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Anyone Have AC Exploded Diagram from Service or Parts Man?

 
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austinporsche  



Joined: 26 Apr 2018
Posts: 43
Location: Austin, TX

PostPosted: Thu Jun 27, 2019 4:58 am    Post subject: Anyone Have AC Exploded Diagram from Service or Parts Man? Reply with quote

Hi all.

Having bought a 1988 924S almost 2 years ago, then putting it into storage, I have finally taken it out to drive it.

First, among my running 2 seaters (911T, RX7, X19, 928), let me say that the 924S is already my favorite. Ergonomically, everything is where it should be, the engine pulls stronger than its 158hp would indicate, the gear spacing is right on and the handling is very neutral and predictable. Would it be presumptive of me to say the 924S is perfect?

Problem is that I live in Texas, and without working AC, the car's use is limited to 3-4 months -- and I want to make this into my daily driver.

I am pretty good at AC basics. OK, more than basics, I have replaced compressors, condensers, accumulators, expansion valves, hoses and even evaporators (the worst job ever), flushed systems, done full vacuum pump downs and refills, etc. I have all the tools.

In most all other cases, I haven't even needed a schematic to figure out the flow of things, but the 924s has me a bit befuddled.

I have the Haynes 944 manual (I have 4 944s, none running, all waiting to be restored -- there is no 924 only manual correct?), but the Haynes 944 AC section is pretty useless save for the electrical schematics for the AC. (Even that schematic is confusing to me; for example, what is the air conditioner supplementary air valve?)

So first question is whether anyone has a proper service manual or even parts manual that shows an exploded view of the AC system so I can sort things out, like where the expansion valve is (I am assuming since it is not at the firewall, that it is inside the cabin with the evaporator).

Second thing is figuring out the high and low sides. There are two ports I found: one at the firewall and the other at the receiver/dryer. The one at the firewall has an R12-to-R134 low side quick connect adapter on it, and both port have blue caps (2 low sides? me thinks not). The blue cap on the port at the receiver/dryer notwithstanding, am I correct to assume the port at the firewall is the low side?

I got the gauges out (my R12 set; I also have an R134 set so I can keep the oils separate without having to clean it every time I move from a 12 system to a 134 one), connected to the firewall adapter and pumped in Redtek R12a (that bridge refrigerant that works in both 12 and 134 systems: great stuff when you are unsure whether an original 12 system has been upgraded to 134).

It gets up to 30-40psi, then I can hear a hiss as the pressure drops to 10 or so over a few minutes: clearly there's a leak in the hoses running along the firewall or (dreaded) in the cabin behind the dash. (dash is cracked and needs to be renewed anyhow).

It is tight as heck and like spaghetti there at the firewall, and one one to/from the evaporator has a fitting on it while the other doesn't, so again an exploded view of how all the plumbing is routed would be most helpful to get me on my way.

Thanks in advance for any help.
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PaulD_944S2  



Joined: 25 Nov 2014
Posts: 9
Location: RIverside, California

PostPosted: Sun Jun 30, 2019 12:58 pm    Post subject: AC 101 Help with the 924S Reply with quote

I'm reposting this from Pelican Forum:

First, go here and download the workshop and parts manuals, drawings will help you sort out locations and part numbers:

Porsche 944 manuals - Free download

There is a lot of things to know about automotive air conditioning systems, but you appear to have knowledge and I'll leave it at that.

Having said that, here's my help in a condensed form:

For the leak, start with a visual inspection of the hose from the compressor to the condensor, it's the most stressed part. Look for oily parts where leaks are. Replace the O-rings at the hose fittings if you open it.

If you see any debris, metallic particles, or anything other than refrigerant oil in the system, please flush the system thoroughly so you don't wind up doing the work over again.

Best setup is to pull compressor and drain oil out, add 2-3 ounces of POE (POE will mix with mineral oil (R12 oil) and DON'T use PAG). Replace the drier and add 3-4 ounces of POE to it. Be sure to hand rotate the compressor in both directions several turns after adding the oil so you don't lock it up. Use new O-rings at hose block.

Evac the system properly, and add R134a to 80% of the oil volume in ounces that R12 system uses, or if you are experienced, use your gauges to go by temperature and pressures. Don't overfill with refrigerant, less is better. Add refrigerant slowly to allow it to mix and distribute the POE oil. There are You-tube videos if you want more info.

Seeing less than 45 degrees out the middle dash vents with the fan set on mid speed is easily doable. Typical can be 38-42 degrees at 2500 RPM.

Good luck, take your time and do it right!

If you need hoses or other parts, or a good guy to talk it over with, call Charlie at Griffiths:

https://griffiths.com/porsche/air-conditioning/924-944-951-968/

And here's a link to practices in MVAC:

https://griffiths.com/warranties/
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PaulD_944S2  



Joined: 25 Nov 2014
Posts: 9
Location: RIverside, California

PostPosted: Thu Jul 04, 2019 2:22 pm    Post subject: Reply with quote

Your original post has me confused.
You are chasing a bad relay under the dash and guess the control knob isn't working, but you state that when you added refrigerant, you could hear a hissing noise and the refrigerant pressure went down.

Clearly, you have a leak you need to repair.

It will be difficult, but follow the hose from the compressor and condensor along the fender well and firewall to where it goes through the firewall to the evaporator. Look, or feel, for a presence of oil along the lines.

Somewhere, if there is a leak in this area as you state, you will feel an oily spot, most likely where the rubber hose is crimped to the hard line, or the rubber hose is broken through the outer jacket.

