to evacuate and put in the correct weight.

Regarding oil..If the system has been flushed (not just evacuated), then you add about 350cc to the compressor, unless it is a later 10 PA 20 C type, which uses about 150cc less. It will be distributed as shown below. If you are replacing just a specific part, the volumes are shown.

From WSM, section 87, page 41:

There is no way of checking the oil level in the
air conditioner compressor. The compressor of
a newly installed air conditioner has a total oil
volume of about 350 cc prior to initial operation.
The refrigerant oil will be distributed throughout
the system when operated for a while. The
different parts will then have the following oil
quantities:

Condenser 30cc/1 ounce
Evaporator 60cc/2 ounces
Receiver-drier and lines - approx. 10cc/0.34 ounce
Remainder in compressor - approx. 250 cc/8 ounces

Later in section 87, page 90:
Refrigerant in compressor
Type 6 E 171 = 280 +/- 20cc
Type 10 PA 20 C = 120 +/- 20cc
(The compressors changed over in 89 GT and 90 S4)

In the GTS using R-134a, the oil volumes is 160 +/- 20cc (WSM section 87, page 129)

dr bob

The convention in compressor replacement is to drain the oil out of the old compressor, and replace the same amount into the replacement compressor. Even new compressors, which typically include the full-system charge amount when shipped, include instructions to measure the old charge and restore only that much to the new compressor.

Charging to the gauge readings based on ambients is not the most precise method, unfortunately. The problem with that method is that there's no way to see how much of the condenser is flooded with liquid. Charge by weight if you can, by gauges and sight glass and thermometers as the second choice, and by gauges alone as the least desirable method of the three.

dprantl

Yep, I thought the 10PA20C was much less than the 6E171... if someone was using that tech spec page they would put 280cc in that compressor and hose up the system with way too much oil. Bad Porsche QA

Dan
'91 928GT S/C