kingston944

So I'm confused do I take pressure reading at 2000 rpm or at idle? Trying to figure out the pressures and it changes as I increase the idle. I pulled a vacuum for 1.5hrs . Then let is sit to see if it held vacuum it held vacuum. I then charged with 2 cans of Duracool blows cool during sunny days but not cold enough and in the night time nice and cold. The rad fans what speed do they run at when A/C is on ?? I also sprayed cold water on the condensor and no change.Thanks for any input .

joejoe

My '84 calls for 40.3oz r-12. Other cars are at the airport so cannot check those but should be same or close. 2 cans would be 24 oz (assuming 12oz cans) so you may just be undercharged. I have not used duracool however so there may be some conversion factor involved.

The only other product I have used is called autofrost. It required 80% of regular charge. In a non leaking system it is very good as I found pressures lower and as cold (if not colder) that r-12. When charging I run car at 1800-2000 rpm. I charge my cars by weight (I have acquired all necessary equipment for a/c work except gas analyser) so exact amount is put in.

Both fans should run at full speed when a/c is on.

Again with duracool I have no experience but normal with r-12 should be 30 - 35 low and 180 - 210 high (what I have seen during hottest days in summer) Hope this helps.

V2Rocket

i just let it idle..

xsboost90

put the gauges on it and see if you can get it to around 20-22 psi on the low side....

pjg

Pressure will depend on outside temp, you need a manifold gauge set to check.

Check this link: http://www.ackits.com/aacf/ptchart.cfm

944Ross

I assume this is an R-134a conversion? You don't say what year your car is. Full charge on retrofits is about 80% of the R-12 fill. I've not been able to get below about 40 deg F evaporator temps regardless of ambient on both an Early and Late 944. I think a change in expansion valve and condenser would be required to do better. Does it really get that hot in Ontario??

kingston944

The car is 1987 n/a sticker says 33,5oz R12 which when using duracool is 2 cans. I have a manifold set and today I checked the pressures and at idle it is low side 59 high side 125 .Then increased the idle to 2000rpm and low pressure is 32psi and high is 195. I am using duracool 12a .If I increase faster then 2000rpm the pressure changes as well I realize that the pressure changes with ambeint tempertures.

kingston944

Compressor week???

944Ross

From the Duracool website:

"To replace CFC-12 with DURACOOL 12a® requires the removal of all existing refrigerant. Charge the DURACOOL 12a® using 35% of the original (CFC-12) charge weight listed on the system tag. eg; system tag calls for 40oz of CFC-12, use 14oz DURACOOL 12a®. Since DURACOOL 12a® is compatible with the mineral oils there is no need to change or flush your system. DURACOOL 12a® will work with the existing components. Pull a vacuum to at least -10 in hg. If a vacuum pump is not available be sure to use Duracool® DuraDry™ to remove system moisture."

You are way overcharged if Duracool comes in 12 oz. cans, you should only need one can (33.5 x .35 = 11.7 oz).

kingston944

So if the correct amount of R12a is in and the pressures are what I have then what compressor? Help anyone ? Would like to get it working.

944Ross

Duracool is propane, not R-12. Did you bleed off some of the Duracool?

CurtP

Which version of Duracool did you use? There's two. A non-DOT compliant version which is a flammable blend of hydrocarbon (propane and butane) and 134a. The DOT compliant version has not been SNAP reviewed. I wouldn't use either one and recommend against them.

What did you use to evacuate your system? Did you replace the dryer?

And you take the pressure readings at idle. Did they supply you a temperature/pressure chart? Ambient temp readings should be taken 2" in front of the condenser.

kingston944

I use a robin air vacuum pump to evac that I hooked to the manifold gauges . I used duracool with oil chill . My friends gagare volvo has been using Duracool hydrocarbon for years works great. I have also used it for years evac and filling other cars but just not sure why the porsche is not cool enough. I did not replace the receiver dryer but did evac for 1.5 hrs which I have heard dry's the dessicant in the receiver. But for the price I don't mind replacing it. I have no ambient temp chart but if thew system is empty it takes 2 can of duracool 6 oz in each can.

944Ross

So it appears you have the correct charge, your compressor works, about the only reason I can see is a bad expansion valve or a plugged drier. I couldn't find any P-T charts for Duracool. I wouldn't use it either, but once it's in the system you don't have many choices, you're pretty much committed to it.

kingston944

I will buy new dryer and expantion valve and start there then, thanks for you input.