MFranke

Suggest not using adapters that depress the Shrader valves. Use adapter where you remove the old valve

bureau13

This is the one area (so far) where I declared defeat and took it to a professional (sort of....there were some issues with that too, see previous threads). I had already replaced o-rings, compressor and expansion valve, but had no equipment to do proper leak detection. They found one of the lines was leaking and rebuilt it, a few hundred bucks and it's still working. Unless you have experience with AC systems and leak detection equipment, that might be a good move for you as well. Just try to go with a shop that is reputable.

AirtekHVAC

Seth, I recommend you take it to a shop and have it leak checked...it won't cost that much, and at least you can pinpoint the leak....most garages have a machine that pressurize, evacuates, and recharges all while you watch...of course it won't fix a leak....if anything, don't put any stop leak in it....only bad things will come of that.....or...you can dump gas in it and get through SITM....I will be back to full staff in July, and will have some time...we can pressurize with nitrogen and check her out...I don't think you are more than a few hours from me.....

skpyle

dr bob: Thanks for the advice. After looking through PET and a few AC posts, I did not see anything out of the ordinary. I believe the issue with AC in a 928, or anything in a 928, is space and access.

I am hoping like hell that the compressor is OK. A new one is something like $2400, 928 International doesn't list any good used ones for 1986, and even a new 'Kuehl' compressor from Griffith is $800.

Will do on the compressor heat shields, thanks!
I figure the fuel cooler will be 'entertaining' to deal with.



Imo000: Nope, honeymoon is still good. I expected issues with the Red Witch sooner or later. It is what it is, she is a 30 year old used car. I am not phazed at all. Though, my credit card is uncomfortably warm...



WyattsRide: Why? I thought rear AC made for better cooling in the car. I will get it figured out. Can and will do.



Speedtoys: I am not looking forward to this job, but it is what it is and must be done.



The Forgotton On: Yeah, I am going to do it right. We shall see about the HVAC box...



MFranke: Sorry about the confusion. I am not referring to the retrofit R134a adapters that screw onto the existing R12 ports. I am referring to the female quick connect adapters for my manifold gauge set that connect to the R134a male quick connect adapters. Please refer to the first photo. Follow the red hose down to the high pressure fitting, not the red anodized connector.



bureau13: I am not sure about a professional shop right now. I am not sure if there are any reputable AC shops in Gaffney, let alone one that will touch a 928.

However, there is a little hole in the wall repair shop that caters to European imports in Gaffney. Owner is familiar with 928's. I will contact him and see if he can do a leak check. That is my main concern right now. Is it a leaking O-ring or seal, or have I popped a line or compressor? I need to know.



AirtekHVAC: Ron, I am taking your advice and going to have a shop do a leak check. We will go from there. I think the leak is significant enough that a recharge won't make it through SITM.
Oh hell no on stop leak! I avoid that like the plague.
Thanks for the offer of help. I may very well take you up on it. We shall see.



I have sifted through the receipts from the PO. I found an invoice for an expansion valve, low pressure switch, misc seals, and 3lbs of freon, all dating from 2001. I don't think this is the retrofit.

Anyway, it is all so old that I am going to go in and do a re-retrofit. My above shopping list still stands. The only hiccup is the oil. I will contact the PO and see if he remembers anything.


Seth K. Pyle

griffiths

Seth,
Leak wise, the common leaks are compressor seals, hoses at compressor, a schrader valve core, and if you have rear air ... the rear evap core, and occasionally o-rings at the expansion valves. Sharks with rear air can be a pita, besides issues with the evap cores leaking the solenoid valve can get hung up (not fully closed) and refrigerant oil gets trapped in the back section (killing the compressor).

The typical procedure to find the leak is to pull a vacuum, charge with R134a, sniff with an electronic leak detector. You could inject a refrigerant dye and poke around with black light however electronic leak detectors can sense leaks where you can not see them.

If you have a local near by that has a vacuum pump that could save a few bucks in buying equipment you wont' use often. Electronic leak detectors can be found used or you can buy an inexpensive one and resell it when you are done.

Another option is to find a local shop that has AC equipment (recovery, evacuation, charging, electronic leak detector) and ask them to quote you:
evacuation, charge, test and sniffing with the detector, and identifying the leak. You do the rest of the repair.

A typical R134a conversion involves: new drier, new o-rings for the system, ester oil, R134a charge port adapters with their own schrader valves, refrigerant identification stick. If you have the stock compressor you could do a tear down, inspect the piston rings, cylinder bores, wobble plate, reed plates, shaft seal contact area on shaft. If all looks good toss in a new compressor seal kt.

When inspecting the system if you find debris in the refrigerant oil (metal particles, excessive 'black or grey' matter, congealed refrigerant oil, you'd liquid flush the system with refrigerant flush (you don't flush driers, compressors or expansion valves; you'd remove the expansion valve from the evap's), blow out with shop air. A few cans of Interdynamics - A/C System Flush. Part #: CA1.

Avoid using any product that contains a "sealer". AC sealants can cause more headaches.

We have converted many sharks to R134a with the original R12 expansion valves and they blow cold; the difference is superheat is negligible.

bureau13

Regarding compressors, I got a rebuilt ND from Roger for a very reasonable price...hopefully you don't need it, but if you do, check with him.