Since you don't state you have a refrigerant leak sniffer, this is the only way you can find the leak.
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austinporsche  



Joined: 26 Apr 2018
Posts: 43
Location: Austin, TX

PostPosted: Thu Jul 04, 2019 10:19 pm    Post subject: Reply with quote

Paul is right on.

I have been stupid/confused/lazy in my approach so far.

Here's the update.

I finally got organized and put a multimeter to the harness, and I do not appear to have an electrical related issue.

The electronic box behind the glove box and referred to as an "amplifier" in schematics is putting out 10v to the pressure switch when the AC fan switch is on. Hopefully that is enough to energize the clutch (more on the clutch in a moment).

I tested the continuity of the wire from the pressure switch to the compressor clutch and that too is good. (Assuming for the moment that the pressure switch is good -- they're only $10 anyhow).

I then put 12v directly from the battery to the compressor clutch power wire and no "click", i.e., no energizing of the clutch.

So problem 1 appears to be the compressor clutch.

Next I put the gauges back on it.

I was sloppy/stupid the last time, and I was only getting a 40psi reading because I had a refrigerant canister hooked up to the gauge manifold at the same time -- duh.

Without the benefit of that little pressure helper, the system is not holding pressure.

As a vacuum won't help me with the leak (without a compressor to push around dyed-laced refrigerant pumping it down makes no sense, to me at least), I made an adapter that allows me to put 40psi of positive pressure from my compressor into the low side port.

When totally quiet in the garage, I can hear a hiss.

It appears to be toward the front of the car. So not at the evaporator -- though it may be at the other end of one of the two evap hoses, which means tackling the evap connectors: finger crossed it isn't this. If it is one of these two hoses, then I still need someone to answer my question about how to access the hose-to-evaporator connectors: from the glove box, by removing the whole dash, going thru the fresh air blower hole on the engine side of the firewall, or some other way?

The leak doesn't appear to be on either end of the receiver/drier either -- which is original and still even has red paint dabs on the dry (no oil) connections from the factory. So hopefully that eliminates the receiver/drier-to-evaporator hose.

So now I've got to jack the car up to see whether the leak is at the compressor-to-condenser hose, the condenser-to-receiver/drier hose (don't think it is this one) or the evaporator-to-compressor return/suction hose. Or the compressor itself.

The good news is that I realized is that once I sort this all out, I actually have four (4) 944s that I could temporarily cannibalize for a compressor or compressor clutch or hoses.

Don't even ask, over past 3-4 years I have collected four non-running 944s -- three given to me by friends that wanted them out of their garages and one I picked up at auction from the Houston flood a couple years ago for $500 -- some day, I hope to put together 2 or 3 running 944s out of them. And yes, I actually had this epiphany as I was sitting there on my shop roller stool looking forlornly at the red 924S and wondering where I was ever going to get hoses or a compressor -- with a mist green 1986 944 sitting right next to it buried under a bunch of stuff I've stacked on it over the years.

So once I solve the compressor clutch and leak problems, I am going to flush the system of mineral oil (the OCD in me loves flushing AC systems), put in a new receiver/drier and either follow Paul's advice and do the Porsche bulletin upgrade to R134 or just fill it with R12a (miracle stuff as it worked great for me on an '82 RX7 I have that also had a non-working AC).

I see a light at the end of the tunnel.
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austinporsche  



Joined: 26 Apr 2018
Posts: 43
Location: Austin, TX

PostPosted: Sun Jul 07, 2019 1:06 pm    Post subject: Reply with quote

OK, I have AC!

Fortunately, the leak was at the compressor-to-condenser hose o-ring and not in the hoses themselves.

The compressor clutch was also bad, so I swapped out the compressor with one from a 1986 844 I have.

(I plan to try and rebuild the compressor with the bad clutch with a rebuild kit from the Griffiths folks mentioned by someone earlier in this thread and a new clutch from eBay).

With the "new" compressor installed and new o-rings on the hose fittings, I resisted the urge to flush the whole system and install a new receiver/drier and instead just pumped it down, and it held vacuum. Hurrah.

I then refilled with 12 oz of Red Tek E12a (the equivalent of 36oz of R134 as 35oz is called out in the R12-->R124 conversion service bulletin), and I now have AC.

Grateful I never had to figure out to get to the evaporator connectors.
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ted von Kampen  



Joined: 14 Oct 2016
Posts: 127
Location: Scottsbluff, Nebraska

PostPosted: Sun Jul 14, 2019 3:29 pm    Post subject: Exploded view of compressor Reply with quote

Did you ever find one? I am looking for one for my Denso 6P134 which is on my 1981 Porsche 924. Let me know if you know where to find one.
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ted von Kampen  



Joined: 14 Oct 2016
Posts: 127
Location: Scottsbluff, Nebraska

PostPosted: Mon Jul 15, 2019 4:11 pm    Post subject: Exploded views for compressors Reply with quote

I found a 500+ PDF catalog from Santech industries that has many exploded views of various compressors. you can search for them but if you cannot find the link to view, PM me and I will send you a copy of their catalog. In additions to the diagrams, they have pages of parts for Compressors. A valuable resource for sure. ...Ted
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Goldwolf  



Joined: 25 Jun 2017
Posts: 193
Location: Athens,GA

PostPosted: Sat Aug 03, 2019 2:25 am    Post subject: Reply with quote

I just called this company. The don't have the units in stock but will send to have them rebuilt for $241 clutch and all. Your unit has to turn is the requirement.

https://www.ackits.com/comp-6p134-8ears-1a-grv-12v-remfg-4009
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