CaptainGSR

My AC does not blow cold air anymore.

The compressor seems to work fine (clutch engages when full cold selected/no wires unplugged).

I hooked up a cheap gauge to the low side yesterday, and was getting just under 9psi at 2000rpm. It was probably 65-69 degrees OAT.

The CCU seems to work fine, as I can adjust the temperature from hot to cold, and all the buttons work. It just gives me ambient air at full cold.

As usual, I cursed a lot, spent hours online, and then started taking things apart. Determined, I managed to remove the firewall, and found oil residues under the expansion valve. Obviously those seals are shot!

Here is my first question! If it was just a blown O'ring, would I still register pressure at the compressor low side? Could it be just air in the system being pressurized?

BTW, I did not use my ac for over 6 months. (I learned my lesson...)

Do you have any advice or info to share? I am new to this and don't have any proper AC manifold gauges/vacuum pump, or any way to test for leaks. I'll buy some if I have to.

I am learning as I go. I want to fix the problem myself, and then I'll take the car to a shop to get the whole system evacuated and properly refilled with a machine. Does anybody have a place to recommend? I am in south bay.

Cheers,

MarkD

Based on your description it is likely the expansion valve. If the system is not used for an extended period of time and it work PRIOR to it not being used, then doesn't blow cold (and you have ensured system is filled properly, compressor clutch engages, etc)... I'd bet on it.

Be sure to replace the Receiver/Drier at the same time since you have the system opened up.
Be very careful in seating those o-rings properly.

Also, be careful in running the compressor when the expansion valve has failed. This can overheat the compressor and damage it since it can cause lack of circulation.

mcfeeley1071

I am in the middle of an evaporator replacement having a little trouble. I am learning as I go as well, I picked up a set of manifold gauges for about $45 at a local tool store. I highly recommend a set to test the system before you put everything back together.

CaptainGSR

I am looking at gauges and vacuum pumps online as we speak.
I was not expecting that at all. I have 2 other cars that need work. I have a crazy list of things to fix...

Bummer...

MarkD

vacuum pump would be good... couple hundred $ buys a good home shop pump.
This give you the ability to pull a vacuum and see how long it holds... determines if there is a leak and gives you and idea of how large the leak is.

CaptainGSR

If I get a shop to refill the system, do I still need to add refrigerant oil in there, or would their machine take care of that?

CaptainGSR

Is a set like this good enough, or too flimsy?

http://www.wholesalepartsandtools.co...et-390-87.html

What are the min specs I should look for in a vacuum pump?

atcbi5

I would do the following:

Evacuate the system with a pump.
Pull vaccum for about 3-4 hours look for no leaks.
if no leaks found after fill up with one can of oil,
then fill with R-134.
Remember that our cars are a bit diff, on the low side and the high side.

MarkD

unless you drain oil from something there is no need to add oil.
Evacuating will pull very little oil out.
Too much oil reduces cooling efficiency.

Re. the vacuum pump, I bought this one and like it: http://www.tooltopia.com/index.asp?P...D&ProdID=30479

Specs similar to this will do the job. I think this same pump is seen under a variety of brands.

I am not familair with the set you posted the link to... but that is cheap! Not sure if it is too cheap... sorry, I can't help there.

V

Reviving an old thread. I have the exact same thing as described in the original post by the OP.

Here is the story. AC works fine, blows cold. I put the car to sleep for 8+ months (loong winter) and fire the car back up. The AC sounds fine and blows air in different modes of the fan. But there is zero cold air. Not even remotely cold. If it helps I found a small amount of oil (I think it was didn't remember to check very carefully) when I removed the transmission cover. I think it's the transmission cover, it's the plastic crate cover that sits roughly underneath where the AC is.

I assume my A/C system has dried out. I guess a refill won't do, I need to check the whole system to get to the bottom of it? I just read a bunch of threads on this and the more I read the more confused I get. Must be the terminology maybe, having english as second language. Any help much appreciated.

ToreB

Hi there Viggo, take the car to an A/C specialist and have the system checked for leaks and refilled with a little dye in it. That's the first rule of non-cold 993's. Second is often to replace the evaporator :-(
I'll help if there seem to be any electrical failures.
Cheers from Norway
Tore
www.ccu.tore.bergvill.com

V

Hi Tore, thanks a lot. Would you recommend taking the car to an A/C specialist rather than a Porsche dealer that specializes in air cooled Porsches? One of the two it will be! Appreciate your input

ToreB

Hi there, as far as I know the Porsche guys here in Norway often consult A/C specialists in this. That will probably be the cheapest way for you anyway.
Cheers,
Tore