Alternatively, there is a thread on here where someone rebuilt their compressor themselves.

mdkelly1

There are good updated conversion kits available. Installed a Griffith's R134a conversion kit (which included a new compressor) in 2001 and it's still working fifteen years later.

dr bob

I'll second Griff's recommendation on using an electronic sniffer vs the dye method. The sniffer gives rather instant results, where the dye method requires that you thoroughly clean around every connection, run the system for a while, then go hunting for dye traces with a blacklight. Many connections aren't visible under the best circumstances. The dye seeps out in any oil that comes through the leaking parts, and that can take a while.

I waste no time fiddling with the dyes. I suspect it's a lot like the doctor who can't quite figure out where your problem is or what it is or what to do about it. So he sends you down the road with "throw two aspirin in the tank and call me next week if the condition persists". He has your money for the visit, gets to charge you again if you do come back, and sells you more refrigerant and dye each time.


-----
Related:

My car came to me at about 8 years old but with only about 20k miles on it. Came with every piece of paper ever involved with the car, including the handwritten offer sheet and a copy of the buyers purchase check. And a couple inches of dealer service receipts and work orders. I hit the gold mine! Then the AC funked. So I recharged it. A month later, it was falling off again. Start cruising through the gold mine of receipts, and discovered a traceable history that included AC service orders since the car was new. "Inspect for leaks. None Found. Evacuate and Recharge." By the time my third recharge was required, I'd gathered the parts and pieces to do the whole reseal and conversion. Note that I had plenty of R12 stockpiled, but decided to try R-134a anyway. Figured that if I used POE oil, I could easily go back to R12 if the system performance wasn't adequate. It's been fine. Point is though that the car was leaking from the time it was built and sold. Genuine Porsche Factory Equipped with leaks.

skpyle

griffiths: Thank you for your advice! I very much appreciate it.
I have browsed your website, getting ideas. I do have a question:
I see you have R134a conversion kits and ND compressor seal kits, but I did not see a full AC system O-ring and seal kit. Did I missed it or do you not offer this?

My intent is to go tomorrow to a local shop that is familiar with 928's. If he doesn't do AC work, I am hoping he can direct me to a local shop that will work on a 928. I want the system to be leak checked with a sniffer.

I am reasonably competent with automotive AC. I have a set of gauges, adapters, a good vacuum pump, etc... I do my own work to a point. I will have a shop determine what is leaking, then do the repairs myself. My intent is to replace the wear items and go from there.

I am hesitant and nervous to go into the AC compressor. I am going to have to research how to do this.

I am familiar with AC 'Black Death'. That means the job goes from a (relatively) simple seal/O-ring/component replacment to a flush everything and replace the compressor and condenser, if not the evaporator. Yikes!!!

I take Nancy Reagan's 80's drug advice for AC sealers: Just Say NO!

Good to know about using the R12 expansion valve, thanks!



bureau13: That is definitely good to know, thanks! I will keep that in mind.



mdkelly1: I saw the updated kits on griffiths' website. That may be a possibility.



dr bob: Good advice, no dye for me. I am going to find a shop that will do a sniffer test.
Ouch...bitter pill to swallow on your 928. Good to know that you have had a good experience with R134a. The Red Witch cooled OK while refrigerant was in the system. I believe it will be nice and cold once I get done going through everything.


Thanks again for all the advice!

Seth K. Pyle

dr bob

Edsel Murphy strikes those who gloat on their long-term success. Looks like I'm replacing the front expansion valve next week.

skpyle

Ouch. Sorry.


Seth K. Pyle

skpyle

Found out today that the little import shop is closed on Friday's.

However, my machinist has a sniffer. I will borrow it Monday, charge up the Red Witch, and go looking for leaks.

Now that the Liftbars have arrived, I can get her up in the air for a peek underneath.


Seth K. Pyle

griffiths

Our R134a conversion kits include a full system o-ring kit.

We sell a separate compressor seal kit, hoses, drier, certain condensers and evaps.

We attempt to market what is most commonly needed for
DIY procedures; however we do not market just a system o-ring kit alone or
individual o-rings. 90% or more Shark clients are converting to R134a or replacing compressors and hoses; hence you will see the product selection is directed in that fashion. For individual o-rings probably Pelican parts, Porsche Dealer or local auto parts store.

Glad we could offer you some help.

Enjoy the weekend

Jfrahm

For what it's worth I am using R152A to replace the R12 in my 1992 968, and it works very well indeed. You get a can side-tapper off Ebay or wherever and cans of computer duster spray Aero Duster, from wherever. I got some from Walmart. My 968 took 2 cans and I had some left over. Check Youtube for vids if you need more details.

I recommend safety glasses and non-absorbent gloves when working with R152A, it's no big deal but I did soak some into my mechanics' gloves and they got pretty cold.

For the 928 I also run an aux relay down by the compressor to take the electrical load off the climate control head relay. This is easy to do, you wire up a foglight relay to the compressor clutch wire and power the clutch via a fused wire from the jump terminal. Way cheaper and easier than the other fixes.

-Joel.

skpyle

griffiths: Thank you! That makes sense. The more I look at what I am getting into, the more I believe I will 're-convert' the system to R134a: new hoses, drier, fittings, schrader valves, O-rings mainly using one of your kits.
I'll know more once I track down the leak.


Jfrahm: Thanks for the heads-up on the refrigerant. I am definitely doing the clutch relay mod.
Thanks!


Seth K. Pyle