A/C help needed

In the top picture I assume that inline filter is on the suction side just before the compressor?

What is that yellow thing T'd off just before that filter?

In the bottom picture is that red thing some kind of relief valve?

87-944S wrote:Here's some pics, the cylinder with blue ends is an inline filter with compression fittings.
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acorad wrote:In the top picture I assume that inline filter is on the suction side just before the compressor?

What is that yellow thing T'd off just before that filter?

In the bottom picture is that red thing some kind of relief valve?

87-944S wrote:Here's some pics, the cylinder with blue ends is an inline filter with compression fittings.
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Yellow one is probably the high pressure switch. The red one is the service port for filling, draining or checking the A/C System. red is typically high pressure side Blue Low Pressure side.

Thanks Dawg, I'm using the existing Porsche drier, and I believe it has a high pressure switch so I guess I don't need to put a second one in.

I assume that in-line filter is a good idea to install.

I wonder if there's a more accessable place to put the service port...

acorad wrote:In the top picture I assume that inline filter is on the suction side just before the compressor?

What I've been reading is that an inline filter should be installed in the liquid line after the condensor and before the evaporator.

Normally an additional filter is installed if you burn the compressor out. This goes in the suction line. It keeps any floating particles from destroying the new compressor.

In commercial and industrial systems, refrigerators and air conditioners you put a small filter/drier in the liquid line. This is done to trap any small particles that got in the system during assembly to keep them from getting into the expansion device. Small systems like refrigerators and window air conditioners use a cap tube (very small diameter tubing) as an expansion device and these especially can get plugged from debris from assembly.

Cars use filter/driers for the purpose of removing small amounts of moisture and other non-condensables from the system. Cars generally do not get as high of vacuum when evacuated so they use a much larger one than you would see in most other refrigeration systems.

It is a good idea to add one if your air conditioning has been open for a long time. It is generally not necessary if you haven't driven your car with open lines or had the car with an open system in a very dusty environment.

When you get the A/C working make sure to post pictures of the hoses and fittings. I just connected the wiring to mine over the weekend.

V8, do you think my compressor is cleanable? Or should I buy a new one?

If it is cleanable, how should I do it?

here's a tutorial to clean the system...

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some good info here as well...

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Arthropraxis wrote:When you get the A/C working make sure to post pictures of the hoses and fittings. I just connected the wiring to mine over the weekend.

Will do.

944convert wrote:
some good info here as well...

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Thanks!

Question: When I flush my system, can the compressor be flushed too?

Answer: No, not with typical solvent flush methods. The compressor should be removed from the vehicle and the oil drained from it. You can pour refrigerant oil into the suction port and turn the compressor hub by hand which will pump clean oil through the compressor. Remember, compressors don't compress liquids. So, make sure you rotate the compressor hub by hand enough to ensure you don't liquid "slug" the compressor.

Arthropraxis wrote:When you get the A/C working make sure to post pictures of the hoses and fittings. I just connected the wiring to mine over the weekend.

Gotta say, the more I look at the pics of 87-944S's setup, the more I like it.

I think I am going to do something like that too. It will be even easier since I don't have to use the pressure port.

If your compressor has black death, replace it. If it has just been open because of hoses not being connected, you won't have much to worry about. You just need to pour out the old oil and replace it. Do this just before you close up the system and pull a vacuum. All oil for R134a is hygroscopic. (absorbs moisture) Don't use PAG oil. The OEM does because it it cheaper but PAO is better. PAO also will not cause any problems if you have any components that had mineral oil in them. (R12 parts) PAG doesn't get along with mineral oil well.

Arthropraxis wrote:I think I am going to do something like that too. It will be even easier since I don't have to use the pressure port.

Yes, there is an existing high-pressure port by the driver's shock tower. Any reason to have an additional port on the low-pressure side?

v8carreragts wrote:If your compressor has black death, replace it. If it has just been open because of hoses not being connected, you won't have much to worry about. You just need to pour out the old oil and replace it. Do this just before you close up the system and pull a vacuum. All oil for R134a is hygroscopic. (absorbs moisture) Don't use PAG oil. The OEM does because it it cheaper but PAO is better. PAO also will not cause any problems if you have any components that had mineral oil in them. (R12 parts) PAG doesn't get along with mineral oil well.

Great info, thanks!

The only reason to add that port is for the GM ECM. If you have the A/C and fans controlled by the Porsche system, it should not be needed.

Arthropraxis wrote:The only reason to add that port is for the GM ECM. If you have the A/C and fans controlled by the Porsche system, it should not be needed.

Thanks!

Since it's easiest, and seems to work fine, I guess will be using the P system for the A/C, which includes a high-pressure port & switch by the drier.

The port I mentioned in my previous post is a service port on the high-pressure side.

I think I may add a low-pressure side service port now anyway, just in case I might want/need it in the future.

The fan is controlled old-style, a relay turns the fan on and off depending on radiator temp. I hope that'll control my engine temp OK when the A/C is running.

Sounds like you have some re-wiring in your future.... Ask Arthropraxis how he wired his fans to work with the GM ecu and porsche AC.

spence wrote:Sounds like you have some re-wiring in your future.... Ask Arthropraxis how he wired his fans to work with the GM ecu and porsche AC.

Spence, I'm not sure what you're saying.

Are you saying there will be a problem with the way I'm currently running my fan after I get my A/C up and running? What is the problem you see?

The fans are susposed to come on when the a/c is running. With the way you have it wired now the fans will not come on when the a/c is on.

Arthropraxis used the existing porsche fan relays / wiring; so when he turns on the a/c the fans will come on too. He used the old thermoswitch wires and hooked them up to the GM ECU's high / low speed fan wires. This way the fans are controled by the ECU and the a/c when turned on from in the car will turn the fans on too.

I really don't know if the way you have it wired now will be a problem?

spence wrote:The fans are susposed to come on when the a/c is running. With the way you have it wired now the fans will not come on when the a/c is on.

Arthropraxis used the existing porsche fan relays / wiring; so when he turns on the a/c the fans will come on too. He used the old thermoswitch wires and hooked them up to the GM ECU's high / low speed fan wires. This way the fans are controled by the ECU and the a/c when turned on from in the car will turn the fans on too.

Thanks Spence, that's probably the best way to do it.

With my setup the fan comes on when the radiator temp gets to about 180F or so, so I guess my A/C would be somewhat marginal until the rad heats up enough to turn the fan on. The rad does heat up fairly quickly though, and will probably do so even faster on hot days coupled with the additional load from the A/C compressor.

I suppose I can always change the wiring and have the GM computer run the A/C & fan if my current system doesn't work out.

Would something like this work at the firewall to connect to hose to?
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Or could the factory hard tube be flared and use an AN to O-ring adapter?

Has anyone looked into using a different (R134 specific) condenser? I'm going to be doing my system at some point here, but i'm not sure i want to bother trying to get a R12 condenser to work well with R134. Seems like it would be pretty easy to find something out of a small import that fits the bill and puts the ports on the passenger side (so that the lines don't have to be run all the way over to the driver side).

Porch wrote:I'm going to be doing my system at some point here, but i'm not sure i want to bother trying to get a R12 condenser to work well with R134.

What is the problem with the r12 condenser, are you thinking a bigger condenser would be preferred for r134?