Conor

I talked to a local Porsche shop about getting my AC recharged with R12, and they said it would be at least $200, thats if nothing else is wrong. SO, I've decided I am going to convert it to R134, and I'm gonna do it myself.
I was wondering exactly what I will need to replace. I did some searches and I am thinking some lines, o rings, and drier(not really sure what that is). Does anyone have a part list compiled of all the things that I would need? Special tools maybe? Also, how do you make sure all of the old oil is out of the system? I'm planning on getting some of that black light dye, to see if I have ant leaks.
Also, if anyone has any recommendations about where to get stuff/what it will cost that would be helpful as well.

TIA

Conor

Travis - sflraver

They sell a "conversion" kit at your local auto parts store. I have used it on a few cars and it works ok. Its cheap and has leak stop and oil in the r134a that comes with it. I just screw on the adaptors, and put a few cans in them.
Someone once told me, and I have taken it as true, that the reason it is so expensive to have a shop change it over is because they are not allowed to mix the different types (r12,134a). If there was a mix that would mean that it would contaminate the recovery tanks when someone tried to take it out next time. Thus changing everything that could hold little remaining bits of the R 12.
I dont know how true that is but its what I have been told. Changed the AC in the Porsche over by just putting in a few cans with the screw on adaptors. Works great now.

HY M8NC

The reason you need to replace the receiver/drier in your particular case is because of a leak. If you need a recharge in the system, it has a leak-generally speaking. The freon/oil mixture won't evaporate. To that end, when the charge is leaking out-air is leaking in. Moisture is a killer to this system. In an R-12 system it will create hydrochloric acid, in an R134a system it will create hydroflouric acid. The reason you replace the accumulator/receiver drier is because its job is to remove moisture from the system (contains a dessicant). If there has been air (moisture) in the system-the dessicant may be useless.

The only way to make sure the system is totally cleaned out is to flush it with an approved flush, and then draw the entire system into a vacuum.

Although they are not the "correct" way to do a retro-fit, I have heard of a lot of success with retro-fit kits. That might be your best bet.

Retro-fit kits from Interdynamics are popular, and i think they already contain dye.

The tech line at Four Seasons (Large Aftermarket Air Conditioning Supplier) is 888.819.4119. Call and ask them what you should/can do. It's free.

Conor

Thanks for the help guys! I'll give that place a call.

Anyone else?

Conor

Bri Bro

Why not go to another A/C shop and get a better price? There is nothing special about the A/C system in a Porsche. Any good A/C shop should be able to top off the charge for under $100.

Jay W

R12 top off for under $100 is unlikely unless you know somebody at the shop. Law requires a shop to fully evacuate a system and hold it at vacuum for 15 minutes to make sure it doesnt leak 'badly'. If it doesnt hold the vacuum the shop cant legally fill it because they now know it has a leak. This requires use of a recovery machine for 1/2 hour and a guy keeping an eye on it at least. Most shops are at least $50 in labor for this amount of time and R12 is over $50 per pound. An empty system has an average capacity of 2.5 pounds of freon. Now if you know a guy and he just tops it off and sends you on your way so you can avoid all that mess then..... But then when it all leaks out in 2 days you may be a bit upset because you just wasted $150 plus worth of R12 and nobody buys it cheap anymore, not even the shops...

thomschoon

Hate to admit it but went to Wally World (WalMart) and bought a retro-fit kit for $22. Followed the directions and it worked fine. I figure it really wont cost me anymore to fix it "right" if it breaks and I got at least one extra summer out of it.

