DBYT

I just received the dreaded news from my independent Porsche mechanic that my a/c evaporator is dead and needs replacing. Can anyone recommend an online seller of these, as the official dealer price in HK is close ot US$900 just for the evaporator!!!

Also, should I replace it with an OEM or something like a Griffith Serperntine evaporator?

Finally, does anyone know if there is any difference in a/c parts between a lefthand drive 993 and a right hand drive 993.
Thanks in advance
Darren

DBYT

Before I get told by people to search, I already did but did not find anything that answered my question.

glennp_993

If you are interested, I have one from my 1996 LH drive 993.

DBYT

Having read through the numerous threads on AC issues, I am now wondering if it is really an evaporator problem. The shop is saying that I need a new evaporator, new expansion valve, and new lines. AC has been fine with no issues at all and then a few days ago, it just stopped blowing cold air...only hot air. Took it to the shop, they checked the gas and said there was no freon and filled it up. Worked fine but 2 hrs later, hot air only.

Any ideas on the cause? Anyone else experience this sort of sudden death of the AC?

geolab

Please try the big snowflake on and open the engine lid.
Is the ac compressor clutch engaged (turning)?
If not, it could be the evaporator inside temperature sensor, cost $40.
Check and give me the answer please

DBYT

Geolab,
I will do it tomorrow when I get the car back from the mechanic and let you know.
Thanks

BS911

If the evaporator blew, then you would see refrigerant mess all over it most likely - or underneath the car. Under the front hood, pull the cover to the pollen filter, remove the filter, and look inside with a flashlight down at the evaporator. You might see where the refrigerant went - at least if it is outside the front of the evap.

There was an amazingly good, graphic, frightening, and thorough DIY done a few months ago for an evaporator replacement. As someone said... the 993 was basically built AROUND the evaporator so a replacement is MAJOR work, aka major labor, aka major $$$.

Just on principle: The shop said you need a new evap, expansion valve, and lines. My question is: WHICH ONE. All 3 didn't blow. If the evap blew, then tell me why the lines need replacing? If the lines blew then tell me why the evap needs replacing. Because they said all 3, my first thought is that they are trying to get you in the door for service you don't need - even if one of those 3 is actually service you DO need.

Could you verify that there is, in fact, NO gas in the system? (Even if by only depressing the service port needle and seeing that no refrigerant exits the system.) Now lets say you had a blockage on the liquid/low side of the system, then you would have a possible need for replacing one of either the evap, expansion valve, or related lines with very little way of determining which one. That would manifest itself in very low or zero low side pressure, but normal or excessive high side pressure. But if you are at a complete loss of refrigerant, then you should be able to tell exactly which part needs replaced.

Maybe I'm just paranoid though.

geolab

Hello Brian,
I am not stealing the thread but needed a quick advice.
My A/C did not blow cold air in June, so bluntly had 825 grams of 134a injected in the system.
The guy at porsche dealer told me the car had freon and oil levels is good but changed it for free.
I came back home and hooked the PST2 and found error "evaporator temperature sensor".
read the live values and the sensor was stuck at 128 degrees centigrade.
42 euros later and the A/C worked excellent.
Two months later, I hooked the PST2 for nothing, and found error P045 "inside temperature sensor motor"
Read the Porsche proceedures for the fix, and it says to check the CCU fan if working, and the temperature sensor inside the CCU.
I took out the control unit and the tiny fan was working great.
The temperature sensor too is working great. Checked it with an Ohmmeter and through the temp ****. The mixture is great.
All is working excellent, but still get the P045 error, any ideas?

DBYT

Brian,
Thanks for the input. After reading all your previous posts on the topic in the archive, I am convinced that there is no need to replace everything the shop is saying. I will check the car when I get it back later from the shop but am not convinced there is anything wrong with the evaporator. I have not had any leakage under the car etc. Will have a good chat to my mechanic this morning to find out why he thinks all those parts need replacing.
Thanks again.

BS911

DBYT - I hope you get to the bottom of things soon. Just shout and I'd be glad to help and share any experience.

geolab - I'm stumped on that one. The inside temp sensor would pretty much determine if and how much of the air mixtures to set on hot or cold(fresh). On blue dot, that temp sensor is kind of irrelevant and things should default to full cold anyway. Are you getting HOT heat on the first bump off of the blue dot per chance? If all temp settings and vent outlet temps seem normal then it might be just fine. So the ccu is saying that it can't read the motor, so I'm not sure what to make of it. Here is what the book says:

If your motor is turning then there could be a short or cracked wire headed back to the ccu to tell it is running. I'm not sure if the fan motor has a way like a computer fan to relay back rpms, and it isn't on the electrical diagrams anywhere either. Whether or not the computer knows it is running could also be irrelevant as long as it is getting the right temp from that sensor. Theoretically, if the fan weren't running then it would take forever for the sensor buried inside the ccu to know what the cabin temp has changed to. So it might be about as useful as the brake wear indicators. It doesn't affect operation - just tells you when something is amiss and would let you know why the "automatic" portion of the climate control isn't working.

Anyway, it could also be that it is simply a stored code from prior work. Just for giggles...

If you clear the code, does it come back? How does the a/c and heat work otherwise?

DBYT

Just spoke to the mechanic and he said that when he recharged the system, he could hear hissing from the evaporator and also could smell freon from the inside vents in the car. Said he checked the expansion valve and the drier too and all were bad and needed to be replaced. I am very tempted to get a second opinion. Like you guys have all said, it should be one thing or another, not all the bloody components!

Ron

If your car is leaking freon that quickly the leak should not be difficult to identify. While I have not done a Porsche evaporator I've done many evaporator replacements on Mercedes. Actually, it's not the freon that smells, it's the oil and it's quite nasty. I would think you might notice the smell when you drive.

The mechanic should have put in dye with the freon so you can find the leak. I'm not sure where the drains are on the evaporator case for the Porsche, but with a bad evaporator leak the oil with the dye will be visible at the evaporator drains.

When I replace evaporator I always use new reciever/dryer, new expansion valve, actually the evaps I use are ACM and they come with expansion valve.

Edited:
A Behr evaporator for that car costs about $480. Most shops mark up the price of part a whole lot.

Mark Wilson

DBYT - you need a second opinion. Thought my evap was bad this summer. Turned out the expansion valve was the problem. Much easier fix. There's no way he could diagnose without taking it apart.

DBYT

Mark and Ron,
Thanks for the advice. I have ordered a new expansion valve and will get them to replace that and see what happens from there. If it still does not hold the charge of freon, then we can get an evaporator.
Darren

geolab

Brian, I think you got the answer.

YES, a few times when I turn the temp **** ONE click from blue, hot air comes out.
When I turn a few clicks more, I can hear the flap servos functioning, and mild air comes out.
could it be the temp **** going crazy?

Yes I clear the code each time and it comes back after 2 or 3 times of using the A/C. I have a PST2 at home.
If I use the A/C on blue dot only, no error codes of course