Want to be

How much freon does my 1987 928 S4 hold, the car has rear AC as-well.

My R12 gauge does not indicate with red labeling if i am over charging the car.

I can post a picture of the gauge if needed.

Thanks for any HELP.

jpc

Speedtoys

http://lmgtfy.com/?q=porsche+928+R12+freon+amount

Rob Edwards

LMGTFY, LOL......

davek9

now that is funny

dr bob

LMGTFY-- I need a voce command version so I don't have to type my question.

---

OP Phil--

The car at this point has an unknown quantity of refrigerant in it. If it was run so low on pressure that the suction side shows negative, there's a chance that there's air in the system too. Obviously there's leakage someplace or you wouldn't be asking the question about quantity.

-- While there's still some pressure in the system, use an electronic leak detector to identify all the leaks in the system. These tend to be deteriorating connections with o-ring seals where hoses connect, o-ring seals where the fuel cooler and the front and rear expansion valves connect with hardline sections, o-rings where the rear AC lines pass through the floor under the passenger seat, the compressor housing o-rings, the compressor manifold plate o-rings, the compresor shaft seal, the rear AC solenoid valve under the passenger seat and its o-ring connections, the rear evaporator, the frot evaporator, the drier, or the condenser. Or the hoses themselves. The prominent theme is o-rings.

Find the leak, fix it, replace all the other o-rings while you are in there, new drier, evacuate overnight, recharge by weight.

The pressure gauges don't tell you much about quantity of refrigerant in the system, only the temperature of what's in there. You can charge to the sight glass and get pretty close for the conditions at which you are charging, but your performance may suffer at other conditions. Biggest concern is overcharging, since that puts a lot of strain on the compressor, risking damage to everything immediately downstream of the compressor. Those things would be, in ascending order of importance, the drier, the condenser, the connecting hoses, and the wallet.

dr bob

Continuing after a lunch break--

The Jim Morehouse CD set has images of the workshop manul pages that give the system specs and capacities. It also has the factory AC system training manual that has lots of more generic tips and techniques. Worthwhile investment if you don't have one already. 928srus.com

Want to be

Very cool. Now...can you direct me to the correct link. LOL.

Most of the links talk about 134a converstion or advise of not going past the green marking. My gauge does not have any markings.

My guess its 2 or 2.5 lbs.

Speedtoys

Except the first link tells you in great detail...what you need to do, and the R12 data.

Want to be

awesome,

During lunchtime i could not view all of the links. "Company security"

Needless to say, viewing all of the links i found the number range i was looking for..

Low side should definitely be below 35 or 40, but not below 15.

Thanks

Speedtoys

Good luck. Pressures never worked for me.

Using a scale was nuts perfect first try.