Bri Bro

From : Technician's Study Guide
For EPA Section 609 MVAC Technical Certification
<a href="http://www.imaca.org/sg-12.htm" target="_blank">http://www.imaca.org/sg-12.htm</a>

Topping Off Motor Vehicle A/C Systems

Since the inception of the Clean Air Act, one of the most misunderstood rules applies to "topping off" motor vehicle A/C systems. Many automotive service technicians believe that 'topping off" (adding refrigerant to a known leaking system) is prohibited by federal law. Not only is this belief not true, telling a customer so would constitute consumer fraud. EPA recommends that all leaks be repaired prior to recharging an MVAC system. "Topping off" is allowable everywhere in the U.S. except where state or local laws prohibit it. Leaking MVAC systems must be repaired prior to charging the system in Wisconsin; the South Coast Air Quality Management District (SCAQMD), of California covering the counties of Los Angeles, Orange, Riverside and San Bernardino; parts of California and Colorado; Austin, Texas; Albuquerque, New Mexico and possibly other jurisdictions. In cases where local or state and federal laws address the same issue, if the local or state regulations are more stringent than federal regulations, local or state regulations prevail.
EPA requires that when adding refrigerant to a system, the refrigerant added must be the same type as that which exists in the system. Example - HFC-134a cannot be added to a system containing CFC-12.

83na944

I have a dumb AC question.

How do you get the charging hose on the compressor?

On my '83, the schrader valve is so close to the bracket, I can't get the hose screwed on there. Is there some trick? Is there a suction port on the rear of the compressor?

I sort of figured that the AC shops just charge it through the high side.

ACG

Try this:

<a href="http://www.griffiths.com/porsche/ac/porsac944.htm" target="_blank">http://www.griffiths.com/porsche/ac/porsac944.htm</a>

Bob S. 1984 Silver

Sad but true answer re: access to the valve on the compressor....very poor design...what happens when an auto manufacturer uses the first off-the-shelf compressor with little or no regard to future maintenance.

Being out here in AZ, A/C is critical. I have redone a few 944s. In order to convert the high side/low side fittings, there will be a bit of work on the low side. High side is no problem. You will have to get a 90 degree adapter and also grind away a portion of the alternator bracket. A Dremel tool works good for this. Do NOT remove the original valve until the grinding is done and the area cleaned up. You do not want aluminum dust in the compressor!!! The R12 in the system should be evacuated by a qualified shop as it is a federal offense to vent R12 to the atmosphere. No matter what a specific coolant manufacturer may say, R12 and R134a are incompatable. And, only one molecule refrigerants can carry the prefix "R". anything else is a blend. Some blends are comprised partly of flammable compounds.

Also, the probability of air being in a system with a small leak is negligible since the gas can only leak out to the extent where internal pressure and external air pressure are the same. As the differential goes down (internal pressure drops), the rate of escape of refrigerant decreases. I have seen systems in the junkyard that when the Shraeder valve was depressed, still had some pressure after years of sitting in a wreck.

Interdynamics has some excellent products, a number of which contain a sealant that should take care of the really small leaks. Also, when the system is evacuated, any moisture which could play heck with the internal orifices will be "boiled off" since water boils a less than room temp in a vacuum.

Massiveleaks of course will have to be addressed such as compressor seals and o rings. However, during the evacuation process it is a good idea to leave the system with the gauges attached for a couple of hours to see if the system holds a hard vacuum.

Since the valve is relatively close to the drive belt, WATCH YOUR FINGERS!!!!!!!

I cannot remember the exact charge the system requires of R134a. That info should be available on a number of sites.

Beab951 is spot on with his info. It's in the textbook!!

Hope this helps.

ErichCS

Time to wake up this old thread - boy do i love the search function!

Bob S - I ran into the same problem tonight involving the low side on the compressor. Where does one find a 90 degree adapter? With the straight adapter there was no way to snap on the hoses due to the bracket there. Do local places like auto zone etc carry these?

Thanks!

Erich

adie

Am I the only person who uses propane??? works well for me.

ErichCS

I have heard that propane is explosive under A/C system conditions. Although i do know people who have used it before...

So does anyone know of a fitting that'll work for the compressor and allow for easy charging of 134a?

Erich

97xray

Erich, I PM'd you.
You can borrow my slightly modified old school 90 degree hose anytime you like.